Статті в журналах: "Strongly interacting quantum systems"

1

Ripka, Fabian, Harald Kübler, Robert Löw, and Tilman Pfau. "A room-temperature single-photon source based on strongly interacting Rydberg atoms." Science 362, no. 6413 (October 25, 2018): 446–49. http://dx.doi.org/10.1126/science.aau1949.

Повний текст джерела

Анотація:

Tailored quantum states of light can be created via a transfer of collective quantum states of matter to light modes. Such collective quantum states emerge in interacting many-body systems if thermal fluctuations are overcome by sufficient interaction strengths. Therefore, ultracold temperatures or strong confinement are typically required. We show that the exaggerated interactions between Rydberg atoms allow for collective quantum states even above room temperature. The emerging Rydberg interactions lead both to suppression of multiple Rydberg state excitations and destructive interference due to polariton dephasing. We experimentally implemented a four-wave mixing scheme to demonstrate an on-demand single-photon source. The combination of glass cell technology, identical atoms, and operation around room temperature promises scalability and integrability. This approach has the potential for various applications in quantum information processing and communication.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Zaleski, T. A., and T. K. Kopeć. "Unconventional quantum critical points in systems of strongly interacting bosons." Physica B: Condensed Matter 449 (September 2014): 204–8. http://dx.doi.org/10.1016/j.physb.2014.05.038.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

3

See, Tian Feng. "Few-photon transport in strongly interacting light-matter systems: A scattering approach." International Journal of Quantum Information 17, no. 06 (September 2019): 1950050. http://dx.doi.org/10.1142/s0219749919500503.

Повний текст джерела

Анотація:

Engineering strong photon–photon interactions at the quantum level have been crucial in various areas of research, notably in quantum information processing and quantum simulation. It is often done by coupling matter strongly to light. A promising way to achieve this is via waveguide quantum electrodynamics (QED). Motivated by these advancements, we study few-photon transport in waveguide QED setups. First, we present a diagrammatic technique to systematically study multiphoton scattering based on the scattering formalism and Green’s function approach. We demonstrate our proposal through physically relevant examples involving scattering of few-photon states from two-level emitters as well as from arrays of correlated Kerr nonlinear resonators described by the Bose–Hubbard model. In the second part, we apply the diagrammatic technique that was developed to perform a comprehensive study on a Bose–Hubbard lattice with a quasi-periodic potential. This model exhibits many-body localisation. We compute the two-photon transmission probability and show that it carries signatures of the underlying localisation transition with close agreement to the participation ratio of the eigenstates. The systematic scattering approach provided in this paper provides a foundation for future works at the interface between quantum optics and condensed matter.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Yan, Zhiguang, Yu-Ran Zhang, Ming Gong, Yulin Wu, Yarui Zheng, Shaowei Li, Can Wang, et al. "Strongly correlated quantum walks with a 12-qubit superconducting processor." Science 364, no. 6442 (May 2, 2019): 753–56. http://dx.doi.org/10.1126/science.aaw1611.

Повний текст джерела

Анотація:

Quantum walks are the quantum analogs of classical random walks, which allow for the simulation of large-scale quantum many-body systems and the realization of universal quantum computation without time-dependent control. We experimentally demonstrate quantum walks of one and two strongly correlated microwave photons in a one-dimensional array of 12 superconducting qubits with short-range interactions. First, in one-photon quantum walks, we observed the propagation of the density and correlation of the quasiparticle excitation of the superconducting qubit and quantum entanglement between qubit pairs. Second, when implementing two-photon quantum walks by exciting two superconducting qubits, we observed the fermionization of strongly interacting photons from the measured time-dependent long-range anticorrelations, representing the antibunching of photons with attractive interactions. The demonstration of quantum walks on a quantum processor, using superconducting qubits as artificial atoms and tomographic readout, paves the way to quantum simulation of many-body phenomena and universal quantum computation.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Minguzzi, A., and P. Vignolo. "Strongly interacting trapped one-dimensional quantum gases: Exact solution." AVS Quantum Science 4, no. 2 (June 2022): 027102. http://dx.doi.org/10.1116/5.0077423.

Повний текст джерела

Анотація:

Understanding the effect of correlations in interacting many-body systems is one of the main challenges in quantum mechanics. While the general problem can only be addressed by approximate methods and numerical simulations, in some limiting cases, it is amenable to exact solutions. This Review collects the predictions coming from a family of exact solutions which allows us to obtain the many-body wavefunction of strongly correlated quantum fluids confined by a tight waveguide and subjected to any form of longitudinal confinement. It directly describes the experiments with trapped ultracold atoms where the strongly correlated regime in one dimension has been achieved. The exact solution applies to bosons, fermions, and mixtures. It allows us to obtain experimental observables such as the density profiles and momentum distribution at all momentum scales, beyond the Luttinger liquid approach. It also predicts the exact quantum dynamics at all the times, including the small oscillation regime yielding the collective modes of the system and the large quench regime where the system parameters are changed considerably. The solution can be extended to describe finite-temperature conditions, spin, and magnetization effects. The Review illustrates the idea of the solution, presents the key theoretical achievements, and the main experiments on strongly correlated one-dimensional quantum gases.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

de los Santos-Sánchez, Octavio, and Ricardo Román-Ancheyta. "Strain-spectroscopy of strongly interacting defects in superconducting qubits." Superconductor Science and Technology 35, no. 3 (January 31, 2022): 035005. http://dx.doi.org/10.1088/1361-6668/ac4150.

Повний текст джерела

Анотація:

Abstract The proper functioning of some micro-fabricated novel quantum devices, such as superconducting resonators and qubits, is severely affected by the presence of parasitic structural material defects known as tunneling two-level-systems (TLS). Recent experiments have reported unambiguous evidence of the strong interaction between individual (coherent) TLS using strain-assisted spectroscopy. This work provides an alternative and simple theoretical insight that illustrates how to obtain the spectral response of such strongly interacting defects residing inside the amorphous tunnel barrier of a qubit’s Josephson junction. Moreover, the corresponding spectral signatures obtained here may serve to quickly and efficiently elucidate the actual state of these interacting TLS in experiments based on strain or electric-field spectroscopy.

