Constraining work fluctuations of non-Hermitian dynamics across the exceptional point of a superconducting qubit

Fuente: arXiv
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Autores principales: Erdamar, Serra, Abbasi, Maryam, Ha, Byung, Chen, Weijian, Muldoon, Jacob, Joglekar, Yogesh, Murch, Kater W.
Formato: Preprint
Publicado: 2023
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author Erdamar, Serra
Abbasi, Maryam
Ha, Byung
Chen, Weijian
Muldoon, Jacob
Joglekar, Yogesh
Murch, Kater W.
author_facet Erdamar, Serra
Abbasi, Maryam
Ha, Byung
Chen, Weijian
Muldoon, Jacob
Joglekar, Yogesh
Murch, Kater W.
contents Thermodynamics constrains changes to the energy of a system, both deliberate and random, via its first and second laws. When the system is not in equilibrium, fluctuation theorems such as the Jarzynski equality further restrict the distributions of deliberate work done. Such fluctuation theorems have been experimentally verified in small, non-equilibrium quantum systems undergoing unitary or decohering dynamics. Yet, their validity in systems governed by a non-Hermitian Hamiltonian has long been contentious, due to the false premise of the Hamiltonian's dual and equivalent roles in dynamics and energetics. Here we show that work fluctuations in a non-Hermitian qubit obey the Jarzynski equality even if its Hamiltonian has complex or purely imaginary eigenvalues. With post-selection on a dissipative superconducting circuit undergoing a cyclic parameter sweep, we experimentally quantify the work distribution using projective energy measurements and show that the fate of the Jarzynski equality is determined by the parity-time symmetry of, and the energetics that result from, the corresponding non-Hermitian, Floquet Hamiltonian. By distinguishing the energetics from non-Hermitian dynamics, our results provide the recipe for investigating the non-equilibrium quantum thermodynamics of such open systems.
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id arxiv_https___arxiv_org_abs_2309_12393
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Constraining work fluctuations of non-Hermitian dynamics across the exceptional point of a superconducting qubit
Erdamar, Serra
Abbasi, Maryam
Ha, Byung
Chen, Weijian
Muldoon, Jacob
Joglekar, Yogesh
Murch, Kater W.
Quantum Physics
Statistical Mechanics
Thermodynamics constrains changes to the energy of a system, both deliberate and random, via its first and second laws. When the system is not in equilibrium, fluctuation theorems such as the Jarzynski equality further restrict the distributions of deliberate work done. Such fluctuation theorems have been experimentally verified in small, non-equilibrium quantum systems undergoing unitary or decohering dynamics. Yet, their validity in systems governed by a non-Hermitian Hamiltonian has long been contentious, due to the false premise of the Hamiltonian's dual and equivalent roles in dynamics and energetics. Here we show that work fluctuations in a non-Hermitian qubit obey the Jarzynski equality even if its Hamiltonian has complex or purely imaginary eigenvalues. With post-selection on a dissipative superconducting circuit undergoing a cyclic parameter sweep, we experimentally quantify the work distribution using projective energy measurements and show that the fate of the Jarzynski equality is determined by the parity-time symmetry of, and the energetics that result from, the corresponding non-Hermitian, Floquet Hamiltonian. By distinguishing the energetics from non-Hermitian dynamics, our results provide the recipe for investigating the non-equilibrium quantum thermodynamics of such open systems.
title Constraining work fluctuations of non-Hermitian dynamics across the exceptional point of a superconducting qubit
topic Quantum Physics
Statistical Mechanics
url https://arxiv.org/abs/2309.12393