Articles de revues : « Quantum-to-classical crossover »

1

Morr, Dirk K. « Crossover from quantum to classical transport ». Contemporary Physics 57, n^o 1 (6 octobre 2015) : 19–45. http://dx.doi.org/10.1080/00107514.2015.1075728.

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Ando, Tsuneya. « Quantum-to-classical crossover of quantum Hall effect ». Physica B : Condensed Matter 249-251 (juin 1998) : 84–88. http://dx.doi.org/10.1016/s0921-4526(98)00072-6.

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Agam, Oded, Igor Aleiner et Anatoly Larkin. « Shot Noise in Chaotic Systems : “Classical” to Quantum Crossover ». Physical Review Letters 85, n^o 15 (9 octobre 2000) : 3153–56. http://dx.doi.org/10.1103/physrevlett.85.3153.

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Schijven, P., J. Kohlberger, A. Blumen et O. Mülken. « Modeling the quantum to classical crossover in topologically disordered networks ». Journal of Physics A : Mathematical and Theoretical 45, n^o 21 (10 mai 2012) : 215003. http://dx.doi.org/10.1088/1751-8113/45/21/215003.

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Sereni, J. G. « Crossover from classical to quantum regime in Ce-lattice systems ». Physica B : Condensed Matter 398, n^o 2 (septembre 2007) : 412–15. http://dx.doi.org/10.1016/j.physb.2007.04.050.

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Slater, G. W. « Quantum-to-classical crossover in phonon emission from hot electrons ». Journal of Physics C : Solid State Physics 18, n^o 12 (30 avril 1985) : 2483–91. http://dx.doi.org/10.1088/0022-3719/18/12/011.

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Spiller, T. P., T. D. Clark, H. Prance, R. J. Prance et J. F. Ralph. « The quantum to classical crossover for a weak link capacitor ». Journal of Low Temperature Physics 101, n^o 5-6 (décembre 1995) : 1037–54. http://dx.doi.org/10.1007/bf00754523.

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Chen, L. Y., et S. C. Ying. « Theory of Surface Diffusion : Crossover from Classical to Quantum Regime ». Physical Review Letters 73, n^o 5 (1 août 1994) : 700–703. http://dx.doi.org/10.1103/physrevlett.73.700.

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9

van Wezel, Jasper, et Tjerk H. Oosterkamp. « A nanoscale experiment measuring gravity's role in breaking the unitarity of quantum dynamics ». Proceedings of the Royal Society A : Mathematical, Physical and Engineering Sciences 468, n^o 2137 (10 août 2011) : 35–56. http://dx.doi.org/10.1098/rspa.2011.0201.

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Modern, state-of-the-art nanomechanical devices are capable of creating spatial superpositions that are massive enough to begin to experimentally access the quantum to classical crossover, and thus force us to consider the possible ways in which the usual quantum dynamics may be affected. One recent theoretical proposal describes the crossover from unitary quantum mechanics to classical dynamics as a form of spontaneous symmetry breaking. Here, we propose a specific experimental set-up capable of identifying the source of unitarity breaking in such a mechanism. The experiment is aimed specifically at clarifying the role played by gravity, and distinguishes the resulting dynamics from that suggested by alternative scenarios for the quantum to classical crossover. We give both a theoretical description of the expected dynamics, and a discussion of the involved experimental parameter values and the proposed experimental protocol.

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Vojta, Thomas. « Quantum version of a spherical model : Crossover from quantum to classical critical behavior ». Physical Review B 53, n^o 2 (1 janvier 1996) : 710–14. http://dx.doi.org/10.1103/physrevb.53.710.

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11

Bambi, Hu, et Li Baowen. « Frenkel-Kontorova Model : Crossover from the Classical to the Quantum Mechanical ». Journal of the Korean Physical Society 34, n^o 92 (1 avril 1999) : 138. http://dx.doi.org/10.3938/jkps.34.138.

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Bihun, R. I., Z. V. Stasyuk et O. A. Balitskii. « Crossover from quantum to classical electron transport in ultrathin metal films ». Physica B : Condensed Matter 487 (avril 2016) : 73–77. http://dx.doi.org/10.1016/j.physb.2016.02.003.

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Caramico D'Auria, A., L. De Cesare et I. Rabuffo. « A nonconventional approach to describe classical-quantum crossover phenomena near criticality ». Physics Letters A 280, n^o 3 (février 2001) : 153–56. http://dx.doi.org/10.1016/s0375-9601(01)00039-1.