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Bohr, D., P. Schmitteckert, and P. Wölfle. "DMRG evaluation of the Kubo formula —Conductance of strongly interacting quantum systems." Europhysics Letters (EPL) 73, no. 2 (January 2006): 246–52. http://dx.doi.org/10.1209/epl/i2005-10377-6.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Janiš, V., and D. Vollhardt. "Coupling of quantum degrees of freedom in strongly interacting disordered electron systems." Physical Review B 46, no. 24 (December 15, 1992): 15712–15. http://dx.doi.org/10.1103/physrevb.46.15712.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Song, Xueyu, and Alexei A. Stuchebrukhov. "Outer‐sphere electron transfer in polar solvents: Quantum scaling of strongly interacting systems." Journal of Chemical Physics 99, no. 2 (July 15, 1993): 969–78. http://dx.doi.org/10.1063/1.465310.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Sachkou, Yauhen P., Christopher G. Baker, Glen I. Harris, Oliver R. Stockdale, Stefan Forstner, Matthew T. Reeves, Xin He, et al. "Coherent vortex dynamics in a strongly interacting superfluid on a silicon chip." Science 366, no. 6472 (December 19, 2019): 1480–85. http://dx.doi.org/10.1126/science.aaw9229.

Повний текст джерела

Анотація:

Quantized vortices are fundamental to the two-dimensional dynamics of superfluids, from quantum turbulence to phase transitions. However, surface effects have prevented direct observations of coherent two-dimensional vortex dynamics in strongly interacting systems. Here, we overcome this challenge by confining a thin film of superfluid helium at microscale on the atomically smooth surface of a silicon chip. An on-chip optical microcavity allows laser initiation of clusters of quasi–two-dimensional vortices and nondestructive observation of their decay in a single shot. Coherent dynamics dominate, with thermal vortex diffusion suppressed by five orders of magnitude. This establishes an on-chip platform with which to study emergent phenomena in strongly interacting superfluids and to develop quantum technologies such as precision inertial sensors.

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Qiu, Richard, Chieh-Wen Liu, Shuhao Liu, and Xuan Gao. "New Reentrant Insulating Phases in Strongly Interacting 2D Systems with Low Disorder." Applied Sciences 8, no. 10 (October 14, 2018): 1909. http://dx.doi.org/10.3390/app8101909.

Повний текст джерела

Анотація:

The metal-insulator transition (MIT) in two-dimension (2D) was discovered by Kravchenko et al. more than two decades ago in strongly interacting 2D electrons residing in a Si-metal-oxide-semiconductor field-effect transistor (Si-MOSFET). Its origin remains unresolved. Recently, low magnetic field reentrant insulating phases (RIPs), which dwell between the zero-field (B = 0) metallic state and the integer quantum Hall (QH) states where the Landau-level filling factor υ > 1, have been observed in strongly correlated 2D GaAs hole systems with a large interaction parameter, rs, (~20–40) and a high purity. A new complex phase diagram was proposed, which includes zero-field MIT, low magnetic field RIPs, integer QH states, fractional QH states, high field RIPs and insulating phases (HFIPs) with υ < 1 in which the insulating phases are explained by the formation of a Wigner crystal. Furthermore, evidence of new intermediate phases was reported. This review article serves the purpose of summarizing those recent experimental findings and theoretical endeavors to foster future research efforts.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

DIXON, J. M., and J. A. TUSZYŃSKI. "THE UNIVERSAL EQUATIONS OF MOTION FOR NONLINEAR FIELDS IN DIFFERENT BASES DESCRIBING STRONGLY INTERACTING MANY-BODY SYSTEMS WITH TWO-BODY INTERACTIONS." International Journal of Modern Physics B 09, no. 13n14 (June 30, 1995): 1611–37. http://dx.doi.org/10.1142/s0217979295000690.

Повний текст джерела

Анотація:

A brief account of the Method of Coherent Structures (MCS) is presented using a plane-wave basis to define a quantum field. It is also demonstrated that the form of the quantum field equations, obtained by MCS, although highly nonlinear for many-body systems with two-body interactions, is independent of the basis of states used for the definition of the field.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Martin, M. J., M. Bishof, M. D. Swallows, X. Zhang, C. Benko, J. von-Stecher, A. V. Gorshkov, A. M. Rey, and Jun Ye. "A Quantum Many-Body Spin System in an Optical Lattice Clock." Science 341, no. 6146 (August 8, 2013): 632–36. http://dx.doi.org/10.1126/science.1236929.

Повний текст джерела

Анотація:

Strongly interacting quantum many-body systems arise in many areas of physics, but their complexity generally precludes exact solutions to their dynamics. We explored a strongly interacting two-level system formed by the clock states in 87Sr as a laboratory for the study of quantum many-body effects. Our collective spin measurements reveal signatures of the development of many-body correlations during the dynamical evolution. We derived a many-body Hamiltonian that describes the experimental observation of atomic spin coherence decay, density-dependent frequency shifts, severely distorted lineshapes, and correlated spin noise. These investigations open the door to further explorations of quantum many-body effects and entanglement through use of highly coherent and precisely controlled optical lattice clocks.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

CLARK, JOHN W. "MEMORIAL TRIBUTE TO MANFRED L. RISTIG (1935–2011)." International Journal of Modern Physics B 27, no. 29 (November 5, 2013): 1347003. http://dx.doi.org/10.1142/s0217979213470036.

Повний текст джерела

Анотація:

Manfred Ristig was a leading contributor to the advancement of microscopic theory of strongly interacting quantum many-body systems for over four decades. This retrospective on his life and scientific career pays tribute to his pivotal role in the development of correlated wavefunction approaches to quantitative ab initio description of quantum fluids, nuclear systems and condensed matter more generally. Highlights include his contributions to the formulation of Fermi hypernetted chain theory and correlated density matrix theory. Special attention is given to Ristig's seminal work of recent years, which has yielded rich insights into the interplay of exchange effects (arising from quantum statistics) and the strong interactions between constituent bosons or fermions.

