Articles de revues sur le sujet « Open quantum system, quantum thermodynamics, quantum sensing »

In the last decade, experimentalists have demonstrated their impressive ability to control mechanical modes within mesoscopic objects down to the quantum level: it is now possible to create mechanical Fock states, to entangle mechanical modes from distinct objects, and to store quantum information or transfer it from one quantum bit to another, among the many possibilities found in today's literature. Indeed, mechanics is quantum, very much like spins or electromagnetic degrees of freedom; and all of this is, in particular, referred to as a new engineering resource for quantum technologies. However, there is also much more beyond this utilitarian aspect: invoking the original discussions of Braginsky and Caves, where a quantum oscillator is thought of as a quantum detector for a classical field, namely, a gravitational wave, which is also a unique sensing capability for quantum fields. The subject of study is then the baths to which the mechanical mode is coupled to, let them be known or unknown in nature. This Perspective is about this new potentiality that addresses stochastic thermodynamics, potentially down to its quantum version, the search for a fundamental underlying (random) field postulated in recent theories that can be affiliated to the class of the wave-function collapse models, and more generally open questions of condensed matter like the actual nature of the elusive (and ubiquitous) two-level systems present within all mechanical objects. However, such research turns out to be much more demanding than the use of a few quantum mechanical modes: all the known baths have to be identified, experiments have to be conducted in-equilibrium, and the word “mechanics” needs to be justified by a real ability to move substantially the center-of-mass when a proper drive tone is applied to the system.

Work is an important quantity in thermodynamics. In a closed quanutm system, the two-point energy measurements can be applied to measure the work but cannot be utilized in an open quantum system. With the two-point energy measurements, it has been shown that the work fluctuation satisfies the Jarzynski equality. We propose a scheme to measure the work in an open quantum system through the technique of reservoir engineering. Based on this scheme, we show that the work fluctuation in open quantum system may violate the Jarzynski equality. We apply our scheme to a two-level atom coupled to an engineered reservoir and numerically justify the general results, especially demonstrating that the second law of thermodynamics can be violated.

In this paper I want to enrich, on the methodological and epistemological side, an earlier review of mine (in which there are more details on the physics of electrodynamic coherence), aiming to stimulate attention to some seemingly trivial or irrelevant aspects, but, in my opinion, very subtle and of crucial importance in the study of living dynamics in various disciplines (physics, biology, medicine, philosophy of science). The conceptual core is: to understand that a living system cannot be conceived, and therefore neither studied, as “an object”, “a body.” The (in essence) relational nature of the living being finds its foundations in dissipation, symmetry breakings and field theories capable to count for multiple levels of vacuum (such as Quantum Field Theory, QFT), and sees the living phase of condensed matter (on an aqueous basis) as a consequence of bosonic condensation of correlation quanta (the well-known Nambu-Goldstone bosons) over an extended and interrelated hierarchy of degrees of freedom to which a (super)coherent is associated state. In there the matter and energy components of the biological system are subjected to phase correlations to give rise to a holo-state, shared over the whole system, from which a self, endowed with continuity, emerges and thus also a biological identity rooted in a dissipative thermodynamic history. However, this “identity” is like the river of Heraclitus’ anecdote: it is a flow and not an object existing in itself, nor static; dynamics, change, are all that lasts, while water, is always different. So holds for an organism that is, in fact, an organizationally closed system, but (and precisely because) thermodynamically open. This condition implies that the study of any biological system is de facto the study of a flow of relationships, and the living system (whether a cell, a complex organism, or an ecosystem) should be conceived as a process dissipatively coupled to its environment and as a producer of responses following an autopoietic order, inherent in the very condition of coherence (as long as it exists). Once this is recognized: • We obtain the possibility of reducing (without ontological discontinuities) sophisticated emergent properties (such as sensing, perception, semantics, teleology, adaptation, memory) irreducible to the deterministic laws of the elementary components of which, nonetheless, the living matter is composed (and to the laws of which it is therefore equally subjected); • Such properties result in the emergence of “biological laws” that, in addition to physical laws, dictating action-reaction relationships, describe stimulus-response relationships (with enormously greater logical openness) valid only for the living state; • The existence of these “laws” (analogical, but now physically grounded) forces us to revisit the definition of causality in biology, understanding that the method of inquiry must be revisited on both the theory and praxis fronts (details in the text); • It is understood that the complex view is to be applied ab initio, but also advanced to a further step (on a quantum-electrodynamic basis) in which the occurrence of not-only-diachronic causality in the living matter would be uncontemplable through “classical” observables only, considered within dynamical systems theory, chaos physics and complexity science. This gives rise to constructive methodological provocations, significant for research in biology, biophysics, and medicine, and for their application within humankind and its relationships to technology and Nature, in the name of a respectful and sensitive gesture towards the web of Life.

We develop a perturbation theory to estimate the finite time corrections around a quasi static trajectory, in which a quantum system is able to equilibrate at each instant with its environment. The results are then applied to non equilibrium thermodynamics, in which context we are able to provide a connection between the irreversible contributions and the microscopic details of the dynamical map generating the evolution. Turning the attention to finite time Carnot engines, we found a universal connection between the spectral density esponent of the hot/cold thermal baths and the efficiency at maximum power, giving also a new interpretation to already known results such as the Curzon-Ahborn and the Schmiedl-Seifert efficiencies.

The dynamical convergence of a system to the thermal distribution, or Gibbs state, is a standard assumption across all of the physical sciences. The Gibbs state is determined just by temperature and energies of the system. However, at decreasing system sizes, i.e., for nanoscale and quantum systems, the interaction with their environments is not negligible. The question then arises: Is the system's steady state still the Gibbs state? If not, how may the steady state depend on the interaction details? Here, we provide an overview of recent progress on answering these questions. We expand on the state of the art along two general avenues: First, we take the static point-of-view, which postulates the so-called mean force Gibbs state. This view is commonly adopted in the field of strong coupling thermodynamics, where modified laws of thermodynamics and nonequilibrium fluctuation relations are established on the basis of this modified state. Second, we take the dynamical point of view, originating from the field of open quantum systems, which examines the time-asymptotic steady state within two paradigms. We describe the mathematical paradigm, which proves return to equilibrium, i.e., convergence to the mean force Gibbs state, and then discuss a number of microscopic physical methods, particularly master equations. We conclude with a summary of established links between statics and equilibration dynamics and provide an extensive list of open problems. This comprehensive overview will be of interest to researchers in the wider fields of quantum thermodynamics, open quantum systems, mesoscopic physics, statistical physics, and quantum optics and will find applications whenever energy is exchanged on the nanoscale, from quantum chemistry and biology to magnetism and nanoscale heat management.

We establish a fluctuation theorem for an open quantum bipartite system that explicitly manifests the role played by quantum correlation. Generally quantum correlations may substantially modify the universality of classical thermodynamic relations in composite systems. Our fluctuation theorem finds a non-equilibrium parameter of genuinely quantum nature that sheds light on the emerging quantum information thermodynamics. Specifically we show that the statistics of quantum correlation fluctuation obtained in a time-reversed process can provide a useful insight into addressing work and heat in the resulting thermodynamic evolution. We illustrate these quantum thermodynamic relations by two examples of quantum correlated systems.

Operational quantum stochastic thermodynamics is a recently proposed theory to study the thermodynamics of open systems based on the rigorous notion of a quantum stochastic process or quantum causal model. In there, a stochastic trajectory is defined solely in terms of experimentally accessible measurement results, which serve as the basis to define the corresponding thermodynamic quantities. In contrast to this observer-dependent point of view, a `black box', which evolves unitarily and can simulate a quantum causal model, is constructed here. The quantum thermodynamics of this big isolated system can then be studied using widely accepted arguments from statistical mechanics. It is shown that the resulting definitions of internal energy, heat, work, and entropy have a natural extension to the trajectory level. The canonical choice of them coincides with the proclaimed definitions of operational quantum stochastic thermodynamics, thereby providing strong support in favour of that novel framework. However, a few remaining ambiguities in the definition of stochastic work and heat are also discovered and in light of these findings some other proposals are reconsidered. Finally, it is demonstrated that the first and second law hold for an even wider range of scenarios than previously thought, covering a large class of quantum causal models based solely on a single assumption about the initial system-bath state.

AbstractWe give a nonequilibrium Green’s function (NEGF) perspective on thermodynamics formulations for open quantum systems that are strongly coupled to baths. A scattering approach implying thermodynamic consideration of a supersystem (system plus baths) that is weakly coupled to external superbaths is compared with the consideration of thermodynamics of a system that is strongly coupled to its baths. We analyze both approaches from the NEGF perspective and argue that the latter yields a possibility of thermodynamic formulation consistent with a dynamical (quantum transport) description.