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Takov, I. P. « Classical to quantum crossover of the critical behaviour of impure systems ». Journal of Physical Studies 3, n^o 4 (1999) : 422–30. http://dx.doi.org/10.30970/jps.03.422.

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Parkinson, J. B., et J. C. Bonner. « Spin chains in a field : Crossover from quantum to classical behavior ». Physical Review B 32, n^o 7 (1 octobre 1985) : 4703–24. http://dx.doi.org/10.1103/physrevb.32.4703.

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Lai, Ying-Cheng, Edward Ott et Celso Grebogi. « Temporal crossover from classical to quantum behavior : a Markov-chain approach ». Physics Letters A 173, n^o 2 (février 1993) : 148–52. http://dx.doi.org/10.1016/0375-9601(93)90178-3.

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Vlasov, Sergei, Pavel F. Bessarab, Valery M. Uzdin et Hannes Jónsson. « Classical to quantum mechanical tunneling mechanism crossover in thermal transitions between magnetic states ». Faraday Discussions 195 (2016) : 93–109. http://dx.doi.org/10.1039/c6fd00136j.

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Transitions between states of a magnetic system can occur by jumps over an energy barrier or by quantum mechanical tunneling through the energy barrier. The rate of such transitions is an important consideration when the stability of magnetic states is assessed for example for nanoscale candidates for data storage devices. The shift in transition mechanism from jumps to tunneling as the temperature is lowered is analyzed and a general expression derived for the crossover temperature. The jump rate is evaluated using a harmonic approximation to transition state theory. First, the minimum energy path for the transition is found with the geodesic nudged elastic band method. The activation energy for the jumps is obtained from the maximum along the path, a saddle point on the energy surface, and the eigenvalues of the Hessian matrix at that point as well as at the initial state minimum used to estimate the entropic pre-exponential factor. The crossover temperature for quantum mechanical tunneling is evaluated from the second derivatives of the energy with respect to orientation of the spin vector at the saddle point. The resulting expression is applied to test problems where analytical results have previously been derived, namely uniaxial and biaxial spin systems with two-fold anisotropy. The effect of adding four-fold anisotropy on the crossover temperature is demonstrated. Calculations of the jump rate and crossover temperature for tunneling are also made for a molecular magnet containing an Mn₄ group. The results are in excellent agreement with previously reported experimental measurements on this system.

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18

Careri, Giorgio, Fabio Bruni et Giuseppe Consolini. « HOPPING AND DISSIPATIVE TUNNELING OF ORIENTATIONAL DEFECTS IN ICE ». International Journal of Modern Physics B 08, n^o 07 (30 mars 1994) : 839–46. http://dx.doi.org/10.1142/s0217979294000373.

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We have measured the dielectric relaxation time of orientational defects for H2O and D2O polycrystalline ice samples, in the temperature range 200–270 K, and over the frequency range 0.3–1000 kHz. Results are in good agreement with previous studies, and at T<240 K departures from the familiar Arrhenius law have been observed. We show that these deviations from classical rate theory can be well described within the framework of dissipative quantum tunneling (DQT) theory, assuming impurity-generated Bjerrum defects responsible for the observed dielectric relaxation process over the entire temperature range investigated. The temperature regions where quantum tunneling, crossover to thermal hopping, and quantum corrections to classical laws, respectively prevail are here reviewed. Particularly significant is the perfect agreement, near the crossover temperature Tc, of all our different samples with a universal scaling law, as predicted by DQT theory. The crossover temperature Tc, where quantum tunneling and thermal hopping merge, has been found close to 240 K and to 220 K for H2O and D2O ice respectively, thus showing the higher relevance of quantum effects in H2O ice. It is shown that the dielectric relaxation time of orientational defects for both H2O and D2O ice samples never attains a fully classical behaviour, even at their melting temperature.

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19

PARK, CHANG-SOO. « QUANTUM-CLASSICAL CROSSOVER OF THE ESCAPE RATE IN THE NANO-FERROMAGNET WITH COMPLEX CRYSTAL SYMMETRY ». Modern Physics Letters B 15, n^o 27 (20 novembre 2001) : 1237–47. http://dx.doi.org/10.1142/s0217984901003111.