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Dixon, J. M., and J. A. Tuszynski. "Coherent structures in strongly interacting many-body systems. II. Classical solutions and quantum fluctuations." Journal of Physics A: Mathematical and General 22, no. 22 (November 21, 1989): 4895–920. http://dx.doi.org/10.1088/0305-4470/22/22/018.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

16

GALLAIS, YANN, THOMAS H. KIRSCHENMANN, JUN YAN, ARON PINCZUK, LOREN N. PFEIFFER, and KEN W. WEST. "The Spin Excitation Spectrum in Quantum Hall Systems: Insights from Light Scattering Experiments." International Journal of Modern Physics B 21, no. 08n09 (April 10, 2007): 1209–18. http://dx.doi.org/10.1142/s0217979207042653.

Повний текст джерела

Анотація:

Collective spin excitations in quantum Hall systems are studied via inelastic light scattering. In the fractional quantum Hall effect regime, composite fermion spin excitations are observed in the range 1/3< ν <2/5. They reveal a transition from free to strongly interacting composite fermions. At ν=1, a shift of the spin-wave energy at finite wavevector from the bare Zeeman energy is observed. It allows us to evaluate the spin-stiffness of the quantum Hall ferromagnet.

Стилі APA, Harvard, Vancouver, ISO та ін.

17

LIU, YU-LIANG. "UNIVERSAL DESCRIPTION OF STRONGLY CORRELATED SYSTEMS." International Journal of Modern Physics B 16, no. 05 (February 20, 2002): 773–802. http://dx.doi.org/10.1142/s0217979202009949.

Повний текст джерела

Анотація:

In the eigen-functional theoretical framework, exact/accurate treatment of high-dimensional strongly correlated electron systems may be realized. The two key steps of this method are that under the path integral formulation we first change a D-dimensional quantum many-particle system into an (D+1)-dimensional (time-dependent) effective "single-particle" problem, then by solving the eigen-equation of the propagator operator of the particles, we can obtain the ground state energy functional and action, respectively. Under the eigen-functional theory, the problems of quantum many-particle systems end in to solve the equation of phase fields that are completely determined by the electron interaction. In practice this equation of the phase fields can be numerically solved for large lattice sites. After replacing the real time by the imaginary time, this method can also be applied for finite temperature cases.

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Žnidarič, Marko, and Marko Ljubotina. "Interaction instability of localization in quasiperiodic systems." Proceedings of the National Academy of Sciences 115, no. 18 (April 16, 2018): 4595–600. http://dx.doi.org/10.1073/pnas.1800589115.

Повний текст джерела

Анотація:

Integrable models form pillars of theoretical physics because they allow for full analytical understanding. Despite being rare, many realistic systems can be described by models that are close to integrable. Therefore, an important question is how small perturbations influence the behavior of solvable models. This is particularly true for many-body interacting quantum systems where no general theorems about their stability are known. Here, we show that no such theorem can exist by providing an explicit example of a one-dimensional many-body system in a quasiperiodic potential whose transport properties discontinuously change from localization to diffusion upon switching on interaction. This demonstrates an inherent instability of a possible many-body localization in a quasiperiodic potential at small interactions. We also show how the transport properties can be strongly modified by engineering potential at only a few lattice sites.

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Cárdenas-Castillo, Luis Fernando, and Arturo Camacho-Guardian. "Strongly Interacting Bose Polarons in Two-Dimensional Atomic Gases and Quantum Fluids of Polaritons." Atoms 11, no. 1 (December 29, 2022): 3. http://dx.doi.org/10.3390/atoms11010003.

Повний текст джерела

Анотація:

Polarons are quasiparticles relevant across many fields in physics: from condensed matter to atomic physics. Here, we study the quasiparticle properties of two-dimensional strongly interacting Bose polarons in atomic Bose–Einstein condensates and polariton gases. Our studies are based on the non-self consistent T-matrix approximation adapted to these physical systems. For the atomic case, we study the spectral and quasiparticle properties of the polaron in the presence of a magnetic Feshbach resonance. We show the presence of two polaron branches: an attractive polaron, a low-lying state that appears as a well-defined quasiparticle for weak attractive interactions, and a repulsive polaron, a metastable state that becomes the dominant branch at weak repulsive interactions. In addition, we study a polaron arising from the dressing of a single itinerant electron by a quantum fluid of polaritons in a semiconductor microcavity. We demonstrate the persistence of the two polaron branches whose properties can be controlled over a wide range of parameters by tuning the cavity mode.

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Enss, Tilman, and Joseph H. Thywissen. "Universal Spin Transport and Quantum Bounds for Unitary Fermions." Annual Review of Condensed Matter Physics 10, no. 1 (March 10, 2019): 85–106. http://dx.doi.org/10.1146/annurev-conmatphys-031218-013732.

Повний текст джерела

Анотація:

We review recent advances in experimental and theoretical understanding of spin transport in strongly interacting Fermi gases. The central new phenomenon is the observation of a lower bound on the (bare) spin diffusivity in the strongly interacting regime. Transport bounds are of broad interest for the condensed matter community, with a conceptual similarity to observed bounds in shear viscosity and charge conductivity. We discuss the formalism of spin hydrodynamics, how dynamics are parameterized by transport coefficients, the effect of confinement, the role of scale invariance, the quasiparticle picture, and quantum critical transport. We conclude by highlighting open questions, such as precise theoretical bounds, relevance to other phases of matter, and extensions to lattice systems.

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Ageev, Dmitry. "Holography, quantum complexity and quantum chaos in different models." EPJ Web of Conferences 191 (2018): 06006. http://dx.doi.org/10.1051/epjconf/201819106006.

Повний текст джерела

Анотація:

This contribution to Quarks’2018 conference proceedings is based on the talk presenting papers [1, 2] at the conference. These papers are devoted to the holographic description of chaos and quantum complexity in the strongly interacting systems out of equilibrium. In the first part of the talk we present different holographic complexity proposals in out-of-equilibrium CFT following the local perturbation. The second part is devoted to the chaotic growth of the local operator at a finite chemical potential. There are numerous results stating that the chemical potential may lead to the chaos disappearance, and we confirm the results from holography.