The dynamical description of a semi quantum nonlinear systems whose classical limit is not chaotic is still an open question. These systems are characterized by mixing a classical system with a quantum-mechanical one. As some of them lead to an irregular dynamics, the name "semi quantum chaos" arises. In this contribution we study two different Hamiltonians through the Maximum Entropy Principle Approach (MEP). Taking advantage of the MEP formalism, it can be clearly established that the Hamiltonians belonging to the SU(2) Lie algebra have common properties and a common treatment can be developed for them. These Hamiltonians resemble a quantum spin system coupled to a classical cavity. In the present contribution, we show that all of them share the generalized uncertainty principle as an invariant of the motion and other invariants as well. Two different classical potentials V(q) have been studied. Their specific heat are evaluated in terms of the extensive (mean values) and the intensive (Lagrange multipliers) variables. The main result of the present contribution is to show that the specific heat of these systems can be fixed independently of the temperature by setting only the initial conditions on the extensive or intensive variables, as well as the value of the quantum-classical coupling parameter. It could be possible to infer that this result can be extended to generalized forms for the V(q) classical potential.

Quantum correlations and associated quantum information concepts (e. g. quantum discord, entanglement, quantum Maxwell’s demon) provide novel insights in various quantum-information processing tasks, quantum-thermodynamics processes, open-system dynamics, quantum molecular dynamics, and general many-body physics. We investigate a new effect of correlations accompanying collision of two quantum systems A and B, the latter being part of a larger (interacting) system B+D. In contrast to the usual case of a classical ‘environment’ or ‘demon’ (which can have only classical correlations with A+B during and after the collision), the quantum case exhibits striking new features. Here, in the frame of incoherent inelastic neutron scattering (INS) and vibrational dynamics of molecules, we report experimental evidence of a new phenomenon: quantum deficit of momentum transfer in an elementary neutron-molecule collision, in particular, in INS from single H2O molecules confined in channels with sub-nanometer diameter. The INS findings are in clear contrast to conventional theoretical expectations, but are naturally (albeit qualitative) interpreted in the frame of modern theory of quantumness of correlations, thus also proposing a new operational meaning of quantum discord and related measures.

In this paper, we propose a Lyapunov-based state feedback control for state transfer based on the on-line quantum state estimation (OQSE). The OQSE is designed based on continuous weak measurements and compressed sensing. The controlled system is described by quantum master equation for open quantum systems, and the continuous measurement operators are derived according to the dynamic equation of system. The feedback control law is designed based on the Lyapunov stability theorem, and a strict proof of proposed control laws are given. At each sampling time, the state is estimated on-line, which is used to design the control law. The simulation experimental results show the effectiveness of the proposed feedback control strategy.

Abstract We study the ecological regime of quantum heat engines where the heat transfer between the environment and the engine is mediated with two qubits that act as energy filters and allow the conversion of heat into work. Using quantum thermodynamics, the theory of open quantum system and the fundamentals of finite-time thermodynamics we obtain the output power, the ecological function and the entropy production of the engine. Then, we optimize the functioning to the ecological function to find the range of efficiencies for which the system works optimally under the ecological criterium. We find that (i) the maximum value of the ecological function depends on the thermal copulings and the energies of the qubits that define the engine. (ii) We can define an ecological working region where the engine works producing a power that is similar to the maximum power but where it rejects much less heat to the environment. (iii) That the range of efficiencies defining the ecological region depends on the parameters defining the engine.(iv) An optimal working region where both the power and the ecological function are big is defined for each machine.

The role of proton tunnelling in biological catalysis is investigated here within the frameworks of quantum information theory and thermodynamics. We consider the quantum correlations generated through two hydrogen bonds between a substrate and a prototypical enzyme that first catalyses the tautomerization of the substrate to move on to a subsequent catalysis, and discuss how the enzyme can derive its catalytic potency from these correlations. In particular, we show that classical changes induced in the binding site of the enzyme spreads the quantum correlations among all of the four hydrogen-bonded atoms thanks to the directionality of hydrogen bonds. If the enzyme rapidly returns to its initial state after the binding stage, the substrate ends in a new transition state corresponding to a quantum superposition. Open quantum system dynamics can then naturally drive the reaction in the forward direction from the major tautomeric form to the minor tautomeric form without needing any additional catalytic activity. We find that in this scenario the enzyme lowers the activation energy so much that there is no energy barrier left in the tautomerization, even if the quantum correlations quickly decay.

Macroscopic many-body systems always exhibit irreversible behaviors. However, in principle, the underlying microscopic dynamics of the many-body system, either the (quantum) von Neumann or (classical) Liouville equation, guarantees that the entropy of an isolated system does not change with time, which is quite confusing compared with the macroscopic irreversibility. We notice that indeed the macroscopic entropy increase in standard thermodynamics is associated with the correlation production inside the full ensemble state of the whole system. In open systems, the irreversible entropy production of the open system can be proved to be equivalent with the correlation production between the open system and its environment. During the free diffusion of an isolated ideal gas, the correlation between the spatial and momentum distributions is increasing monotonically, and it could well reproduce the entropy increase result in standard thermodynamics. In the presence of particle collisions, the single-particle distribution always approaches the Maxwell-Boltzmann distribution as its steady state, and its entropy increase indeed indicates the correlation production between the particles. In all these examples, the total entropy of the whole isolated system keeps constant, while the correlation production reproduces the irreversible entropy increase in the standard macroscopic thermodynamics. In this sense, the macroscopic irreversibility and the microscopic reversibility no longer contradict with each other.

Remote sensing and manipulation of quantum emitters are functionalities of significant practical importance in quantum optics. Unfortunately, these abilities are considered as fundamentally challenging in systems of inhibited spontaneous emission. The reason is intimately related to the common perception that, in order to nullify the spontaneous emission decay rate, the system has to be electromagnetically closed, meaning that all loss channels should be avoided, including radiation. However, since radiation is prohibited in these systems, far-field sensing and by reciprocity, also far-field manipulation are considered impossible. Here, we suggest a possible solution to this challenge and theoretically propose an electromagnetically open system that may exhibit a complete inhibition of spontaneous emission while supporting guiding waves. This peculiar functionality is achieved through a feedback wave mechanism that is found in parity–time-symmetric structure. The analysis is based on an exact Green’s function derivation as well as full wave simulations involving a realistic design for the sake of future experimental validation.

We study the coarse-graining approach to derive a generator for the evolution of an open quantum system over a finite time interval. The approach does not require a secular approximation but nevertheless generally leads to a Lindblad–Gorini–Kossakowski–Sudarshan generator. By combining the formalism with full counting statistics, we can demonstrate a consistent thermodynamic framework, once the switching work required for the coupling and decoupling with the reservoir is included. Particularly, we can write the second law in standard form, with the only difference that heat currents must be defined with respect to the reservoir. We exemplify our findings with simple but pedagogical examples.

Thermodynamic uncertainty relations (TURs) represent one of the few broad-based and fundamental relations in our toolbox for tackling the thermodynamics of nonequilibrium systems. One form of TUR quantifies the minimal energetic cost of achieving a certain precision in determining a nonequilibrium current. In this initial stage of our research program, our goal is to provide the quantum theoretical basis of TURs using microphysics models of linear open quantum systems where it is possible to obtain exact solutions. In paper [Dong et al., Entropy 2022, 24, 870], we show how TURs are rooted in the quantum uncertainty principles and the fluctuation–dissipation inequalities (FDI) under fully nonequilibrium conditions. In this paper, we shift our attention from the quantum basis to the thermal manifests. Using a microscopic model for the bath’s spectral density in quantum Brownian motion studies, we formulate a “thermal” FDI in the quantum nonequilibrium dynamics which is valid at high temperatures. This brings the quantum TURs we derive here to the classical domain and can thus be compared with some popular forms of TURs. In the thermal-energy-dominated regimes, our FDIs provide better estimates on the uncertainty of thermodynamic quantities. Our treatment includes full back-action from the environment onto the system. As a concrete example of the generalized current, we examine the energy flux or power entering the Brownian particle and find an exact expression of the corresponding current–current correlations. In so doing, we show that the statistical properties of the bath and the causality of the system+bath interaction both enter into the TURs obeyed by the thermodynamic quantities.

