Influence of equilibrium and nonequilibrium environments on macroscopic
realism through the Leggett-Garg inequalities
- URL: http://arxiv.org/abs/2001.09358v2
- Date: Sun, 24 May 2020 20:32:00 GMT
- Title: Influence of equilibrium and nonequilibrium environments on macroscopic
realism through the Leggett-Garg inequalities
- Authors: Kun Zhang, Wei Wu, Jin Wang
- Abstract summary: We study the macroscopic realism (macrorealism) through the two- and three-time Leggett-Garg inequalities (LGIs) in a two interacting qubits system.
We study both how the equilibrium and nonequilibrium environments influence the LGIs.
- Score: 14.326275827081577
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: We study the macroscopic realism (macrorealism) through the two- and
three-time Leggett-Garg inequalities (LGIs) in a two interacting qubits system.
The two qubits are coupled either with two bosonic (thermal or photonic) baths
or fermionic (electronic) baths. We study both how the equilibrium and
nonequilibrium environments influence the LGIs. One way to characterize the
nonequilibrium condition is by the temperature difference (for the bosonic
bath) or the chemical potential difference (for the fermionic bath). We also
study the heat or particle current and the entropy production rate generated by
the nonequilibrium environments. Analytical forms of LGIs and the maximal value
of LGIs based on the quantum master equation beyond the secular approximation
are derived. The LGI functions and the corresponding maximal value have
separated contributions, the part describing the coherent evolution and the
part describing the coupling between the system and environments. The
environment-coupling part can be from the equilibrium environment or the
nonequilibrium environment. The nonequilibrium dynamics is quantified by the
Bloch-Redfield equation which is beyond the Lindblad form. We found that the
nonequilibriumness quantified by the temperature difference or the chemical
potential difference can lead to the LGIs violations or the increase of the
maximal value of LGIs, restoring the quantum nature from certain equilibrium
cases where LGIs are preserved. The corresponding nonequilibrium thermodynamic
cost is quantified by the nonzero entropy production rate. Our finding of the
nonequilibrium promoted LGIs violations suggests a new strategy for the design
of quantum information processing and quantum computational devices to maintain
the quantum nature and quantum correlations for long.
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