Witnessing objectivity on a quantum computer

Chisholm, Dario A.; García-Pérez, Guillermo; Rossi, Matteo A. C.; Maniscalco, Sabrina; Palma, G. Massimo

doi:10.1088/2058-9565/ac40f3

Cited by 11 publications

(4 citation statements)

References 43 publications

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“…The relative entropy is defined according to [46] S(ρ, σ) = Tr ρ log ρ − Tr ρ log σ, (13) so that when used to quantify correlations it leads to the mutual information…”

Section: A Quantifiers Of Correlationsmentioning

confidence: 99%

“…These correlations are the basis for notions of classical objectivity [3][4][5][6][7] and are also known to play a key role in the characterisation of the dynamics, in particular, if the system undergoes a Markovian (memoryless) or non-Markovian evolution [8,9]. Both notions of classical objectivity and non-Markovian evolution have been the object of experimental investigations, see for example [10][11][12][13] and [14][15][16][17][18][19][20] respectively.…”

Section: Introductionmentioning

confidence: 99%

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Correlations, information backflow, and objectivity in a class of pure dephasing models

Megier,

Smirne,

Campbell

et al. 2022

Preprint

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We critically examine the role that correlations established between a system and fragments of its environment play in characterising the ensuing dynamics. We employ a class of dephasing models where the state of the initial environment represents a tunable degree of freedom that qualitatively and quantitatively affects the correlation profiles, but nevertheless results in the same reduced dynamics for the system. We apply recently developed tools for the characterisation of non-Markovianity to carefully assess the role that correlations, as quantified by the (quantum) Jensen-Shannon divergence and relative entropy, as well as changes in the environmental state, play in whether the conditions for classical objectivity within the quantum Darwinism paradigm are met. We demonstrate that for precisely the same non-Markovian reduced dynamics of the system arising from different microscopic models, some will exhibit quantum Darwinistic features, while others show no meaningful notion of classical objectivity is present. Furthermore, our results highlight that the non-Markovian nature of an environment does not a priori prevent a system from redundantly proliferating relevant information, but rather it is the system's ability to establish the requisite correlations that is the crucial factor in the manifestation of classical objectivity.

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“…The relative entropy is defined according to [46] S(ρ, σ) = Tr ρ log ρ − Tr ρ log σ, (13) so that when used to quantify correlations it leads to the mutual information…”

Section: A Quantifiers Of Correlationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Correlations, information backflow, and objectivity in a class of pure dephasing models

Megier,

Smirne,

Campbell

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…These correlations are the basis for notions of classical objectivity [ 3 , 4 , 5 , 6 , 7 ] and are also known to play a key role in the characterisation of the dynamics, in particular, if the system undergoes a Markovian (memoryless) or non-Markovian evolution [ 8 , 9 ]. Both notions of classical objectivity and non-Markovian evolution have been the object of experimental investigations; see, for example, [ 10 , 11 , 12 , 13 ] and [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ], respectively.…”

Section: Introductionmentioning

confidence: 99%

Correlations, Information Backflow, and Objectivity in a Class of Pure Dephasing Models

Megier

Smirne

Campbell

et al. 2022

Entropy

View full text Add to dashboard Cite

We critically examine the role that correlations established between a system and fragments of its environment play in characterising the ensuing dynamics. We employ a dephasing model with different initial conditions, where the state of the initial environment represents a tunable degree of freedom that qualitatively and quantitatively affects the correlation profiles, but nevertheless results in the same reduced dynamics for the system. We apply recently developed tools for the characterisation of non-Markovianity to carefully assess the role that correlations, as quantified by the (quantum) Jensen–Shannon divergence and relative entropy, as well as changes in the environmental state, play in whether the conditions for classical objectivity within the quantum Darwinism paradigm are met. We demonstrate that for precisely the same non-Markovian reduced dynamics of the system arising from different microscopic models, some exhibit quantum Darwinistic features, while others show that no meaningful notion of classical objectivity is present. Furthermore, our results highlight that the non-Markovian nature of an environment does not a priori prevent a system from redundantly proliferating relevant information, but rather it is the system’s ability to establish the requisite correlations that is the crucial factor in the manifestation of classical objectivity.

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“…Currently available quantum computation platforms belong to the class of noisy intermediate-scale devices [5][6][7]. Nevertheless, these machines constitute intriguing systems for conducting proof-of-principle studies, for testing the efficient implementation of quantum algorithms and for making conceptual progress in the understanding of the utility of quantum computers [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

mentioning

confidence: 99%

Thermodynamics of Quantum Trajectories on a Quantum Computer

Cech,

Lesanovsky,

Carollo

2023

Phys. Rev. Lett.

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Quantum computers have recently become available as noisy intermediate-scale quantum devices. Already these machines yield a useful environment for research on quantum systems and dynamics. Building on this opportunity, we investigate open-system dynamics that are simulated on a quantum computer by coupling a system of interest to an ancilla. After each interaction the ancilla is measured and the sequence of measurements defines a quantum trajectory. Using a thermodynamic analogy, which identifies trajectories as microstates, we show how to bias the dynamics of the open system in order to enhance the probability of quantum trajectories with desired properties, e.g., particular measurement patterns or temporal correlations. We discuss how such a biased -generally non-Markovian -dynamics can be implemented on a unitary, gate-based quantum computer and show proof-of-principle results on the publicly accessible ibmq jakarta machine. While our study is solely conducted on small systems, it highlights the challenges in controlling complex aspects of open-system dynamics on digital quantum computers.

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Witnessing objectivity on a quantum computer

Cited by 11 publications

References 43 publications

Correlations, information backflow, and objectivity in a class of pure dephasing models

Correlations, information backflow, and objectivity in a class of pure dephasing models

Correlations, Information Backflow, and Objectivity in a Class of Pure Dephasing Models

Thermodynamics of Quantum Trajectories on a Quantum Computer

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