The idea of a canonical ensemble from Gibbs has been extended by Jean-Marie Souriau for a symplectic manifold where a Lie group has a Hamiltonian action. A novel symplectic thermodynamics and information geometry known as “Lie group thermodynamics” then explains foliation structures of thermodynamics. We then infer a geometric structure for heat equation from this archetypal model, and we have discovered a pure geometric structure of entropy, which characterizes entropy in coadjoint representation as an invariant Casimir function. The coadjoint orbits form the level sets on the entropy. By using the KKS 2-form in the affine case via Souriau’s cocycle, the method also enables the Fisher metric from information geometry for Lie groups. The fact that transverse dynamics to these symplectic leaves is dissipative, whilst dynamics along these symplectic leaves characterize non-dissipative phenomenon, can be used to interpret this Lie group thermodynamics within the context of an open system out of thermodynamics equilibrium. In the following section, we will discuss the dissipative symplectic model of heat and information through the Poisson transverse structure to the symplectic leaf of coadjoint orbits, which is based on the metriplectic bracket, which guarantees conservation of energy and non-decrease of entropy. Baptiste Coquinot recently developed a new foundation theory for dissipative brackets by taking a broad perspective from non-equilibrium thermodynamics. He did this by first considering more natural variables for building the bracket used in metriplectic flow and then by presenting a methodical approach to the development of the theory. By deriving a generic dissipative bracket from fundamental thermodynamic first principles, Baptiste Coquinot demonstrates that brackets for the dissipative part are entirely natural, just as Poisson brackets for the non-dissipative part are canonical for Hamiltonian dynamics. We shall investigate how the theory of dissipative brackets introduced by Paul Dirac for limited Hamiltonian systems relates to transverse structure. We shall investigate an alternative method to the metriplectic method based on Michel Saint Germain’s PhD research on the transverse Poisson structure. We will examine an alternative method to the metriplectic method based on the transverse Poisson structure, which Michel Saint-Germain studied for his PhD and was motivated by the key works of Fokko du Cloux. In continuation of Saint-Germain’s works, Hervé Sabourin highlights the, for transverse Poisson structures, polynomial nature to nilpotent adjoint orbits and demonstrated that the Casimir functions of the transverse Poisson structure that result from restriction to the Lie–Poisson structure transverse slice are Casimir functions independent of the transverse Poisson structure. He also demonstrated that, on the transverse slice, two polynomial Poisson structures to the symplectic leaf appear that have Casimir functions. The dissipative equation introduced by Lindblad, from the Hamiltonian Liouville equation operating on the quantum density matrix, will be applied to illustrate these previous models. For the Lindblad operator, the dissipative component has been described as the relative entropy gradient and the maximum entropy principle by Öttinger. It has been observed then that the Lindblad equation is a linear approximation of the metriplectic equation

Direct geo-referencing system uses the technology of remote sensing to quickly grasp images, GPS tracks, and camera position. These data allows the construction of large volumes of images with geographic coordinates. So that users can be measured directly on the images. <br><br> In order to properly calculate positioning, all the sensor signals must be synchronized. Traditional aerial photography use Position and Orientation System (POS) to integrate image, coordinates and camera position. However, it is very expensive. And users could not use the result immediately because the position information does not embed into image. To considerations of economy and efficiency, this study aims to develop a direct geo-referencing system based on open source software and hardware platform. <br><br> After using Arduino microcontroller board to integrate the signals, we then can calculate positioning with open source software OpenCV. In the end, we use open source panorama browser, panini, and integrate all these to open source GIS software, Quantum GIS. A wholesome collection of data – a data processing system could be constructed.

Heat-Bath Algorithmic Cooling is a set of techniques for producing highly pure quantum systems by utilizing a surrounding heat-bath and unitary interactions. These techniques originally used the thermal environment only to fully thermalize ancillas at the environment temperature. Here we extend HBAC protocols by optimizing over the thermalization strategy. We find, for any d-dimensional system in an arbitrary initial state, provably optimal cooling protocols with surprisingly simple structure and exponential convergence to the ground state. Compared to the standard ones, these schemes can use fewer or no ancillas and exploit memory effects to enhance cooling. We verify that the optimal protocols are robusts to various deviations from the ideal scenario. For a single target qubit, the optimal protocol can be well approximated with a Jaynes-Cummings interaction between the system and a single thermal bosonic mode for a wide range of environmental temperatures. This admits an experimental implementation close to the setup of a micromaser, with a performance competitive with leading proposals in the literature. The proposed protocol provides an experimental setup that illustrates how non-Markovianity can be harnessed to improve cooling. On the technical side we 1. introduce a new class of states called maximallyactivestates and discuss their thermodynamic significance in terms of optimal unitary control, 2. introduce a new set of thermodynamic processes, called β-permutations, whose access is sufficient to simulate a generic thermalization process, 3. show how to use abstract toolbox developed within the resource theory approach to thermodynamics to perform challenging optimizations, while combining it with open quantum system dynamics tools to approximate optimal solutions within physically realistic setups.

This paper presents the results of an integration of Geographical Information Systems (GIS) and Remote Sensing (RS) techniques to delineate landslide susceptible areas in Lushoto district, Tanzania. To achieve this, the study has examined the distribution of landslide events and identified susceptible areas in the district. The study collected data through a handheld Global Positioning System (GPS), open-source databases and on-screen digitization. Analytical Hierarchy Process (AHP) technique was used to evaluate factors influencing landslides and Quantum GIS software was used to analyse landslides data through multi criteria technique to generate landslide susceptible areas. The study reveals that past landslides are more concentrated in the southern habitable areas of Lushoto district in which mudflow and rock falls are more dominant. The findings further expose that rainfall (29.97%) and slopes (21.72%), are the factors that have a higher influence on the occurrence of landslides while proximity to rivers (2.48%) and NDVI (1.69%) have very low influences. Further, the findings reveal that about 45% of the total area falls under moderate to very high landslides susceptible areas. This study concludes that a large area of Lushoto district’s southern part is at risk of being battered by landslides resulting from the influence of rainfall and slopes. As such the study recommends that governmental and non-governmental organizations should intervene through the formulation of policies against human activities that induce landslides in susceptible areas and to use these geospatial results to officially demarcate these areas to minimize fatalities and other economic and environmental impacts.

THE WORLD ACCORDING TO PHYSICS by Jim Al-Khalili. Princeton, NJ: Princeton University Press, 2020. 336 pages. Hardcover; $16.95. ISBN: 9780691182308. *The World According to Physics is Jim Al-Khalili's "ode to physics" (p. vii). While Al-Khalili has been publishing popular science for over twenty years, this is his first attempt to provide the layperson a cohesive overview of physics as a whole, linking together relativity, quantum mechanics, and thermodynamics into one unified (or rather, not yet unified) picture of the cosmos. "Ode" is appropriate, for the author's unrelenting adoration of his subject is apparent throughout; this is a child's dream fulfilled, and in many ways is a broader summa of the world according to the mature Al-Khalili, bringing together not only physics, but also his views on truth, society, and our future. *Khalili opens with a discussion of how the human mind craves narrative. Yet science has displaced much of the old myths and religions: "Contrary to what some people might argue, the scientific method is not just another way of looking at the world, nor is it just another cultural ideology or belief system. It is the way we learn about nature through trial and error, through experimentation and observation, through being prepared to replace ideas that turn out to be wrong or incomplete with better ones, and through seeing patterns in nature and beauty in the mathematical equations that describe these patterns. All the while we deepen our understanding and get closer to that "truth"--the way the world really is" (p. 2). *While physics is not just another "story," it does have a cosmic scale that gives it a captivating wonder of its own, providing the basis for chapter 2 ("Scale"). Physics encompasses the infinitely small (e.g., subatomic particles) as well as the infinitely large (e.g., the expansion of spacetime at the farthest reaches of existence). Further, its scope is not merely all of space but all of time as well, getting within decimal points of the first instant after the big bang, while providing prophetic approximations of how the cosmos might end. While Al-Khalili does not play his cards this early, his later chapters (pp. 242-43 in particular) will reveal that this extensive scope establishes physics as the most fundamental discipline, the reigning queen of the sciences. *The deeper project begins in chapter 3 ("Space and Time"). Al-Khalili wishes to display the underlying skeleton that comprise the unification project of physics, charting each merger until the final matchup is made (similar to a playoff line-up, where 16 teams soon become 8, then 4, then 2, then 1). Just as Newton wedded heaven and Earth through gravity, Einstein wedded space and time, explaining a diversity of phenomena with ever-simpler equations. While Al-Khalili's popular explanations of special and general relativity are merely adequate, his grasp of the broader narrative of unification in which these theories stand is incredibly useful, helping the layman see the trajectory of the book and physics as a whole, even when they cannot understand each individual step. *While chapter 3 unified space and time, chapter 4 ("Energy and Matter") unifies the energy and mass which warp said spacetime. Yet the unifications of relativity hit a snag when they come to "The Quantum World" (chapter 5) and to "Thermodynamics and the Arrow of Time" (chapter 6). While Einstein seems to rule over the kingdom of all things great, quantum mechanics rules over all things small, and no one has managed to negotiate a treaty just yet. Things do not work "down there" as they do "up here"; the laws of the macro are not the laws of the micro. Further, thermodynamics suggests that there is a directionality to time--for things move toward greater entropy--yet it is unclear how this can be made consistent with relativistic time or the conceptual reversibility of time in the quantum world. *Al-Khalili then moves in chapter 7 ("Unification") to possible reconciliations of these issues. He does an admirable job of explaining how the electromagnetic and weak nuclear forces were unified into the electroweak force, as well as explaining the ongoing attempt to unify the strong force with the electroweak force in a grand unified theory. This would leave only the holy grail: the attempt to unify gravity with the other three forces. String theory attempted such a unification by appealing to ten dimensions, yet by the 1990s there were five different string theories, which themselves needed to be unified, spawning M Theory (which required an additional eleventh dimension). An opposing contender soon arrived in loop quantum gravity. While string theory posits a quantum particle (the graviton) that exists within spacetime, loop quantum gravity inverts the order, making space more fundamental than a quantized particle within space, and so quantizing spacetime itself. These quanta of space are then "looped" together, determining the shape of spacetime. *Having unveiled the best approximations at a unified theory in physics today, Al-Khalili then ventures in chapter 8 to evaluate the subsequent state of the subject. He expresses frustration that no definitive proof has adjudicated between possible theories of everything, and that such unification seems further away now than it did thirty years ago. Even major discoveries, such as the Higgs boson, have mostly confirmed what we already suspected for decades, rather than genuinely pushing the envelope. Yet while he has given plenty of reason to be sceptical, Al-Khalili then lists recent developments that show that plausible models of quantum gravity continue to come forward, for example, Witten's M-Theory or Maldacena's gauge/gravity duality. Further, physics continues to make substantial technological contributions to daily life. This leads naturally into chapter 9 ("The Usefulness of Physics"). Particular attention is paid to the future possibilities of quantum computing for physics, medicine, AI, and a whole host of other multi-disciplinary simulations and processes that quantum superpositions would allow (for superpositions enable a greater degree of complexity in contrast to binary). *Al-Khalili concludes with a final chapter ("Thinking like a Physicist") about how physics and the scientific method can and should help govern public discourse. In this chapter, the true aim of his project comes to light, suggesting he is not providing a picture of the world according to physics, but the world as it simply is: "One day we may find a new theory of quantum gravity, but it will never predict that my ball will take twice or half as long as Newton's equation of motion predicts. That is an absolute truth about the world. There is no philosophical argument, no amount of meditation, no spiritual awakening or religious experience, or gut instinct or political ideology that could ever have told me that a ball dropped from a height of five metres would take one second to hit the ground. But science can tell me" (p. 276). *While Al-Khalili claimed in the preface that he would try to avoid metaphysical questions (p. xiii), he inevitably (and at times, self-consciously) stumbles back upon them, making ontological claims about the world-in-itself. Indeed, even his quest for unification is arguably based on a philosophical presupposition that unity is more fundamental than diversity, a tradition which came to fruition in Neoplatonism and Christian monotheism. While Al-Khalili acknowledges the need for philosophy and science to communicate (p. xiv), in practice he seems to treat philosophy as a useful tool for science when it hits a roadblock (e.g., for unpacking the implications of quantum mechanics) rather than a discipline in its own right that has the ability to question the underlying epistemic and ontological assumptions of science itself. As such, while his manner is more open and humble than your average humanist/materialist (he was elected president of the British Humanist Association in 2012), his actual beliefs do not seem to have absorbed much at all of the philosophical or theological complexity required for the sorts of claims he is making: "The human condition is bountiful beyond measure. We have invented art and poetry and music; we have created religions and political systems; we have built societies, cultures, and empires so rich and complex that no mere mathematical formula could ever encapsulate them. But, if we want to know where we come from, where the atoms in our bodies were formed--the "why" and "how" of the world and universe we inhabit--then physics is the path to a true understanding of reality. And with this understanding, we can shape our world and our destiny" (p. 281). *Ultimately, if one wants a helpful primer on physics, Al-Khalili provides a passionate and serviceable introduction. While his explanations of some topics were perhaps too much for newcomers, his weaving together of subjects often treated in isolation helps get things back on track, providing a grander narrative for lost readers to latch on to. Yet, if one is looking to see how this narrative fares as an all-encompassing account of the "why" and "how" of our world, then there are superior accounts available on the market. Indeed, thousands of years of writing and prayer have already sought out and encountered the One at the heart of creation. *Reviewed by Jonathan Lyonhart, University of Cambridge, Sidney Sussex College, Cambridge, UK CB2 3HU