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Bogoliubov, N. M., A. G. Izergin, N. A. Kitanine, A. G. Pronko, and J. Timonen. "Quantum Dynamics of Strongly Interacting Boson Systems: Atomic Beam Splitters and Coupled Bose-Einstein Condensates." Physical Review Letters 86, no. 20 (May 14, 2001): 4439–42. http://dx.doi.org/10.1103/physrevlett.86.4439.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Dolan, B. P. "Duality in strongly interacting systems: 𝒩 = 2 SUSY Yang-Mills and the quantum Hall effect". Fortschritte der Physik 59, № 11-12 (18 липня 2011): 1174–86. http://dx.doi.org/10.1002/prop.201100055.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Savasta, Salvatore, Omar Di Stefano, and Franco Nori. "Thomas–Reiche–Kuhn (TRK) sum rule for interacting photons." Nanophotonics 10, no. 1 (November 18, 2020): 465–76. http://dx.doi.org/10.1515/nanoph-2020-0433.

Повний текст джерела

Анотація:

AbstractThe Thomas–Reiche–Kuhn (TRK) sum rule is a fundamental consequence of the position–momentum commutation relation for an atomic electron, and it provides an important constraint on the transition matrix elements for an atom. Here, we propose a TRK sum rule for electromagnetic fields which is valid even in the presence of very strong light–matter interactions and/or optical nonlinearities. While the standard TRK sum rule involves dipole matrix moments calculated between atomic energy levels (in the absence of interaction with the field), the sum rule here proposed involves expectation values of field operators calculated between general eigenstates of the interacting light–matter system. This sum rule provides constraints and guidance for the analysis of strongly interacting light–matter systems and can be used to test the validity of approximate effective Hamiltonians often used in quantum optics.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Gutierrez, Emmanuel Mercado, Gustavo Alves de Oliveira, Kilvia Mayre Farias, Vanderlei Salvador Bagnato, and Patricia Christina Marques Castilho. "Miscibility Regimes in a 23Na–39K Quantum Mixture." Applied Sciences 11, no. 19 (September 29, 2021): 9099. http://dx.doi.org/10.3390/app11199099.

Повний текст джерела

Анотація:

The effects of miscibility in interacting two-component classical fluids are relevant in a broad range of daily applications. When considering quantum systems, two-component Bose–Einstein condensates provide a well-controlled platform where the miscible–immiscible phase transition can be completely characterized. In homogeneous systems, this phase transition is governed only by the competition between intra- and inter-species interactions. However, in more conventional experiments dealing with trapped gases, the pressure of the confinement increases the role of the kinetic energy and makes the system more miscible. In the most general case, the miscibility phase diagram of unbalanced mixtures of different atomic species is strongly modified by the atom number ratio and the different gravitational sags. Here, we numerically investigate the ground-state of a 23Na–39K quantum mixture for different interaction strengths and atom number ratios considering realistic experimental parameters. Defining the spatial overlap between the resulting atomic clouds, we construct the phase diagram of the miscibility transition which could be directly measured in real experiments.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

McTague, Jonathan, and Jonathan J. Foley. "Non-Hermitian cavity quantum electrodynamics–configuration interaction singles approach for polaritonic structure with ab initio molecular Hamiltonians." Journal of Chemical Physics 156, no. 15 (April 21, 2022): 154103. http://dx.doi.org/10.1063/5.0091953.

Повний текст джерела

Анотація:

We combine ab initio molecular electronic Hamiltonians with a cavity quantum electrodynamics model for dissipative photonic modes and apply mean-field theories to the ground- and excited-states of resulting polaritonic systems. In particular, we develop a non-Hermitian configuration interaction singles theory for mean-field ground- and excited-states of the molecular system strongly interacting with a photonic mode and apply these methods to elucidating the phenomenology of paradigmatic polaritonic systems. We leverage the Psi4Numpy framework to yield open-source and accessible reference implementations of these methods.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Isar, Aurelian. "Coherence Dynamics of Two Interacting Bosonic Modes in a Thermal Environment." EPJ Web of Conferences 226 (2020): 01006. http://dx.doi.org/10.1051/epjconf/202022601006.

Повний текст джерела

Анотація:

We describe the time evolution of the quantum coherence in an open system consisting of two coupled bosonic modes embedded in a thermal reservoir. We discuss the influence of the environment in terms of the covariance matrix for initial squeezed thermal states. The coherence is quantified using the relative entropy as a measure, and its dynamics is studied in the framework of the theory of open systems based on completely positive quantum dynamical semigroups. We show that the evolution of the quantum coherence strongly depends on the initial state of the system (squeezing parameter and thermal photon numbers), the parameters characterizing the thermal reservoir (temperature and dissipation coefficient) and the intensity of the coupling between the two modes.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

FEINBERG, D., S. CIUCHI, and F. de PASQUALE. "SQUEEZING PHENOMENA IN INTERACTING ELECTRON-PHONON SYSTEMS." International Journal of Modern Physics B 04, no. 07n08 (June 1990): 1317–67. http://dx.doi.org/10.1142/s0217979290000656.

Повний текст джерела

Анотація:

The molecular crystal model of electrons coupled to Einstein phonons is studied as a function of the two parameters: the coupling constant A and the ratio of the electron-phonon coupling energy to the phonon energy, denoted by α. Both the one-electron and the many-electron models are studied, starting (for the former) from the adiabatic limit and (for the latter) from the anti-adiabatic one. In the “multiphonon” regime α>1, the sharp crossover between quasi-free electrons (λ≪1) and small polarons (λ≫1) is investigated, emphasizing the anomalous lattice fluctuations which occur in the intermediate regime (λ≈1). These fluctuations are due to the band motion of the electrons strongly coupled to the lattice and are shown in turn to weaken the electron mass renormalization inherent to self-trapping. In a relevant part of the intermediate region the effective electron mass slowly increases with λ, due to a competition between the phonon dressing effect and the reduction of lattice momentum fluctuations. This reduction is reminiscent of squeezing phenomena occurring in quantum optics. In a gaussian approximation squeezed phonon states imply a dynamical phonon softening.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Morvan, A., T. I. Andersen, X. Mi, C. Neill, A. Petukhov, K. Kechedzhi, D. A. Abanin, et al. "Formation of robust bound states of interacting microwave photons." Nature 612, no. 7939 (December 7, 2022): 240–45. http://dx.doi.org/10.1038/s41586-022-05348-y.