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We investigate the quantum-classical crossover of the escape rate in the nanoscale ferromagnetic particle with complex crystal symmetries placed in an external field along the hard anisotropy axis. We use the periodic instanton technique based on the spin coherent state representation and the condition of the first-order crossover to determine the type of crossover. In the high field limit of ∊(=1-Hc/H)→0 the crossover is found to be second-order. We also calculate the crossover temperature with leading order behavior of T0~∊1/2.

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20

Zhou, Bin, Jiu-Qing Liang et Fu-Cho Pu. « Crossover from quantum tunneling to classical hopping of domain walls in ferromagnets ». Physica B : Condensed Matter 304, n^o 1-4 (septembre 2001) : 141–46. http://dx.doi.org/10.1016/s0921-4526(01)00318-0.

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Zaitsev-Zotov, S. V. « Classical-to-quantum crossover in charge-density wave creep at low temperatures ». Physical Review Letters 71, n^o 4 (26 juillet 1993) : 605–8. http://dx.doi.org/10.1103/physrevlett.71.605.

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Ota, Y., et I. Ohba. « The crossover from classical to quantum behavior in Duffing oscillator based on quantum state diffusion ». Pramana 59, n^o 2 (août 2002) : 409–12. http://dx.doi.org/10.1007/s12043-002-0134-0.

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GREEN, FREDERICK, et MUKUNDA P. DAS. « CLASSICAL TO QUANTUM CROSSOVER IN HIGH-CURRENT NOISE OF ONE-DIMENSIONAL BALLISTIC WIRES ». Fluctuation and Noise Letters 01, n^o 04 (décembre 2001) : C21—C33. http://dx.doi.org/10.1142/s0219477501000500.

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Microscopic current fluctuations and conductance are inseparable. We present a unified kinetic theory of both quantized conductance and nonequilibrium noise in one-dimensional ballistic wires. We show that high-current ballistic fluctuations depend, directly and robustly, on carrier statistics. This is dramatically evident in the large noise peaks predicted to coincide with the quantized steps in the two-probe conductance. The outstanding features of nonlinear ballistic fluctuations are: (i) their observability by standard experimental techniques; (ii) their strong suppression by electron degenercy; (iii) their divergence in any model that ignores the explicit dynamics of dissipative scattering in the macroscopic leads; (iv) their numerical dominance over the noise predictions of the Landauer-Büttiker model. The nonequilibrium noise of hot ballistic carriers is strikingly sensitive to their inelastic energy loss on entering the leads. Uniquely and quantitatively, it characterizes the observed nonideality of quantized conductance.

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Ota, Yukihiro, et Ichiro Ohba. « Crossover from classical to quantum behaviour of duffing oscillator through pseudo-Lyapunov exponent ». Journal of Modern Optics 51, n^o 6-7 (avril 2004) : 1099. http://dx.doi.org/10.1080/09500340408233639.

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Nie, Yi-Hang, Q. Liang et Q. W. Yan. « Crossover from quantum tunneling to classical hopping of barrier transition in nano-magnets ». Physics Letters A 299, n^o 5-6 (juillet 2002) : 586–92. http://dx.doi.org/10.1016/s0375-9601(02)00722-3.

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Lang, Gunther, Elisabetta Paladino et Ulrich Weiss. « Electron transfer in the nonadiabatic regime : Crossover from quantum-mechanical to classical behaviour ». Chemical Physics 244, n^o 1 (juin 1999) : 111–25. http://dx.doi.org/10.1016/s0301-0104(99)00115-9.

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Sheng, L., D. Y. Xing et Z. D. Wang. « Transport theory in metallic films : Crossover from the classical to the quantum regime ». Physical Review B 51, n^o 11 (15 mars 1995) : 7325–28. http://dx.doi.org/10.1103/physrevb.51.7325.

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Ota, Yukihiro, et Ichiro Ohba. « Crossover from Classical to Quantum Behavior in Duffing Oscillator through “Pseudo-Lyapunov Exponent” ». Journal of the Physical Society of Japan 72, Suppl.C (janvier 2003) : 119–22. http://dx.doi.org/10.1143/jpsjs.72sc.119.

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Zeng, Gang-hui, Yang Zhang, Aleksey N. Bolgar, Dong He, Bin Li, Xin-hui Ruan, Lan Zhou et al. « Quantum versus classical regime in circuit quantum acoustodynamics ». New Journal of Physics 23, n^o 12 (1 décembre 2021) : 123001. http://dx.doi.org/10.1088/1367-2630/ac3555.