THE WORLD ACCORDING TO PHYSICS by Jim Al-Khalili. Princeton, NJ: Princeton University Press, 2020. 336 pages. Hardcover; $16.95. ISBN: 9780691182308. *The World According to Physics is Jim Al-Khalili's "ode to physics" (p. vii). While Al-Khalili has been publishing popular science for over twenty years, this is his first attempt to provide the layperson a cohesive overview of physics as a whole, linking together relativity, quantum mechanics, and thermodynamics into one unified (or rather, not yet unified) picture of the cosmos. "Ode" is appropriate, for the author's unrelenting adoration of his subject is apparent throughout; this is a child's dream fulfilled, and in many ways is a broader summa of the world according to the mature Al-Khalili, bringing together not only physics, but also his views on truth, society, and our future. *Khalili opens with a discussion of how the human mind craves narrative. Yet science has displaced much of the old myths and religions: "Contrary to what some people might argue, the scientific method is not just another way of looking at the world, nor is it just another cultural ideology or belief system. It is the way we learn about nature through trial and error, through experimentation and observation, through being prepared to replace ideas that turn out to be wrong or incomplete with better ones, and through seeing patterns in nature and beauty in the mathematical equations that describe these patterns. All the while we deepen our understanding and get closer to that "truth"--the way the world really is" (p. 2). *While physics is not just another "story," it does have a cosmic scale that gives it a captivating wonder of its own, providing the basis for chapter 2 ("Scale"). Physics encompasses the infinitely small (e.g., subatomic particles) as well as the infinitely large (e.g., the expansion of spacetime at the farthest reaches of existence). Further, its scope is not merely all of space but all of time as well, getting within decimal points of the first instant after the big bang, while providing prophetic approximations of how the cosmos might end. While Al-Khalili does not play his cards this early, his later chapters (pp. 242-43 in particular) will reveal that this extensive scope establishes physics as the most fundamental discipline, the reigning queen of the sciences. *The deeper project begins in chapter 3 ("Space and Time"). Al-Khalili wishes to display the underlying skeleton that comprise the unification project of physics, charting each merger until the final matchup is made (similar to a playoff line-up, where 16 teams soon become 8, then 4, then 2, then 1). Just as Newton wedded heaven and Earth through gravity, Einstein wedded space and time, explaining a diversity of phenomena with ever-simpler equations. While Al-Khalili's popular explanations of special and general relativity are merely adequate, his grasp of the broader narrative of unification in which these theories stand is incredibly useful, helping the layman see the trajectory of the book and physics as a whole, even when they cannot understand each individual step. *While chapter 3 unified space and time, chapter 4 ("Energy and Matter") unifies the energy and mass which warp said spacetime. Yet the unifications of relativity hit a snag when they come to "The Quantum World" (chapter 5) and to "Thermodynamics and the Arrow of Time" (chapter 6). While Einstein seems to rule over the kingdom of all things great, quantum mechanics rules over all things small, and no one has managed to negotiate a treaty just yet. Things do not work "down there" as they do "up here"; the laws of the macro are not the laws of the micro. Further, thermodynamics suggests that there is a directionality to time--for things move toward greater entropy--yet it is unclear how this can be made consistent with relativistic time or the conceptual reversibility of time in the quantum world. *Al-Khalili then moves in chapter 7 ("Unification") to possible reconciliations of these issues. He does an admirable job of explaining how the electromagnetic and weak nuclear forces were unified into the electroweak force, as well as explaining the ongoing attempt to unify the strong force with the electroweak force in a grand unified theory. This would leave only the holy grail: the attempt to unify gravity with the other three forces. String theory attempted such a unification by appealing to ten dimensions, yet by the 1990s there were five different string theories, which themselves needed to be unified, spawning M Theory (which required an additional eleventh dimension). An opposing contender soon arrived in loop quantum gravity. While string theory posits a quantum particle (the graviton) that exists within spacetime, loop quantum gravity inverts the order, making space more fundamental than a quantized particle within space, and so quantizing spacetime itself. These quanta of space are then "looped" together, determining the shape of spacetime. *Having unveiled the best approximations at a unified theory in physics today, Al-Khalili then ventures in chapter 8 to evaluate the subsequent state of the subject. He expresses frustration that no definitive proof has adjudicated between possible theories of everything, and that such unification seems further away now than it did thirty years ago. Even major discoveries, such as the Higgs boson, have mostly confirmed what we already suspected for decades, rather than genuinely pushing the envelope. Yet while he has given plenty of reason to be sceptical, Al-Khalili then lists recent developments that show that plausible models of quantum gravity continue to come forward, for example, Witten's M-Theory or Maldacena's gauge/gravity duality. Further, physics continues to make substantial technological contributions to daily life. This leads naturally into chapter 9 ("The Usefulness of Physics"). Particular attention is paid to the future possibilities of quantum computing for physics, medicine, AI, and a whole host of other multi-disciplinary simulations and processes that quantum superpositions would allow (for superpositions enable a greater degree of complexity in contrast to binary). *Al-Khalili concludes with a final chapter ("Thinking like a Physicist") about how physics and the scientific method can and should help govern public discourse. In this chapter, the true aim of his project comes to light, suggesting he is not providing a picture of the world according to physics, but the world as it simply is: "One day we may find a new theory of quantum gravity, but it will never predict that my ball will take twice or half as long as Newton's equation of motion predicts. That is an absolute truth about the world. There is no philosophical argument, no amount of meditation, no spiritual awakening or religious experience, or gut instinct or political ideology that could ever have told me that a ball dropped from a height of five metres would take one second to hit the ground. But science can tell me" (p. 276). *While Al-Khalili claimed in the preface that he would try to avoid metaphysical questions (p. xiii), he inevitably (and at times, self-consciously) stumbles back upon them, making ontological claims about the world-in-itself. Indeed, even his quest for unification is arguably based on a philosophical presupposition that unity is more fundamental than diversity, a tradition which came to fruition in Neoplatonism and Christian monotheism. While Al-Khalili acknowledges the need for philosophy and science to communicate (p. xiv), in practice he seems to treat philosophy as a useful tool for science when it hits a roadblock (e.g., for unpacking the implications of quantum mechanics) rather than a discipline in its own right that has the ability to question the underlying epistemic and ontological assumptions of science itself. As such, while his manner is more open and humble than your average humanist/materialist (he was elected president of the British Humanist Association in 2012), his actual beliefs do not seem to have absorbed much at all of the philosophical or theological complexity required for the sorts of claims he is making: "The human condition is bountiful beyond measure. We have invented art and poetry and music; we have created religions and political systems; we have built societies, cultures, and empires so rich and complex that no mere mathematical formula could ever encapsulate them. But, if we want to know where we come from, where the atoms in our bodies were formed--the "why" and "how" of the world and universe we inhabit--then physics is the path to a true understanding of reality. And with this understanding, we can shape our world and our destiny" (p. 281). *Ultimately, if one wants a helpful primer on physics, Al-Khalili provides a passionate and serviceable introduction. While his explanations of some topics were perhaps too much for newcomers, his weaving together of subjects often treated in isolation helps get things back on track, providing a grander narrative for lost readers to latch on to. Yet, if one is looking to see how this narrative fares as an all-encompassing account of the "why" and "how" of our world, then there are superior accounts available on the market. Indeed, thousands of years of writing and prayer have already sought out and encountered the One at the heart of creation. *Reviewed by Jonathan Lyonhart, University of Cambridge, Sidney Sussex College, Cambridge, UK CB2 3HU