Повний текст джерела

Анотація:

AbstractSystems of correlated particles appear in many fields of modern science and represent some of the most intractable computational problems in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles1. The lack of general solutions for the three-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multiparticle bound states2–9. Here we develop a high-fidelity parameterizable fSim gate and implement the periodic quantum circuit of the spin-½ XXZ model in a ring of 24 superconducting qubits. We study the propagation of these excitations and observe their bound nature for up to five photons. We devise a phase-sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the idea that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

CLARK, J. W., V. A. KHODEL, and M. V. ZVEREV. "TOPOLOGICAL PHASE TRANSITIONS IN STRONGLY CORRELATED FERMI SYSTEMS." International Journal of Modern Physics B 23, no. 20n21 (August 20, 2009): 4059–73. http://dx.doi.org/10.1142/s0217979209063250.

Повний текст джерела

Анотація:

Opportunities for topological phase transitions in strongly correlated Fermi systems near a quantum critical point are explored as an alternative to collective scenarios for experimentally observed departures from standard Fermi-liquid behavior. Attention is focused on a quantum critical point at which the effective mass is divergent due to vanishing of the quasiparticle group velocity at the Fermi surface. Working within the original Landau quasiparticle theory, it is demonstrated that the quasiparticle picture can remain meaningful beyond the quantum critical point through rearrangements of the unstable normal Fermi surface and quasiparticle spectrum. Two possibilities emerge at zero temperature, depending on whether the quasiparticle interaction is regular or singular at zero momentum transfer. In the regular case, one type of topological phase transformation leads to a state with a multiconnected Fermi surface. In the singular case, another type of topological phase transition leads to an exceptional state containing a fermion condensate – the Fermi surface swells into a volume in momentum space, within which partial occupation prevails and quasiparticle energies are pinned to the chemical potential. As the temperature increases from zero to a characteristic value Tm, a crossover can occur from the state with multiple Fermi surfaces to that containing a fermion condensate.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Kleinert, Hagen. "Fractional quantum field theory, path integral, and stochastic differential equation for strongly interacting many-particle systems." EPL (Europhysics Letters) 100, no. 1 (October 1, 2012): 10001. http://dx.doi.org/10.1209/0295-5075/100/10001.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Andrade, Bárbara, Zohreh Davoudi, Tobias Graß, Mohammad Hafezi, Guido Pagano, and Alireza Seif. "Engineering an effective three-spin Hamiltonian in trapped-ion systems for applications in quantum simulation." Quantum Science and Technology 7, no. 3 (April 8, 2022): 034001. http://dx.doi.org/10.1088/2058-9565/ac5f5b.

Повний текст джерела

Анотація:

Abstract Trapped-ion quantum simulators, in analog and digital modes, are considered a primary candidate to achieve quantum advantage in quantum simulation and quantum computation. The underlying controlled ion–laser interactions induce all-to-all two-spin interactions via the collective modes of motion through Cirac–Zoller or Mølmer–Sørensen schemes, leading to effective two-spin Hamiltonians, as well as two-qubit entangling gates. In this work, the Mølmer–Sørensen scheme is extended to induce three-spin interactions via tailored first- and second-order spin–motion couplings. The scheme enables engineering single-, two-, and three-spin interactions, and can be tuned via an enhanced protocol to simulate purely three-spin dynamics. Analytical results for the effective evolution are presented, along with detailed numerical simulations of the full dynamics to support the accuracy and feasibility of the proposed scheme for near-term applications. With a focus on quantum simulation, the advantage of a direct analog implementation of three-spin dynamics is demonstrated via the example of matter-gauge interactions in the U(1) lattice gauge theory within the quantum link model. The mapping of degrees of freedom and strategies for scaling the three-spin scheme to larger systems, are detailed, along with a discussion of the expected outcome of the simulation of the quantum link model given realistic fidelities in the upcoming experiments. The applications of the three-spin scheme go beyond the lattice gauge theory example studied here and include studies of static and dynamical phase diagrams of strongly interacting condensed-matter systems modeled by two- and three-spin Hamiltonians.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

HENNING, P. A., K. NAKAMURA, and Y. YAMANAKA. "THERMAL FIELD THEORY IN NON-EQUILIBRIUM STATES." International Journal of Modern Physics B 10, no. 13n14 (June 30, 1996): 1599–614. http://dx.doi.org/10.1142/s0217979296000696.

Повний текст джерела

Анотація:

Conventional transport theory is not really applicable to nonequilibrium systems which exhibit strong quantum effects. We present two different approaches to overcome this problem. Firstly we point out how transport equations may be derived that incorporate a nontrivial spectral function as a typical quantum effect, and test this approach in a toy model of a strongly interacting degenerate plasma. Secondly we explore a path to include nonequilibrium effects into quantum field theory through momentum mixing transformations in Fock space. Although the two approaches are completely orthogonal, they lead to the same coherent conclusion.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Hess, P. W., P. Becker, H. B. Kaplan, A. Kyprianidis, A. C. Lee, B. Neyenhuis, G. Pagano, et al. "Non-thermalization in trapped atomic ion spin chains." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2108 (October 30, 2017): 20170107. http://dx.doi.org/10.1098/rsta.2017.0107.

Повний текст джерела

Анотація:

Linear arrays of trapped and laser-cooled atomic ions are a versatile platform for studying strongly interacting many-body quantum systems. Effective spins are encoded in long-lived electronic levels of each ion and made to interact through laser-mediated optical dipole forces. The advantages of experiments with cold trapped ions, including high spatio-temporal resolution, decoupling from the external environment and control over the system Hamiltonian, are used to measure quantum effects not always accessible in natural condensed matter samples. In this review, we highlight recent work using trapped ions to explore a variety of non-ergodic phenomena in long-range interacting spin models, effects that are heralded by the memory of out-of-equilibrium initial conditions. We observe long-lived memory in static magnetizations for quenched many-body localization and prethermalization, while memory is preserved in the periodic oscillations of a driven discrete time crystal state. This article is part of the themed issue ‘Breakdown of ergodicity in quantum systems: from solids to synthetic matter’.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

POPOVICI, CARINA. "DYSON–SCHWINGER APPROACH TO STRONGLY COUPLED THEORIES." Modern Physics Letters A 28, no. 09 (March 21, 2013): 1330006. http://dx.doi.org/10.1142/s0217732313300061.

