Energy fluctuation relations and repeated quantum measurements

Gherardini, Stefano; Buffoni, Lorenzo; Giachetti, Guido; Trombettoni, Andrea; Ruffo, Stefano

doi:10.1016/j.chaos.2022.111890

Cited by 5 publications

(5 citation statements)

References 62 publications

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“…That is, we consider disturbing measurement schemes that do not recover the marginals over an initial and final energy measurements. In quantum thermodynamics, the best known protocol dropping assumption (1) is the celebrated TPM scheme [70,135], whereby one simply measures H(0) at the initial time and…”

Section: Circumventing the No-go Theorem For Energy Fluctuationsmentioning

confidence: 99%

Kirkwood-Dirac quasiprobability approach to quantum fluctuations: Theoretical and experimental perspectives

Lostaglio¹,

Belenchia²,

Levy³

et al. 2022

Preprint

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Recent work has revealed the central role played by the Kirkwood-Dirac quasiprobability (KDQ) as a tool to encapsulate non-classical features in the context of condensed matter physics (scrambling, dynamical phase transitions) metrology (standard and post-selected), thermodynamics (power output and fluctuation theorems), foundations (contextuality, anomalous weak values) and more. Given the growing relevance of the KDQ across the quantum sciences, the aim of this work is twofold: first, we clarify the role played by quasiprobabilities in characterising dynamical fluctuations in the presence of measurement incompatibility, and highlight how the KDQ naturally underpins and unifies quantum correlators, quantum currents, Loschmidt echoes and weak values; second, we discuss several schemes to access the KDQ and its non-classicality features, and assess their experimental feasibility in NMR and solid-state platforms. Finally, we analyze the possibility of a 'thermodynamics with quasiprobabilities' in the light of recent no-go theorems limiting traditional treatments.

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Section: Circumventing the No-go Theorem For Energy Fluctuationsmentioning

confidence: 99%

Kirkwood-Dirac quasiprobability approach to quantum fluctuations: Theoretical and experimental perspectives

Lostaglio¹,

Belenchia²,

Levy³

et al. 2022

Preprint

Self Cite

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show abstract

“…Recent technological advancements have enabled increasingly accurate and fast measurements on quantum systems [8,9]. These advances have opened up new avenues for exploring the fundamental principles of quantum mechanics [10][11][12] and have led to the development of novel applications in fields such as quantum information processing [13,14] and quantum thermodynamics [15][16][17][18][19][20][21][22][23]. However, the dynamics of continuously monitored quantum systems are often difficult to analyze, and there is a need for theoretical approaches that can provide insights into the behavior of these systems Great interest has been shown in measurement-induced criticality, which has emerged as a prominent topic in the study of continuously monitored quantum systems .…”

Section: Introductionmentioning

confidence: 99%

“…Figure 2.Upper panels: the time-dependent probability distribution Pσz (x; t) for a two-level system (Ω = 1). The white continuous line represents the no-click contribution P (0) (x; t) in equation(21). We set γ = 0.2 (left), γ = 2.0 (center) and γ = 5.0 (right).…”

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confidence: 99%

Continuously monitored quantum systems beyond Lindblad dynamics

Lami,

Santini,

Collura

2024

New J. Phys.

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The dynamics of a quantum system, undergoing unitary evolution andcontinuous monitoring, can be described in term of quantum trajectories. Although theaveraged state fully characterises expectation values, the entire ensamble of stochastictrajectories goes beyond simple linear observables, keeping a more attentive descriptionof the entire dynamics. Here we go beyond the Lindblad dynamics and study theprobability distribution of the expectation value of a given observable over the possiblequantum trajectories. The measurements are applied to the entire system, having theeffect of projecting the system into a product state. We develop an analytical toolto evaluate this probability distribution at any time $t$. We illustrate our approachby analyzing two paradigmatic examples: a single qubit subjected to magnetizationmeasurements, and a free hopping particle subjected to position measurements.

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“…In this regard, fluctuation relations and the statistics of thermodynamic quantities in unital quantum maps have been studied for instance in [ 12 – 14 ]. It is worth mentioning in particular the case of unitary dynamics interspersed by projective measurements that also belong to this class [ 15 – 20 ].…”

Section: Introductionmentioning

confidence: 99%

Stochastic Entropy Production: Fluctuation Relation and Irreversibility Mitigation in Non-unital Quantum Dynamics

2023

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In this work, we study the stochastic entropy production in open quantum systems whose time evolution is described by a class of non-unital quantum maps. In particular, as in Phys Rev E 92:032129 (2015), we consider Kraus operators that can be related to a nonequilibrium potential. This class accounts for both thermalization and equilibration to a non-thermal state. Unlike unital quantum maps, non-unitality is responsible for an unbalance of the forward and backward dynamics of the open quantum system under scrutiny. Here, concentrating on observables that commute with the invariant state of the evolution, we show how the non-equilibrium potential enters the statistics of the stochastic entropy production. In particular, we prove a fluctuation relation for the latter and we find a convenient way of expressing its average solely in terms of relative entropies. Then, the theoretical results are applied to the thermalization of a qubit with non-Markovian transient, and the phenomenon of irreversibility mitigation, introduced in Phys Rev Res 2:033250 (2020), is analyzed in this context.

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Energy fluctuation relations and repeated quantum measurements

Cited by 5 publications

References 62 publications

Kirkwood-Dirac quasiprobability approach to quantum fluctuations: Theoretical and experimental perspectives

Kirkwood-Dirac quasiprobability approach to quantum fluctuations: Theoretical and experimental perspectives

Continuously monitored quantum systems beyond Lindblad dynamics

Stochastic Entropy Production: Fluctuation Relation and Irreversibility Mitigation in Non-unital Quantum Dynamics

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