This study deals with the use of satellite TM multi-temporal data coupled with statistical analyses to quantitatively estimate urban expansion and soil consumption for small towns in southern Italy. The investigated area is close to Bari and was selected because highly representative for Italian urban areas. To cope with the fact that small changes have to be captured and extracted from TM multi-temporal data sets, we adopted the use of spectral indices to emphasize occurring changes, and geospatial data analysis to reveal spatial patterns. Analyses have been carried out using global and local spatial autocorrelation, applied to multi-date NASA Landsat images acquired in 1999 and 2009 and available free of charge. Moreover, in this paper each step of data processing has been carried out using free or open source software tools, such as, operating system (Linux Ubuntu), GIS software (GRASS GIS and Quantum GIS) and software for statistical analysis of data (R). This aspect is very important, since it puts no limits and allows everybody to carry out spatial analyses on remote sensing data. This approach can be very useful to assess and map land cover change and soil degradation, even for small urbanized areas, as in the case of Italy, where recently an increasing number of devastating flash floods have been recorded. These events have been mainly linked to urban expansion and soil consumption and have caused loss of human lives along with enormous damages to urban settlements, bridges, roads, agricultural activities, etc. In these cases, remote sensing can provide reliable operational low cost tools to assess, quantify and map risk areas.

<i>Ceropegia bulbosa</i> Roxb. is a narrow endemic, tuberous twiner of Asclepiadaceae family. It is medicinally important: tubers are nutritive and edible, leaves are digestive and a cure for dysentery and diarrhea. Exploitation for its tubers and poor regeneration of this species has shrunk its distribution. In order to know its present status, we report here the results of its appraisal in Rajasthan, using remote sensing and ground truthing in the past five years (2009&ndash;14). A base map of <i>C. bulbosa</i> was prepared using Geographical Information System (GIS), open source software Quantum GIS, SAGA. The Landsat Enhanced Thematic Mapper (ETM) +Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Global Digital Elevation Model (GDEM) Satellite Data were used in this study. ASTER and GDEM Data was clipped with district boundary and provided color range to get elevation information. A digital elevation model of Rajasthan physiography was developed from ASTER GDEM of 30-m resolution. GIS layers of Area of occurrences for <i>C. bulbosa</i> plant and elevation were created. This map along with topographic sheets of 1:50000 were used for field traversing and ground truthing as per GPS location inferred from map. Its geographic distribution was assessed using MaxEnt distribution modelling algorithm that employed 12 presence locality data, 19 bioclimatic variables, and elevation data. Results of this modelling predicted occurrence of <i>C. bulbosa</i> in the districts of Sirohi, Jalore, Barmer, Pali, Ajmer, Jhalawar, Dungarpur, Banswara, Baran, Kota, Bundi and Chittorgarh. Ground validation in these districts revealed its presence only at four places in three districts confirming its rarity. Analysis of dominance at their sites of occurrence revealed their poor populations and sub dominant status (RIV = 20&ndash;32) and very low density (2&ndash;12 plants per tenth ha).

Abstract In this article, we present a novel analysis of time-evolving networks, based on a thermodynamic representation of graph structure. We show how to characterize the evolution of time-varying complex networks by relating major structural changes to thermodynamic phase transitions. In particular, we derive expressions for a number of different thermodynamic quantities (specifically energy, entropy and temperature), which we use to describe the evolutionary behaviour of the network system over time. Since in the real world no system is truly closed and interactions with the environment are usually strong, we assume an open nature of the system. We adopt the Schrödinger picture as the dynamical representation of the quantum system over time. First, we compute the network entropy using a recent quantum mechanical representation of graph structure, connecting the graph Laplacian to a density operator. Then, we assume the system evolves according to the Schrödinger representation, but we allow for decoherence due to the interaction with the environment in a model akin to Environment-Induced Decoherence. We simplify the model by separating its dynamics into (a) an unknown time-dependent unitary evolution plus (b) an observation/interaction process, and this is the sole cause of the changes in the eigenvalues of the density matrix of the system. This allows us to obtain a measure of energy exchange with the environment through the estimation of the hidden time-varying Hamiltonian responsible for the unitary part of the evolution. Using the thermodynamic relationship between changes in energy, entropy, pressure and volume, we recover the thermodynamic temperature. We assess the utility of the method on real-world time-varying networks representing complex systems in the financial and biological domains. We also compare and contrast the different characterizations provided by the thermodynamic variables (energy, entropy, temperature and pressure). The study shows that the estimation of the time-varying energy operator strongly characterizes different states of a time-evolving system and successfully detects critical events occurring during network evolution.

We consider Markovian open quantum systems subject to stochastic resetting, which means that the dissipative time evolution is reset at randomly distributed times to the initial state. We show that the ensuing dynamics is non-Markovian and has the form of a generalized Lindblad equation. Interestingly, the statistics of quantum-jumps can be exactly derived. This is achieved by combining techniques from the thermodynamics of quantum-jump trajectories with the renewal structure of the resetting dynamics. We consider as an application of our analysis a driven two-level and an intermittent three-level system. Our findings show that stochastic resetting may be exploited as a tool to tailor the statistics of the quantum-jump trajectories and the dynamical phases of open quantum systems.

Abstract Quantum coherence, the ability of a quantum system to be in a superposition of orthogonal quantum states, is a distinct feature of the quantum mechanics, thus marking a deviation from classical physics. Coherence finds its applications in quantum sensing and metrology, quantum thermodynamics and computation. A particularly interesting is the possibility to observe coherence arising in counter-intuitive way from thermal energy that is without implementation of intricate protocols involving coherent driving sequences. In this manuscript, we investigate quantum coherence emerging in a hybrid system composed of a two-level system (qubit) and a thermal quantum harmonic oscillator (a material mechanical oscillator), inspired by recent experimental progress in fabrication of such systems. We show that quantum coherence is created in such a composite system solely from the interaction of the parts and persists under relevant damping. Implementation of such scheme will demonstrate previously unobserved mechanisms of coherence generation and can be beneficial for hybrid quantum technologies with mechanical oscillators and qubits.

Recently, the quantum formalism and methodology have been used in application to the modelling of information processing in biosystems, mainly to the process of decision making and psychological behaviour (but some applications in microbiology and genetics are considered as well). Since a living system is fundamentally open (an isolated biosystem is dead), the theory of open quantum systems is the most powerful tool for life-modelling. In this paper, we turn to the famous Schrödinger’s book “What is life?” and reformulate his speculations in terms of this theory. Schrödinger pointed to order preservation as one of the main distinguishing features of biosystems. Entropy is the basic quantitative measure of order. In physical systems, entropy has the tendency to increase (Second Law of Thermodynamics for isolated classical systems and dissipation in open classical and quantum systems). Schrödinger emphasized the ability of biosystems to beat this tendency. We demonstrate that systems processing information in the quantum-like way can preserve the order-structure expressed by the quantum (von Neumann or linear) entropy. We emphasize the role of the special class of quantum dynamics and initial states generating the camel-like graphs for entropy-evolution in the process of interaction with a new environment [Formula: see text]: 1) entropy (disorder) increasing in the process of adaptation to the specific features of [Formula: see text]; 2) entropy decreasing (order increasing) resulting from adaptation; 3) the restoration of order or even its increase for limiting steady state. In the latter case the steady state entropy can be even lower than the entropy of the initial state.