Повний текст джерела

Анотація:

Although non-perturbative functional methods are often associated with low energy Quantum Chromodynamics, contemporary studies indicate that they provide reliable tools to characterize a much wider spectrum of strongly interacting many-body systems. In this paper, we aim to provide a modest overview on a few notable applications of Dyson–Schwinger equations to QCD and condensed matter physics. After a short introduction, we lay out some formal considerations and proceed by addressing the confinement problem. We discuss in some detail the heavy quark limit of Coulomb gauge QCD, in particular the simple connection between the non-perturbative Green's functions of Yang–Mills theory and the confinement potential. Landau gauge results on the infrared Yang–Mills propagators are also briefly reviewed. We then focus on less common applications, in graphene and high-temperature superconductivity. We discuss recent developments, and present theoretical predictions that are supported by experimental findings.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

CLARK, JOHN W., VICTOR A. KHODEL, HAOCHEN LI, and MIKHAIL V. ZVEREV. "THE SURPRISING PHENOMENON OF LEVEL MERGING IN FINITE FERMI SYSTEMS." International Journal of Modern Physics B 22, no. 25n26 (October 20, 2008): 4452–63. http://dx.doi.org/10.1142/s0217979208050206.

Повний текст джерела

Анотація:

When applied to a finite Fermi system having a degenerate single-particle spectrum, the Landau-Migdal Fermi-liquid approach leaves room for the possibility that different single-particle energy levels merge with one another. It will be argued that the opportunity for this behavior exists over a wide range of strongly interacting quantum many-body systems. An inherent feature of the mergence phenomenon is the presence of nonintegral quasiparticle occupation numbers, which implies a radical modification of the standard quasiparticle picture. Consequences of this alteration are surveyed for nuclear, atomic, and solid-state systems.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

CLARK, J. W., V. A. KHODEL, and M. V. ZVEREV. "DISSECTING AND TESTING COLLECTIVE AND TOPOLOGICAL SCENARIOS FOR THE QUANTUM CRITICAL POINT." International Journal of Modern Physics B 24, no. 25n26 (October 20, 2010): 4901–14. http://dx.doi.org/10.1142/s0217979210057080.

Повний текст джерела

Анотація:

In a number of strongly-interacting Fermi systems, the existence of a quantum critical point (QCP) is signaled by a divergent density of states and effective mass at zero temperature. Competing scenarios and corresponding mechanisms for the QCP are contrasted and analyzed. The conventional scenario invokes critical fluctuations of a collective mode in the close vicinity of a second-order phase transition and attributes divergence of the effective mass to a coincident vanishing of the quasiparticle pole strength. It is argued that this collective scenario is disfavored by certain experimental observations as well as theoretical inconsistencies, including violation of conservation laws applicable in the strongly interacting medium. An alternative topological scenario for the QCP is developed self-consistently within the general framework of Landau quasiparticle theory. In this scenario, the topology of the Fermi surface is transfigured when the quasiparticle group velocity vanishes at the QCP, yet the quasiparticle picture remains meaningful and no symmetry is broken. The topological scenario is found to explain the non-Fermi-liquid behavior observed experimentally in Yb-based heavy-fermion systems close to the QCP. This study suggests that integration of the topological scenario with the theory of second-order, symmetry-breaking quantum phase transitions will furnish a proper foundation for theoretical understanding of the extended QCP region.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

HAFEZI, M. "SYNTHETIC GAUGE FIELDS WITH PHOTONS." International Journal of Modern Physics B 28, no. 02 (December 15, 2013): 1441002. http://dx.doi.org/10.1142/s0217979214410021.

Повний текст джерела

Анотація:

In this article, we review the recent progress in the implementation of synthetic gauge fields for photons and the investigation of new photonic phenomena, such as non-equilibrium quantum Hall physics. In the first part, we discuss the implementation of magnetic-like Hamiltonians in coupled resonator systems and provide a pedagogical connection between the transfer matrix approach and the couple mode theory to evaluate the system Hamiltonian. In the second part, we discuss the investigation of nonequilibrium fractional quantum Hall physics in photonic systems. In particular, we show that driven strongly interacting photons exhibit interesting many-body behaviors which can be probed using the conventional optical measurement techniques.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Biehs, Svend-Age, Achim Kittel, and Philippe Ben-Abdallah. "Fundamental limitations of the mode temperature concept in strongly coupled systems." Zeitschrift für Naturforschung A 75, no. 8 (September 25, 2020): 803–7. http://dx.doi.org/10.1515/zna-2020-0204.

Повний текст джерела

Анотація:

AbstractWe theoretically analyze heat exchange between two quantum systems in interaction with external thermostats. We show that in the strong coupling limit the widely used concept of mode temperatures loses its thermodynamic foundation and therefore cannot be employed to make a valid statement on cooling and heating in such systems; instead, the incorrectly applied concept may result in a severe misinterpretation of the underlying physics. We illustrate these general conclusions by discussing recent experimental results reported on the nanoscale heat transfer through quantum fluctuations between two nanomechanical membranes separated by a vacuum gap.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Chen, Songtao, Mouktik Raha, Christopher M. Phenicie, Salim Ourari, and Jeff D. Thompson. "Parallel single-shot measurement and coherent control of solid-state spins below the diffraction limit." Science 370, no. 6516 (October 29, 2020): 592–95. http://dx.doi.org/10.1126/science.abc7821.