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Abstract We experimentally study a circuit quantum acoustodynamics system with a superconducting artificial atom coupled to both a two-dimensional surface acoustic wave resonator and a one-dimensional microwave transmission line. The strong coupling between the artificial atom and the acoustic wave resonator is confirmed by the observation of the vacuum Rabi splitting at the base temperature of dilution refrigerator. We show that the propagation of microwave photons in the microwave transmission line can be controlled by a few phonons in the acoustic wave resonator. Furthermore, we demonstrate the temperature effect on the measurements of the Rabi splitting and temperature induced transitions from high excited dressed states. We find that the spectrum structure of two-peak for the Rabi splitting could become into those of several peaks under some special experimental conditions, and gradually disappears with the increase of the environmental temperature T. The continuous quantum-to-classical crossover is observed around the crossover temperature T c, which is determined via the thermal fluctuation energy k B T and the characteristic energy level spacing of the coupled system. Experimental results agree well with the theoretical simulations via the master equation of the coupled system at different effective temperatures.

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RUGGIERO, B., V. CORATO, E. ESPOSITO, C. GRANATA, M. RUSSO, P. SILVESTRINI et L. STODOLSKY. « MACROSCOPIC QUANTUM COHERENCE IN JOSEPHSON SYSTEMS ». International Journal of Modern Physics B 14, n^o 25n27 (30 octobre 2000) : 3050–55. http://dx.doi.org/10.1142/s0217979200003290.

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We present our recent experiments on macroscopic tunneling in the quantum regime for underdamped Josephson junctions with different classical-quantum crossover temperatures. These experiments are performed towards the observation of macroscopic quantum coherence in Josephson systems. A new method to measure coherence in a two-level system based on the adiabatic inversion in an rf squid, is presented. This approach could open new perspectives in view of realization of an elementary quantum bit.

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31

Duan, Ji-Min. « Comment on ‘‘Classical-to-quantum crossover in charge-density wave creep at low temperatures’’ ». Physical Review Letters 72, n^o 4 (24 janvier 1994) : 586. http://dx.doi.org/10.1103/physrevlett.72.586.

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Dereka, Bogdan, Qi Yu, Nicholas H. C. Lewis, William B. Carpenter, Joel M. Bowman et Andrei Tokmakoff. « Crossover from hydrogen to chemical bonding ». Science 371, n^o 6525 (7 janvier 2021) : 160–64. http://dx.doi.org/10.1126/science.abe1951.

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Hydrogen bonds (H-bonds) can be interpreted as a classical electrostatic interaction or as a covalent chemical bond if the interaction is strong enough. As a result, short strong H-bonds exist at an intersection between qualitatively different bonding descriptions, with few experimental methods to understand this dichotomy. The [F-H-F]− ion represents a bare short H-bond, whose distinctive vibrational potential in water is revealed with femtosecond two-dimensional infrared spectroscopy. It shows the superharmonic behavior of the proton motion, which is strongly coupled to the donor-acceptor stretching and disappears on H-bond bending. In combination with high-level quantum-chemical calculations, we demonstrate a distinct crossover in spectroscopic properties from conventional to short strong H-bonds, which identify where hydrogen bonding ends and chemical bonding begins.

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Chisholm, Dario A., Guillermo García-Pérez, Matteo A. C. Rossi, Sabrina Maniscalco et G. Massimo Palma. « Witnessing objectivity on a quantum computer ». Quantum Science and Technology 7, n^o 1 (23 décembre 2021) : 015022. http://dx.doi.org/10.1088/2058-9565/ac40f3.

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Abstract Understanding the emergence of objectivity from the quantum realm has been a long standing issue strongly related to the quantum to classical crossover. Quantum Darwinism (QD) provides an answer, interpreting objectivity as consensus between independent observers. Quantum computers provide an interesting platform for such experimental investigation of QD, fulfiling their initial intended purpose as quantum simulators. Here we assess to what degree current Noisy intermediate-scale quantum devices can be used as experimental platforms in the field of QD. We do this by simulating an exactly solvable stochastic collision model, taking advantage of the analytical solution to benchmark the experimental results.

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EVERITT, M. J. « NON-LINEAR DYNAMICS, ENTANGLEMENT AND THE QUANTUM-CLASSICAL CROSSOVER OF TWO COUPLED SQUID RINGS ». International Journal of Modern Physics B 23, n^o 20n21 (20 août 2009) : 4311–19. http://dx.doi.org/10.1142/s0217979209063468.

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We explore the quantum-classical crossover of two coupled, identical, superconducting quantum interference device (SQUID) rings. We note that the motivation for this work is based on a study of a similar system comprising two coupled Duffing oscillators. In that work we showed that the entanglement characteristics of chaotic and periodic (entrained) solutions differed significantly and that in the classical limit entanglement was preserved only in the chaotic-like solutions. However, Duffing oscillators are a highly idealised toy model. Motivated by a wish to explore more experimentally realisable systems we now extend our work to an analysis of two coupled SQUID rings. We observe some differences in behaviour between the system that is based on SQUID rings rather than on Duffing oscillators. However, we show that the two systems share a common feature. That is, even when the SQUID ring's trajectories appear to follow (semi) classical orbits entanglement persists.

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Kasprzak, J., K. Sivalertporn, F. Albert, C. Schneider, S. Höfling, M. Kamp, A. Forchel, S. Reitzenstein, E. A. Muljarov et W. Langbein. « Coherence dynamics and quantum-to-classical crossover in an exciton–cavity system in the quantum strong coupling regime ». New Journal of Physics 15, n^o 4 (22 avril 2013) : 045013. http://dx.doi.org/10.1088/1367-2630/15/4/045013.

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SHRESTHA, R. K., W. K. LAM, J. NI et G. S. SUMMY. « A COLD-ATOM RATCHET INTERPOLATING BETWEEN CLASSICAL AND QUANTUM DYNAMICS ». Fluctuation and Noise Letters 12, n^o 02 (juin 2013) : 1340003. http://dx.doi.org/10.1142/s0219477513400038.

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We use an atomic ratchet realized by applying short pulses of an optical standing-wave to a Bose–Einstein condensate to study the crossover between classical and quantum dynamics. The signature of the ratchet is the existence of a directed current of atoms, even though there is an absence of a net bias force. Provided that the pulse period is close to one of the resonances of the system, the ratchet behavior can be understood using a classical like theory which depends on a single variable containing many of the experimental parameters. Here we show that this theory is valid in both the true classical limit, when the pulse period is close to zero, as well as regimes when this period is close to other resonances where the usual scaled Planck's constant is nonzero. By smoothly changing the pulse period between these resonances we demonstrate how it is possible to tune the ratchet between quantum and classical types of behavior.

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Yamada, Masaki, et Satoshi Tanda. « Observation of the crossover from quantum to classical critical behavior in ferromagnetic alloys of Pd1−xNix ». Physica B : Condensed Matter 281-282 (juin 2000) : 384–85. http://dx.doi.org/10.1016/s0921-4526(99)01075-3.

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Zhang, Chao, et P. C. E. Stamp. « Diffusion of objects in superconductors : crossover from classical to quantum behaviour on suppression of infrared couplings ». Journal of Physics : Condensed Matter 4, n^o 42 (19 octobre 1992) : L549—L554. http://dx.doi.org/10.1088/0953-8984/4/42/002.

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Carabba, Nicoletta, Niklas Hörnedal et Adolfo del Campo. « Quantum speed limits on operator flows and correlation functions ». Quantum 6 (22 décembre 2022) : 884. http://dx.doi.org/10.22331/q-2022-12-22-884.

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Quantum speed limits (QSLs) identify fundamental time scales of physical processes by providing lower bounds on the rate of change of a quantum state or the expectation value of an observable. We introduce a generalization of QSL for unitary operator flows, which are ubiquitous in physics and relevant for applications in both the quantum and classical domains. We derive two types of QSLs and assess the existence of a crossover between them, that we illustrate with a qubit and a random matrix Hamiltonian, as canonical examples. We further apply our results to the time evolution of autocorrelation functions, obtaining computable constraints on the linear dynamical response of quantum systems out of equilibrium and the quantum Fisher information governing the precision in quantum parameter estimation.

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PARK, CHANG-SOO. « FIRST- AND SECOND-ORDER CROSSOVERS OF SPIN TUNNELING IN Mn12-ACETATE MOLECULAR MAGNET WITH FOURTH-ORDER ANISOTROPY ». Modern Physics Letters B 16, n^o 15n16 (10 juillet 2002) : 555–67. http://dx.doi.org/10.1142/s021798490200410x.

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We have studied the escape rate of spin tunneling in a molecular magnet with a fourfold easy axis, such as Mn 12-acetate, in the presence of an external field applied perpendicular to the easy axis. Both perturbation theory and numerical diagonalization have been used to investigate the type of quantum-classical crossover and the crossover temperature T c . We have observed that T c ~ 1.2 K which agrees with experimental results,9 and the first-order region increases due to the fourth-order transverse anisotropy. More interestingly, when the field is applied along the hard axis, first- and second-order regions alternate as the field increases.

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Amini, M., V. E. Kravtsov et M. Müller. « Multifractality and quantum-to-classical crossover in the Coulomb anomaly at the Mott–Anderson metal–insulator transition ». New Journal of Physics 16, n^o 1 (17 janvier 2014) : 015022. http://dx.doi.org/10.1088/1367-2630/16/1/015022.

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Larkin1, A. I., et Yu N. Ovchinnikov. « The crossover from classical to quantum regime in the problem of the decay of the metastable state ». Journal of Statistical Physics 41, n^o 3-4 (novembre 1985) : 425–43. http://dx.doi.org/10.1007/bf01009016.

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Gadomski, Adam, et Natalia Kruszewska. « Matter-Aggregating Low-Dimensional Nanostructures at the Edge of the Classical vs. Quantum Realm ». Entropy 25, n^o 1 (20 décembre 2022) : 1. http://dx.doi.org/10.3390/e25010001.

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This commentary tackles the subtle at-the-edge problem of passing locally by a mesoscopic matter-aggregating system from a classical stochastic to a quantum stochastic description. A d-dimensional entropy-productive aggregation of the matter is taken as the starting point. Then, a dimensional reduction towards a one-dimensional quantum-wire type matter-aggregation system is proposed, resulting in postponing surface-tension conditions for the effectively d = 1-dimensional quantum-wire type or nanorod-like cluster/polycrystal, which is qualitatively consistent with a physical-metallurgical (high-temperature) Louat’s grain growth model. A certain recuperative interplay based on maneuvering between subtle temperature rises applied to the system under study while maintaining its quantum character (the so-called Nelson’s quantum-stochastic procedure) within the limits of a vanishing Planck’s constant, involved in the diffusivity measure of the aggregation, is discussed. Certain applications towards the formation of d = 1-dimensional semiconductors and other nanostructures (possibly using soft materials or (bio)polymeric materials such as nanofibers) are envisioned. As a special example, one may propose a nanotechnological process which is termed the Van der Waals heteroepitaxy. The process itself contains the main quantum vs. classical crossover due to the involvement of weak repulsion (quantum) vs. attraction (treated classically) interactions, which are represented by a Lennard-Jones-type potential.

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TOMASELLO, BRUNO, DAVIDE ROSSINI, ALIOSCIA HAMMA et LUIGI AMICO. « QUANTUM DISCORD IN A SPIN SYSTEM WITH SYMMETRY BREAKING ». International Journal of Modern Physics B 26, n^o 27n28 (18 septembre 2012) : 1243002. http://dx.doi.org/10.1142/s0217979212430023.

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We analyze the quantum discordQ throughout the low temperature phase diagram of the quantum XY model in transverse field. We first focus on the T = 0 order–disorder quantum phase transition QPT both in the symmetric ground state and in the symmetry broken one. Beside it, we highlight how Q displays clear anomalies also at a noncritical value of the control parameter inside the ordered phase, where the ground state is completely factorized. We evidence how the phenomenon is in fact of collective nature and displays universal features. We also study Q at finite temperature. We show that, close to the QPT, Q exhibits quantum-classical crossover of the system with universal scaling behavior. We evidence a nontrivial pattern of thermal correlations resulting from the factorization phenomenon.

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DUAN, HAI-BIN, CHUN-FANG XU et ZHI-HUI XING. « A HYBRID ARTIFICIAL BEE COLONY OPTIMIZATION AND QUANTUM EVOLUTIONARY ALGORITHM FOR CONTINUOUS OPTIMIZATION PROBLEMS ». International Journal of Neural Systems 20, n^o 01 (février 2010) : 39–50. http://dx.doi.org/10.1142/s012906571000222x.

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In this paper, a novel hybrid Artificial Bee Colony (ABC) and Quantum Evolutionary Algorithm (QEA) is proposed for solving continuous optimization problems. ABC is adopted to increase the local search capacity as well as the randomness of the populations. In this way, the improved QEA can jump out of the premature convergence and find the optimal value. To show the performance of our proposed hybrid QEA with ABC, a number of experiments are carried out on a set of well-known Benchmark continuous optimization problems and the related results are compared with two other QEAs: the QEA with classical crossover operation, and the QEA with 2-crossover strategy. The experimental comparison results demonstrate that the proposed hybrid ABC and QEA approach is feasible and effective in solving complex continuous optimization problems.

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Granata, C., E. Esposito, B. Ruggiero, M. Russo et P. Silvestrini. « Macroscopic Quantum Tunneling in Josephson Junctions and Squids ». International Journal of Modern Physics B 13, n^o 09n10 (20 avril 1999) : 1271–76. http://dx.doi.org/10.1142/s0217979299001296.

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We report experiments on energy level quantization in Nb/AlOx/Nb Josephson junctions while measurements on SQUIDs are in progress. Data on the presence of energy level quantization are shown at temperatures above the classical-quantum regime crossover temperature. This has been possible by extending the measurements of the rate of the escape from the zero-voltage state at higher sweep bias rate in order to induce non-stationary conditions in the energy potential describing the junction dynamics. Data are compatible with extremely low "effective" dissipation in our system. Theoretical predictions on quantum effects related to the presence of non-stationary conditions in the potential associated to a rf SQUID are reported in view of new possible experiments.

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Orlita, M., I. Crassee, C. Faugeras, A. B. Kuzmenko, F. Fromm, M. Ostler, Th Seyller, G. Martinez, M. Polini et M. Potemski. « Classical to quantum crossover of the cyclotron resonance in graphene : a study of the strength of intraband absorption ». New Journal of Physics 14, n^o 9 (10 septembre 2012) : 095008. http://dx.doi.org/10.1088/1367-2630/14/9/095008.

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Pradler, Josef, et Lukas Semmelrock. « Nonrelativistic Electron–Ion Bremsstrahlung : An Approximate Formula for All Parameters ». Astrophysical Journal 922, n^o 1 (1 novembre 2021) : 57. http://dx.doi.org/10.3847/1538-4357/ac24a8.

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Abstract The evaluation of the electron–ion bremsstrahlung cross section—exact to all orders in the Coulomb potential—is computationally expensive due to the appearance of hypergeometric functions. Therefore, tabulations are widely used. Here, we provide an approximate formula for the nonrelativistic dipole process valid for all applicable relative velocities and photon energies. Its validity spans from the Born to the classical regime and from soft-photon emission to the kinematic endpoint. The error remains below 3% (and widely below 1%) except at an isolated region of hard-photon emission at the quantum-to-classical crossover. We use the formula to obtain the thermally averaged emission spectrum and cooling function in a Maxwellian plasma and demonstrate that they are accurate to better than 2%.

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LONGOBARDI, L., V. CORATO, C. GRANATA, S. ROMBETTO, M. RUSSO, B. RUGGIERO et P. SILVESTRINI. « RF SQUID BASED DEVICES FOR MQC ». International Journal of Modern Physics B 17, n^o 04n06 (10 mars 2003) : 762–67. http://dx.doi.org/10.1142/s0217979203016571.

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We present different types of integrated planar SQUID devices in view of Macroscopic Quantum Coherence (MQC) experiments. These devices include an rf SQUID as a probe to test the MQC, coupled to a readout system based on a dc SQUID sensor. Both dc SQUID and flux transformer are in a gradiometric configuration to minimize the electromagnetic noise from environment. We report data on dc SQUID performances as well as preliminary results on the decay from the metastable flux state for rf SQUID-based devices above the crossover temeperature (classical limit).

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Xie, Weiwei, Daniel Holub, Tomáš Kubař et Marcus Elstner. « Performance of Mixed Quantum-Classical Approaches on Modeling the Crossover from Hopping to Bandlike Charge Transport in Organic Semiconductors ». Journal of Chemical Theory and Computation 16, n^o 4 (16 mars 2020) : 2071–84. http://dx.doi.org/10.1021/acs.jctc.9b01271.

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