AbstractThe question of with what we associate work and heat in a quantum thermodynamic process has been extensively discussed, mostly for systems with time-dependent Hamiltonians. In this paper, we aim to investigate the energy exchanged between two quantum systems through interaction where the Hamiltonian of the system is time-independent. An entropy-based re-definitions of heat and work are presented for these quantum thermodynamic systems therefore an entropy-based formalism of both the first and the second laws of thermodynamics are introduced. We will use the genuine reasoning based on which Clausius originally defined work and heat. The change in the energy which is accompanied by a change in the entropy is identified as heat, while any change in the energy which does not lead to a change in the entropy is known as work. It will be seen that quantum coherence does not allow all the energy exchanged between two quantum systems to be only of the heat form. Several examples will also be discussed. Finally, we will examine irreversibility from our entropy-based formalism of quantum thermodynamics.

In this paper, we present a comprehensive account of quantum dissipation theories with the quadratic environment couplings. The theoretical development includes the Brownian solvation mode embedded hierarchical quantum master equations, a core-system hierarchy construction that verifies the extended dissipaton equation of motion (DEOM) formalism [R. X. Xu et al., J. Chem. Phys. 148, 114103 (2018)]. Developed are also the quadratic imaginary-time DEOM for equilibrium and the λ(t)-DEOM for nonequilibrium thermodynamics problems. Both the celebrated Jarzynski equality and Crooks relation are accurately reproduced, which in turn confirms the rigorousness of the extended DEOM theories. While the extended DEOM is more numerically efficient, the core-system hierarchy quantum master equation is favorable for "visualizing" the correlated solvation dynamics.

Abstract Recent studies have pointed out the intrinsic dependence of figures of merit of thermodynamic relevance – such as work, heat and entropy production – on the amount of quantum coherences that is made available to a system. However, whether coherences hinder or enhance the value taken by such quantifiers of thermodynamic performance is yet to be ascertained. We show that, when considering entropy production generated in a process taking a finite-size bipartite quantum system out of equilibrium through local non-unitary channels, no general monotonicity relationship exists between the entropy production and degree of quantum coherence in the state of the system. A direct correspondence between such quantities can be retrieved when considering specific forms of open-system dynamics applied to suitably chosen initial states. Our results call for a systematic study of the role of genuine quantum features in the non-equilibrium thermodynamics of quantum processes.

AbstractIdentifying the general mechanics behind the equilibration of a complex isolated quantum system towards a state described by only a few parameters has been the focus of attention in non-equilibrium thermodynamics. And several experimentally unproven conjectures are proposed for the statistical description of quantum (non-)integrable models. The plausible eigenstate thermalization hypothesis (ETH), which suggests that each energy eigenstate itself is thermal, plays a crucial role in understanding the quantum thermalization in non-integrable systems; it is commonly believed that it does not exist in integrable systems. Nevertheless, integrable systems can still relax to the generalized Gibbs ensemble. From a microscopic perspective, understanding the origin of this generalized thermalization that occurs in an isolated integrable system is a fundamental open question lacking experimental investigations. Herein, we experimentally investigated the spin subsystem relaxation in an isolated spin–orbit coupling quantum system. By applying the quantum state engineering technique, we initialized the system with various distribution widths in the mutual eigenbasis of the conserved quantities. Then, we compared the steady state of the spin subsystem reached in a long-time coherent dynamics to the prediction of a generalized version of ETH and the underlying mechanism of the generalized thermalization is experimentally verified for the first time. Our results facilitate understanding the origin of quantum statistical mechanics.

AbstractThe common reservoir can cause some unique effects, such as dark state and steady-state coherence, which are extensively studied in the dynamics of open quantum system. In this work, by means of collision model, we explore features of quantum thermodynamics induced by common reservoirs. We first construct general formulations of thermodynamic quantities for the system consisting of N coupling subsystems embedded in M common thermal reservoirs. We confirm the existence of nonlocal work due to simultaneous interactions of subsystems with the common reservoirs resembling what is found for nonlocal heat. With a system of two coupled qubits in a common reservoir, we show that steady-state currents could emerge even when interactions of individual subsystems and the reservoir fulfill strict energy conservation. We also exhibit the effect of dark state on the steady-state currents. We then examine relations between the work cost, the system’s nonequilibrium steady-state and the extractable work. In particular, we find that in the presence of dark state, the work cost is only related to the coherence generated in the dynamical evolution but not to the one contributed by the initial dark state of the system. We also show the possible transformation of coherence into useful work in terms of ergotropy. We finally examine the scale effect of reservoirs and show that the increase of the number of involved reservoirs need more work to be costed and meanwhile can produce more coherence so that more ergotropy can be extracted. The obtained features contribute to the understanding of thermodynamics in common reservoirs and would be useful in quantum technologies when common reservoirs are necessary.

AbstractExploring the source of free energy is of practical use for thermodynamical systems. In the classical regime, the free energy change is independent of magnetism, as the Lorentz force is conservative. In contrast, here we find that the free energy change can be amplified by adding a magnetic field to driven quantum systems. Taking a recent experimental system as an example, the predicted amplification becomes 3-fold when adding a 10-tesla magnetic field under temperature 316 nanoKelvin. We further uncover the mechanism by examining the driving process. Through extending the path integral approach for quantum thermodynamics, we obtain a generalized free energy equality for both closed and open quantum systems. The equality reveals a decomposition on the source of the free energy change: one is the quantum work functional, and the other emerges from the magnetic flux passing through a closed loop of propagators. The result suggests a distinct quantum effect of magnetic flux and supports to extract additional free energy from the magnetic field.

AbstractExploring the source of free energy is of practical use for thermodynamical systems. In the classical regime, the free energy change is independent of magnetism, as the Lorentz force is conservative. In contrast, here we find that the free energy change can be amplified by adding a magnetic field to driven quantum systems. Taking a recent experimental system as an example, the predicted amplification becomes 3-fold when adding a 10-tesla magnetic field under temperature 316 nanoKelvin. We further uncover the mechanism by examining the driving process. Through extending the path integral approach for quantum thermodynamics, we obtain a generalized free energy equality for both closed and open quantum systems. The equality reveals a decomposition on the source of the free energy change: one is the quantum work functional, and the other emerges from the magnetic flux passing through a closed loop of propagators. The result suggests a distinct quantum effect of magnetic flux and supports to extract additional free energy from the magnetic field.

AbstractImitating the transition from inanimate to living matter is a longstanding challenge. Artificial life has achieved computer programs that self-replicate, mutate, compete and evolve, but lacks self-organized hardwares akin to the self-assembly of the first living cells. Nonequilibrium thermodynamics has achieved lifelike self-organization in diverse physical systems, but has not yet met the open-ended evolution of living organisms. Here, I look for the emergence of an artificial-life code in a nonequilibrium physical system undergoing self-organization. I devise a toy model where the onset of self-replication of a quantum artificial organism (a chain of lambda systems) is owing to single-photon pulses added to a zero-temperature environment. I find that spontaneous mutations during self-replication are unavoidable in this model, due to rare but finite absorption of off-resonant photons. I also show that the replication probability is proportional to the absorbed work from the photon, thereby fulfilling a dissipative adaptation (a thermodynamic mechanism underlying lifelike self-organization). These results hint at self-replication as the scenario where dissipative adaptation (pointing towards convergence) coexists with open-ended evolution (pointing towards divergence).

Carbon quantum dots (CQDs) are environmentally friendly phosphors. However, there have been few reports on red-emitting CQDs with narrow-bandwidths, all of which were synthesized via solvothermal methods using autoclaves. Here,...

AbstractThe nature of the quantum-to-classical crossover remains one of the most challenging open question of Science to date. In this respect, moving objects play a specific role. Pioneering experiments over the last few years have begun exploring quantum behaviour of micron-sized mechanical systems, either by passively cooling single GHz modes, or by adapting laser cooling techniques developed in atomic physics to cool specific low-frequency modes far below the temperature of their surroundings. Here instead we describe a very different approach, passive cooling of a whole micromechanical system down to 500 μK, reducing the average number of quanta in the fundamental vibrational mode at 15 MHz to just 0.3 (with even lower values expected for higher harmonics); the challenge being to be still able to detect the motion without disturbing the system noticeably. With such an approach higher harmonics and the surrounding environment are also cooled, leading to potentially much longer mechanical coherence times, and enabling experiments questioning mechanical wave-function collapse, potentially from the gravitational background, and quantum thermodynamics. Beyond the average behaviour, here we also report on the fluctuations of the fundamental vibrational mode of the device in-equilibrium with the cryostat. These reveal a surprisingly complex interplay with the local environment and allow characteristics of two distinct thermodynamic baths to be probed.

In standard quantum mechanics, the Hamiltonian describing the physical system is generally Hermitian, so as to ensure that the system has real energy spectra and that the system's evolution is unitary. In recent years, it has been found that non-Hermitian Hamiltonians with parity-time (PT) symmetry also have real energy spectra, and there is a novel non-Hermitian exceptional point between PT-symmetric phase and PT-symmetry-broken phase, which is unique to Hermitian systems. Recently, people have realized PT symmetric and anti-PT symmetric non-Hermitian Hamiltonians in various physical systems and demonstrated novel quantum phenomena, which not only deepened our understanding of the basic laws of quantum physics, but also promoted the breakthrough of application technology. This review will introduce the basic physical principles of PT symmetry and anti-PT symmetry, summarize the schemes to realize PT symmetry and anti-PT symmetry in optical and atomic systems systematically, including the observation of PT-symmetry transitions by engineering time-periodic dissipation and coupling in ultracold atoms and single trapped ion, the realization of anti-PT symmetry in dissipative optical system by indirect coupling, and realizing anti-PT-symmetry through fast atomic coherent transmission in flying atoms. Finally, we review the research on precision sensing using non-Hermitian exceptional points of PT-symmetric systems. Near the exceptional points, the eigenfrequency splitting follows an <i>ε</i>^1/<i>N</i> -dependence, where the <i>ε</i> is the perturbation and <i>N</i> is the order of the exceptional point. We review the PT-symmetric system composed of three equidistant micro-ring cavities and enhanced sensitivity at third-order exceptional points. In addition, we also review the debate on whether exceptional-point sensors can improve the signal-to-noise ratio when considering noise and the current development of exceptional-point sensors, which is still an open and challenging question.

AbstractWe investigate the surface plasmon polariton dispersion and optical spectra of a thin film of tilted Weyl semimetal. Tilted Weyl semimetals possess tilted Weyl cones at the Weyl nodes and are categorized to type-I with closed Fermi surfaces and type-II with overtilted Weyl cones and open Fermi surfaces. We find that the surface plasmon polariton dispersion of this system is nonreciprocal even in the absence of the external magnetic field. Moreover, we demonstrate that the tilt parameter has a profound effect in controlling this nonreciprocity. We reveal that the thin film of type-II Weyl semimetal hosts the surface plasmon polariton modes with the negative group velocity. Furthermore, we show that the angular optical spectra of this structure are highly asymmetric and this angular asymmetry in the absorptivity and reflectivity depends profoundly on the tilt parameter of the tilted Weyl semimetal. These exciting features propose employing the tilted Weyl semimetals in optical sensing devices, optical data storage, and devices for quantum information processing.

We developed a colorimetric and fluorescence dual-signal sensor for detecting lipase activity based on methyl thioglycolate (MT) functionalized gold nanoparticles (MT-AuNPs) and CdS quantum dots (CdS QDs). It is the first time that was developed a dual-signal sensing strategy for lipase activity based on the inner-filter effect (IFE) between MT-AuNPs and CdS QDs. This probe system (MTAuNPs + CdS QDs) is sensitive and has selective response to the concentration of the lipase, and MT-AuNPs and CdS QDs played as transducer and fluorescer, respectively. The addition of lipase triggered the accumulation and change of color in CdS QDs and MT-AuNPs solution, it also makes CdS QDs’ fluorescence intensity significantly recover. The limit of detection (LOD) was as low as 0.039 μg mL-1 for colorimetric detection as well as 0.012 μg mL-1 for the fluorescence method. This method has been successfully used in the detection of commercial lipases. We believe it would open up a new path for the sensitive and high throughput lipase assay using nanobiosensor.

The dreams started to come true and journey started into reality when NASA succeed their mission to transport mankind on moon and reached on lunar surface on 20 July, 1969 at 20:17 UTC (Coordinated Universal Time) and after 6 hours and 39 minutes Armstrong became first person to step on lunar surface from Apollo Lunar Module Eagle on 21 July 1969 at 02:56 UTC. The amount of space time travel is affordable, bearable in this case with less advance technology only possible because of comparatively very near distance of Moon from planet Earth, but if mankind plan to establish journey from Earth to Mars or any other planet of our solar system or interstellar transportation including even today’s present very advanced Artificial intelligence based technologies of 2022 or ultra-advanced technologies in near future say 2030, 2040 human race might be successful or partially possible or possible with lots of obstacles, problems and risks. Several space analyst, scientists, astrophysicist, astronomers, quantum mechanics expert and researchers across world working on all these aspect with unique agenda how to minimise space time with increasing velocity of space shuttle to send mankind from planet Earth to other planets, stars and galaxies in deep Universe. Hence several scientists trying to match their space craft, space drive or space shuttle should be at least half to velocity of “Speed of Light” which is the ultimate speed of space transportation in known Universe, but unfortunately human civilization not succeeded in the same though several concepts proposed like “Warp drive, gravitational sling shots space shuttle, wormhole transport insertion from one surface and exit on another surface of bend or curvature space/ Universe using gravitational space drive and likewise. Hence globally conclude and accepted there is nothing more than of speed of light in known universe for fastest transportation and to explore and expand human civilization on another habitat planets, exoplanets and blanets come under habitable space zones and orbit having their energy stars or draft like Sun to have Earth-like environment. But as per my knowledge and experience “Everything is Vibrational Energy” with different frequencies. Even according to law of thermodynamics “Energy neither create nor destroyed, it’s only transform from one to another form” and it’s also relative by all universe sense according to Sir Albert Einstein whereas quantum mechanics also supports to all these phenomenon with the help of string theory, quantum entanglement and higher dimensions of space which also open to new door and direction to research for “Multiverse” and then after transport to it in far future. Therefore I am not challenging to any opinion but want put up my point of view regarding space transport and is “Speed of Consciousness and its generated output Thoughts has several times greater than speed of light and speed of light can’t be reached to speed of thoughts”. Why! Because everything is energy tuned on different frequencies, Multiverse, Universe, Black holes, warm holes, galaxies, stars, draft, moon’s, planets to earth, to earth life, to human and ultimately to “Human Brain”. Hence human Consciousness and all its generated thoughts are frequencies those has ultra-high speed as compare to speed of light only we need to discover how to extract, confine, beam and synchronised those thoughts with destination space planet and how to execute space travelling using it, but I must say it will be happen one day, We only need to think about it very seriously. According to me to send human aura on desired/destination planet or star or interstellar space human brain need to be retune to the vibrational frequency of destination space planet or location to generate equivalent frequency thoughts from retune brain consciousness which tuned on frequency of planet or deep universe to syncing brain, connect it and reach it there within fraction of second with creating “Space Tunnel of Consciousness” where millions, billions light years required to be reach. For example the most Earth-like exoplanet “Proxima Centauri B” and to reach even future technologies and Artificial Intelligence NASA proposed “Tree of Life project using Cubesats” minimum needs 200 years and 3 human generation old and die on planet Earth to be reach on Proxima Centauri B to contact if any human-like civilization there and to inform them life on earth with human entity and to know if any life on Proxima Centauri B with Human-like or any other intelligent civilization on it, because its orbit to red draft like sun of earth and situated in habitable zone out of our solar system hence called “Exoplanet” has high similarities index to Earth. The purpose to discuss using human brain consciousness and thoughts can be reach to Proxima Centauri B within a fraction of minute only need to discover how to match brain frequency with the quantum frequency of Proxima Centauri B to syncing, connect and transport Aura respective brain tune on Proxima Centauri B frequency to left body on Earth and reach Aura (Soul) on Proxima Centauri B with remain body on Earth on “Suspended Animation” or in general words deep sleep, long sleep or intentional coma. Just imagine before of 100 years I am telling you after 100 years you will have technology where using small electronic gadget you can communicate, control, navigate and explore complete world you might be not believe and laugh on it but today’s cell phones are live example of it. Similarly today what I am discussed with you, might be you not believe today but it will be reality of far future.