Повний текст джерела

Анотація:

Solid-state spin defects are a promising platform for quantum science and technology. The realization of larger-scale quantum systems with solid-state defects will require high-fidelity control over multiple defects with nanoscale separations, with strong spin-spin interactions for multi-qubit logic operations and the creation of entangled states. We demonstrate an optical frequency-domain multiplexing technique, allowing high-fidelity initialization and single-shot spin measurement of six rare-earth (Er3+) ions, within the subwavelength volume of a single, silicon photonic crystal cavity. We also demonstrate subwavelength control over coherent spin rotations by using an optical AC Stark shift. Our approach may be scaled to large numbers of ions with arbitrarily small separation and is a step toward realizing strongly interacting atomic defect ensembles with applications to quantum information processing and fundamental studies of many-body dynamics.

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Yamada, S., M. Machida, T. Kano, T. Imamura, and T. Koyama. "On-site pairing interaction and quantum coherence in strongly correlated systems." Journal of Physics and Chemistry of Solids 69, no. 12 (December 2008): 3395–97. http://dx.doi.org/10.1016/j.jpcs.2008.06.097.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Hubeny, Veronika E., and Mukund Rangamani. "A Holographic View on Physics out of Equilibrium." Advances in High Energy Physics 2010 (2010): 1–84. http://dx.doi.org/10.1155/2010/297916.

Повний текст джерела

Анотація:

We review the recent developments in applying holographic methods to understand nonequilibrium physics in strongly coupled field theories. The emphasis will be on elucidating the relation between evolution of quantum field theories perturbed away from equilibrium and the dual picture of dynamics of classical fields in black hole backgrounds. In particular, we discuss the linear response regime, the hydrodynamic regime, and finally the nonlinear regime of interacting quantum systems. We also describe how the duality might be used to learn some salient aspects of black hole physics in terms of field theory observables.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Levinsen, Jesper, Pietro Massignan, Georg M. Bruun, and Meera M. Parish. "Strong-coupling ansatz for the one-dimensional Fermi gas in a harmonic potential." Science Advances 1, no. 6 (July 2015): e1500197. http://dx.doi.org/10.1126/sciadv.1500197.

Повний текст джерела

Анотація:

A major challenge in modern physics is to accurately describe strongly interacting quantum many-body systems. One-dimensional systems provide fundamental insights because they are often amenable to exact methods. However, no exact solution is known for the experimentally relevant case of external confinement. We propose a powerful ansatz for the one-dimensional Fermi gas in a harmonic potential near the limit of infinite short-range repulsion. For the case of a single impurity in a Fermi sea, we show that our ansatz is indistinguishable from numerically exact results in both the few- and many-body limits. We furthermore derive an effective Heisenberg spin-chain model corresponding to our ansatz, valid for any spin-mixture, within which we obtain the impurity eigenstates analytically. In particular, the classical Pascal’s triangle emerges in the expression for the ground-state wave function. As well as providing an important benchmark for strongly correlated physics, our results are relevant for emerging quantum technologies, where a precise knowledge of one-dimensional quantum states is paramount.

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Kiczynski, M., S. K. Gorman, H. Geng, M. B. Donnelly, Y. Chung, Y. He, J. G. Keizer, and M. Y. Simmons. "Engineering topological states in atom-based semiconductor quantum dots." Nature 606, no. 7915 (June 22, 2022): 694–99. http://dx.doi.org/10.1038/s41586-022-04706-0.

Повний текст джерела

Анотація:

AbstractThe realization of controllable fermionic quantum systems via quantum simulation is instrumental for exploring many of the most intriguing effects in condensed-matter physics1–3. Semiconductor quantum dots are particularly promising for quantum simulation as they can be engineered to achieve strong quantum correlations. However, although simulation of the Fermi–Hubbard model4 and Nagaoka ferromagnetism5 have been reported before, the simplest one-dimensional model of strongly correlated topological matter, the many-body Su–Schrieffer–Heeger (SSH) model6–11, has so far remained elusive—mostly owing to the challenge of precisely engineering long-range interactions between electrons to reproduce the chosen Hamiltonian. Here we show that for precision-placed atoms in silicon with strong Coulomb confinement, we can engineer a minimum of six all-epitaxial in-plane gates to tune the energy levels across a linear array of ten quantum dots to realize both the trivial and the topological phases of the many-body SSH model. The strong on-site energies (about 25 millielectronvolts) and the ability to engineer gates with subnanometre precision in a unique staggered design allow us to tune the ratio between intercell and intracell electron transport to observe clear signatures of a topological phase with two conductance peaks at quarter-filling, compared with the ten conductance peaks of the trivial phase. The demonstration of the SSH model in a fermionic system isomorphic to qubits showcases our highly controllable quantum system and its usefulness for future simulations of strongly interacting electrons.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Hu, Qing, Dafei Jin, Jun Xiao, Sang Hoon Nam, Xiaoze Liu, Yongmin Liu, Xiang Zhang, and Nicholas X. Fang. "Ultrafast fluorescent decay induced by metal-mediated dipole–dipole interaction in two-dimensional molecular aggregates." Proceedings of the National Academy of Sciences 114, no. 38 (September 5, 2017): 10017–22. http://dx.doi.org/10.1073/pnas.1703000114.

Повний текст джерела

Анотація:

Two-dimensional molecular aggregate (2DMA), a thin sheet of strongly interacting dipole molecules self-assembled at close distance on an ordered lattice, is a fascinating fluorescent material. It is distinctively different from the conventional (single or colloidal) dye molecules and quantum dots. In this paper, we verify that when a 2DMA is placed at a nanometric distance from a metallic substrate, the strong and coherent interaction between the dipoles inside the 2DMA dominates its fluorescent decay at a picosecond timescale. Our streak-camera lifetime measurement and interacting lattice–dipole calculation reveal that the metal-mediated dipole–dipole interaction shortens the fluorescent lifetime to about one-half and increases the energy dissipation rate by 10 times that expected from the noninteracting single-dipole picture. Our finding can enrich our understanding of nanoscale energy transfer in molecular excitonic systems and may designate a unique direction for developing fast and efficient optoelectronic devices.

