Low‐temperature variational approximation for the Feynman quantum propagator and its application to the simulation of quantum systems

1990 ◽  
Vol 92 (12) ◽  
pp. 7531-7539 ◽  
Author(s):  
Jianshu Cao ◽  
B. J. Berne
Keyword(s):  
Low Temperature ◽  
Quantum Systems ◽  
Variational Approximation ◽  
Quantum Propagator

Propagators, Tomograms, Wavelets and Quasidistributions for Multipartite Quantum Systems

2007 ◽  
Vol 14 (02) ◽  
pp. 179-188
Author(s):  
Margarita A. Man'ko
Keyword(s):  
Degrees Of Freedom ◽  
Fractional Fourier Transform ◽  
Integral Transform ◽  
Integral Transforms ◽  
Quantum Systems ◽  
Analytic Signal ◽  
Gaussian Kernels ◽  
Quantum Propagator ◽  
System States ◽  
Mutual Relations

Integral transforms of analytic signal and quantum-system states like wavelets, tomograms, Ville-Wigner and other quasidistributions are constructed for systems with several degrees of freedom. Mutual relations of the integral transforms are presented. Quantum propagator is interpreted as the kernel of the integral transform. An example of the integral transforms with generic Gaussian kernels is studied. The fractional Fourier transform is discussed.

scholarly journals Quantum thermodynamics at low temperatures

2021 ◽  
Vol 52 (3) ◽  
pp. 15-17
Author(s):  
Jukka P. Pekola
Keyword(s):  
Quantum Information ◽  
Low Temperature ◽  
Low Temperatures ◽  
Quantum Information Processing ◽  
Quantum Systems ◽  
Quantum Thermodynamics ◽  
Heat Engines ◽  
Per Se ◽  
Working Media ◽  
Quantum Heat Engines

Low temperature phenomena and methods are quantum thermodynamics per se. Modern engineered quantum systems, for instance those used for superconducting quantum information processing and mesoscopic electron transport, provide working media for realizing devices such as quantum heat engines and refrigerators and a testbed for fundamental principles and phenomena in thermodynamics of quantum systems and processes.

scholarly journals Improved thermometry of low-temperature quantum systems by a ring-structure probe

2015 ◽  
Vol 92 (5) ◽  
Author(s):  
Li-Sha Guo ◽  
Bao-Ming Xu ◽  
Jian Zou ◽  
Bin Shao
Keyword(s):  
Low Temperature ◽  
Ring Structure ◽  
Quantum Systems

scholarly journals Thermality Versus Objectivity: Can They Peacefully Coexist?

Entropy ◽  
2021 ◽  
Vol 23 (11) ◽  
pp. 1506
Author(s):  
Thao P. Le ◽  
Andreas Winter ◽  
Gerardo Adesso
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Temperature Limit ◽  
Quantum Systems ◽  
The Other ◽  
Quantum Regime ◽  
Classical Information ◽  
High Temperature Limit ◽  
Macroscopic Objects ◽  
External Environments

Under the influence of external environments, quantum systems can undergo various different processes, including decoherence and equilibration. We observe that macroscopic objects are both objective and thermal, thus leading to the expectation that both objectivity and thermalisation can peacefully coexist on the quantum regime too. Crucially, however, objectivity relies on distributed classical information that could conflict with thermalisation. Here, we examine the overlap between thermal and objective states. We find that in general, one cannot exist when the other is present. However, there are certain regimes where thermality and objectivity are more likely to coexist: in the high temperature limit, at the non-degenerate low temperature limit, and when the environment is large. This is consistent with our experiences that everyday-sized objects can be both thermal and objective.

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