Creation is at a most basic level a somewhat lasting combination of parts arranged in new ways. On the one hand there is creation by competitive selection from random mutations. On the other is the deliberate work of authors masterminding creations. What these two processes tend to have in common is that the parts that go into the creative process are treated as rather neutral objects, much like clay to be shaped in meaningful ways. But what if the parts have a say in the process? Could the medium itself become a prime mover in acts of creation? If the parts that combine are not passive but can interact on their own, much like molecules in chemical reactions, then we fall into a new area between deliberate authoring, adaptive randomness. In this zone of interacting components and reflexive looping becomes a mechanism of creation. The Work of Hands Drawing Drawing Hands by the Dutch graphic artist M. C. Escher models the process of looping interaction. The lithograph shows a right hand that draws the cuffs of a left hand emerging out of the paper to draw cuffs on the right hand. In and out of the paper, the two hands draw each other into existence through this paradoxical loop. Escher's picture shows an implacable symmetry. The two hands are mirror images. They seem to belong to a single nonexistent person. Now imagine that Drawing Hands becomes an animation. The hands continue to draw each other in a circular process of creation. But there are two variations. The first animated version preserves the symmetry and yields an infinite regression of identical persons. In a second version, one of the hands overcomes the temptation of symmetry and draws a slightly different one. This second hand introduces further changes. The drawing process loops back to the first hand. Change continues to propagate through this open loop. If the hands cooperate, the creative possibilities of this mutual play could become endless. Think of these two versions of Escher's Drawing Hands as models of different types of reflexive creations. The first loop makes its own creator through a simple logic of self-interaction. If the process continues indefinitely, a repetition of self-made portraits would remain alone forever in the separate spaces of an endless regress of drawings within drawings of unbroken symmetries. The second animation shows a reflexive process of creation that relies on a loop of cooperative interactions without predetermined structural closure. It breaks with symmetry, or rather, does not rely on symmetry at all. Each hand is a separate autonomous agent, so to speak, entangled in a mutual process of construction. The introduction of reflexive differentiation yields a richly interacting universe in a shared space. Dialogues and Other Participations This second model reflects Luce Irigaray's insistence that nature cannot emerge from a singular entity. She notes that nature is at least two. It is male and female, for instance. There has to be a concert of differences between at least two partners to yield nature's richness. One creator is not enough, nor is one theory of everything. They cannot account for the diversity of life that is at the heart of nature. We need to begin with at least two distinct components. Irigaray notes that all speculation about overcoming the natural in the universal forgets that nature is not one (35). Just as importantly as having initial diversity is the presence of a mechanism that lets the diverse parts play. Nothing would come about in the absence of constructive interaction. There has to be a looping mechanism to link the different interactive partners. Physicist David Bohm applied this perspective to science. He saw nature forming itself through a dialogical process of mutual participation among radically different components. Furthermore, he observed that the process of dialogue is new to science itself. Bohm envisioned a participatory science. Science has been mainly based on the concept of arriving at one unique truth. But if scientists could engage in a dialogue, that would be a radical revolution in science—in the very nature of science (38). Mikhail Bakhtin introduced a sense of dialogue into the realm of art. He noted that discovery at the cognitive level is an act of creation closer to invention. For Bakhtin, art does not unveil or represent something that is already there. Art creates it in a dialogic concert between the artist and the medium. The medium includes the tools of the craft, subject matter, artistic communities, and a world filtered by artistic visions. Works of art result from a cooperative construction through dialogue between all these components. Creation happens through the dialogic confluence of different insights coming together in a loop of interactions. Bakhtin observed that the value of a work of art is not isolated and absolute. It lies in the work's potential or capacity to engage others in a creative dialogue. Language itself developed because of its interactive potential: it grew up in the service of participative thinking and performed acts (31). Bakhtin concluded that events, from the arts to the sciences, could only be described participatively. Without dialogue, isolated creative seeds would not blossom. Participants would not appreciate each other's insights. The circulation of dialogue and its engaging power is what facilitates the interaction of separate potentials that otherwise would not develop. In this sense, creation is participatory. It does not happen by itself. One hand creates another, and a different hand loops back to carry co-creation one turn further. In this dialogic process all is more or less subject to change, including how the evolving creation deals with its environment. Knowledge becomes pragmatic. Rather than an ensemble of absolutes, such as laws or truths, knowledge is more of a practical map to navigate an uncertain landscape. In this view, a truth, scientific or otherwise, is only as permanent as the interactive vortex that gives rise to it. This loop of co-creation goes beyond classical conceptions of truth and symmetry. What sets it apart is the cooperative use of differences in a circulation of mutual participation. In this model, feedback loops and differences work together as an engine of creation that runs on interactions. This engine of sorts spins loops that become self-maintaining vortices of innovation. From Closed to Open Loops Humberto Maturana and Francisco Varela pioneered the concept of autopoiesis in biology. An autopoietic system is basically a self-made and self-sustaining ensemble. To represent an autopoietic network, Maturana and Varela gave the example of the cell as a closed system of production. They noted in passing that the cell has to allow for some crossing of its own boundaries to exchange materials with the environment. Yet essentially, autopoietic mechanisms are closed with respect to its system of organization (135). The groundbreaking work of Maturana and Varela on self-organization gradually led to deeper reflections on how a system can maintain identity and yet be more open to exchanges with its environment, or, in other words, how an autopoietic system could operate as an open loop. The problem is that such reflections lead to a vast frontier mostly unexplored. There are no maps yet to begin making solid inroads into open systems. An inspiring exploration of open systems is Stuart Kauffman's Investigations. Although the term open seldom appears in his work as a category, its traces abound in this inquiry about creation in biological systems. Kauffman uses the concept of an autonomous agent where Maturana and Varela envisioned autopoietic systems (8). A free-living cell, for example, is no longer a closed, passive agent communicating through tightly guarded doors. Kauffman views the cell as actively interacting with its environment, yet at the same time able to maintain its self-identity until it dies. From the cellular to the universal, how is that possible? How can creative and destructive interactions yield life-enhancing innovation? Investigations is about biospheres taken in the general sense of living systems. The point of departure is the realization that biospheres cannot be prestated in their configuration space. This implies that we will always have uncertainty in any system, not just in quantum mechanics or in mathematics. As a consequence, we cannot state if any system is closed. Systems will always appear open, either because they are intrinsically open or because we cannot find their closure. Kauffman pictures autonomous agents propagating their systems of organization into all adjacent spaces where they can possibly migrate. Over their life spans, these agents maintain identity while propagating, by constantly repairing their systems as they go. They are also open to innovation because such repairs may entail adaptations to new environments. Both functions are the work of looping interactions within the environment, as living systems constantly check the adaptable viability of repairs and changes. The autonomous agent is like a hand feeling the environment, while the environment is another hand sensing the agent's actions. This forms an open co-constructive loop that is in effect an engine of innovation. We have yet to find the inner details of such engines. Kauffman thinks that innovative ecosystems may obey basic laws of nature yet to be discovered. But here his scientific approach may be touching a traditional home base rather than stretching further into the constructivist science he has imagined (269). Kauffman indicates that his investigations can only propose some partial and tentative ideas that cannot be proven at all in any formal sense. This in itself is an indication of an open scientific approach that departs from more traditional ones in the way basic ideas are generated. What is critical in Kauffman's approach is a sense of looping back to well-established areas that work and then jumping ahead to far reaching conjectures. This is the gesture of an explorer: moving further into the unknown, but also revisiting home to mark emerging trails through reinforcing loops that stretch out with each iteration. This process recalls Bohm's sense of dialogic or participatory science. Kauffman engages in a dialogue between traditional and innovative views without allowing one perspective to take over entirely. Kauffman concludes that the universe in its persistent becoming is richer than all our dreaming (139). For us the perceivers, as well as players and actors, our dreams are not isolated from our perceptions of the universe. They are not kept in different spaces but are engaged in a dialogical process of co-construction in the space of human imagination. Our co-created dreams and perceptions loop away from us to probe and map the unknown with an increasingly dialogical human touch. In scientific cultures, the notion of pre-existing laws of nature is being redrawn. As this gradual reconfiguration of scientific concepts develops, the quest for possible natural laws may be transformed, at least for the near term, into working principles that help us model phenomena. The fact that models work within their domains of application does not imply necessarily that their rules are actually laws of nature itself, or even that such laws might even exist. This subtle difference moves the scientific discourse from the metaphysical to a more human level where science is starting to feel increasingly at home. The same applies to artistic cultures, or to any other culture for that matter. Like hands drawing, we design architectures and adaptive rules to work in our environment. Different design principles can be viable, even if they are mutually contradictory in some way. Previous metaphysical concepts about unique designs of nature no longer have to hold back our hand, either in art or in science. Certainly they don't hold back innovation in media and technology. The basic work of trial and error helps creative hands co-design in ever-widening loops of reflexive interaction. This does not exclude other traditional creative procedures. Only now we have a richer palette of constructive alternatives. Acknowledgment I wish to thank Stuart Kauffman and Walter Fontana for inspiring conversations on innovation during my residency at the Santa Fe Institute in January 2002, and Quinnipiac University for supporting my research. References Arata, Luis O. "Reflections about Interactivity." 1999. Online. Internet. Available <http://media-in-transition.mit.edu/articles/index_arata.php>. Bakhtin, M. M. Toward a Philosophy of the Act. Austin: U of Texas P, 1993. Bohm, David. On Dialogue. New York: Routledge, 1996. Escher, M. C. Drawing Hands. http://www.etropolis.com/escher/hands.htm Irigaray, Luce. I Love to You. New York: Routledge, 1996. Kauffman, Stuart. Investigations. New York: Oxford, 2000. Maturana, Humberto and Francisco Varela. Autopoiesis and Cognition. Dordrecht: D. Reidel, 1980. Links http://media-in-transition.mit.edu/articles/index_arata.html http://www.etropolis.com/escher/hands.htm Citation reference for this article MLA Style Arata, Luis O.. "Creation by Looping Interactions" M/C: A Journal of Media and Culture 5.4 (2002). [your date of access] < http://www.media-culture.org.au/0208/creation.php>. Chicago Style Arata, Luis O., "Creation by Looping Interactions" M/C: A Journal of Media and Culture 5, no. 4 (2002), < http://www.media-culture.org.au/0208/creation.php> ([your date of access]). APA Style Arata, Luis O.. (2002) Creation by Looping Interactions. M/C: A Journal of Media and Culture 5(4). < http://www.media-culture.org.au/0208/creation.php> ([your date of access]).