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Byczuk, Krzysztof, Walter Hofstetter, and Dieter Vollhardt. "ANDERSON LOCALIZATION VS. MOTT–HUBBARD METAL–INSULATOR TRANSITION IN DISORDERED, INTERACTING LATTICE FERMION SYSTEMS." International Journal of Modern Physics B 24, no. 12n13 (May 20, 2010): 1727–55. http://dx.doi.org/10.1142/s0217979210064575.

Повний текст джерела

Анотація:

We review recent progress in our theoretical understanding of strongly correlated fermion systems in the presence of disorder. Results were obtained by the application of a powerful nonperturbative approach, the dynamical mean-field theory (DMFT), to interacting disordered lattice fermions. In particular, we demonstrate that DMFT combined with geometric averaging over disorder can capture Anderson localization and Mott insulating phases on the level of one-particle correlation functions. Results are presented for the ground state phase diagram of the Anderson–Hubbard model at half-filling, both in the paramagnetic phase and in the presence of antiferromagnetic order. We find a new antiferromagnetic metal which is stabilized by disorder. Possible realizations of these quantum phases with ultracold fermions in optical lattices are discussed.

Стилі APA, Harvard, Vancouver, ISO та ін.

47

HALLBERG, K., JULIAN RINCON, and S. RAMASESHA. "QUANTUM PROPERTIES IN TRANSPORT THROUGH NANOSCOPIC RINGS: CHARGE-SPIN SEPARATION AND INTERFERENCE EFFECTS." International Journal of Modern Physics B 24, no. 25n26 (October 20, 2010): 5068–78. http://dx.doi.org/10.1142/s0217979210057213.

Повний текст джерела

Анотація:

Many of the most intriguing quantum effects are observed or could be measured in transport experiments through nanoscopic systems such as quantum dots, wires and rings formed by large molecules or arrays of quantum dots. In particular, the separation of charge and spin degrees of freedom and interference effects have important consequences in the conductivity through these systems. Charge-spin separation was predicted theoretically in one-dimensional strongly interacting systems (Luttinger liquids) and, although observed indirectly in several materials formed by chains of correlated electrons, it still lacks direct observation. We present results on transport properties through Aharonov-Bohm rings (pierced by a magnetic flux) with one or more channels represented by paradigmatic strongly-correlated models. For a wide range of parameters we observe characteristic dips in the conductance as a function of magnetic flux which are a signature of spin and charge separation. Interference effects could also be controlled in certain molecules and interesting properties could be observed. We analyze transport properties of conjugated molecules, benzene in particular, and find that the conductance depends on the lead configuration. In molecules with translational symmetry, the conductance can be controlled by breaking or restoring this symmetry, e.g. by the application of a local external potential. These results open the possibility of observing these peculiar physical properties in anisotropic ladder systems and in real nanoscopic and molecular devices.

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Mihaescu, Tatiana, and Aurelian Isar. "Dynamics of Entropy Production Rate in Two Coupled Bosonic Modes Interacting with a Thermal Reservoir." Entropy 24, no. 5 (May 14, 2022): 696. http://dx.doi.org/10.3390/e24050696.

Повний текст джерела

Анотація:

The Markovian time evolution of the entropy production rate is studied as a measure of irreversibility generated in a bipartite quantum system consisting of two coupled bosonic modes immersed in a common thermal environment. The dynamics of the system is described in the framework of the formalism of the theory of open quantum systems based on completely positive quantum dynamical semigroups, for initial two-mode squeezed thermal states, squeezed vacuum states, thermal states and coherent states. We show that the rate of the entropy production of the initial state and nonequilibrium stationary state, and the time evolution of the rate of entropy production, strongly depend on the parameters of the initial Gaussian state (squeezing parameter and average thermal photon numbers), frequencies of modes, parameters characterising the thermal environment (temperature and dissipation coefficient), and the strength of coupling between the two modes. We also provide a comparison of the behaviour of entropy production rate and Rényi-2 mutual information present in the considered system.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Pilar, Philipp, Daniele De Bernardis, and Peter Rabl. "Thermodynamics of ultrastrongly coupled light-matter systems." Quantum 4 (September 28, 2020): 335. http://dx.doi.org/10.22331/q-2020-09-28-335.

Повний текст джерела

Анотація:

We study the thermodynamic properties of a system of two-level dipoles that are coupled ultrastrongly to a single cavity mode. By using exact numerical and approximate analytical methods, we evaluate the free energy of this system at arbitrary interaction strengths and discuss strong-coupling modifications of derivative quantities such as the specific heat or the electric susceptibility. From this analysis we identify the lowest-order cavity-induced corrections to those quantities in the collective ultrastrong coupling regime and show that for even stronger interactions the presence of a single cavity mode can strongly modify extensive thermodynamic quantities of a large ensemble of dipoles. In this non-perturbative coupling regime we also observe a significant shift of the ferroelectric phase transition temperature and a characteristic broadening and collapse of the black-body spectrum of the cavity mode. Apart from a purely fundamental interest, these general insights will be important for identifying potential applications of ultrastrong-coupling effects, for example, in the field of quantum chemistry or for realizing quantum thermal machines.

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Fogarty, Thomás, Miguel Ángel García-March, Lea F. Santos, and Nathan L. Harshman. "Probing the edge between integrability and quantum chaos in interacting few-atom systems." Quantum 5 (June 29, 2021): 486. http://dx.doi.org/10.22331/q-2021-06-29-486.

Повний текст джерела

Анотація:

Interacting quantum systems in the chaotic domain are at the core of various ongoing studies of many-body physics, ranging from the scrambling of quantum information to the onset of thermalization. We propose a minimum model for chaos that can be experimentally realized with cold atoms trapped in one-dimensional multi-well potentials. We explore the emergence of chaos as the number of particles is increased, starting with as few as two, and as the number of wells is increased, ranging from a double well to a multi-well Kronig-Penney-like system. In this way, we illuminate the narrow boundary between integrability and chaos in a highly tunable few-body system. We show that the competition between the particle interactions and the periodic structure of the confining potential reveals subtle indications of quantum chaos for 3 particles, while for 4 particles stronger signatures are seen. The analysis is performed for bosonic particles and could also be extended to distinguishable fermions.

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Strongly interacting quantum systems"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями