Causal and Noncausal Revivals of Information: A New Regime of Non-Markovianity in Quantum Stochastic Processes
The study of information revivals, witnessing the violation of certain data-processing inequalities, has provided an important paradigm in the study of non-Markovian quantum stochastic processes. Although often used interchangeably, we argue here that the notions of “revivals” and “backflows,” i.e.,...
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| Format: | Article |
| Language: | English |
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American Physical Society
2025-04-01
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| Series: | PRX Quantum |
| Online Access: | http://doi.org/10.1103/PRXQuantum.6.020316 |
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| author | Francesco Buscemi Rajeev Gangwar Kaumudibikash Goswami Himanshu Badhani Tanmoy Pandit Brij Mohan Siddhartha Das Manabendra Nath Bera |
| author_facet | Francesco Buscemi Rajeev Gangwar Kaumudibikash Goswami Himanshu Badhani Tanmoy Pandit Brij Mohan Siddhartha Das Manabendra Nath Bera |
| author_sort | Francesco Buscemi |
| collection | DOAJ |
| description | The study of information revivals, witnessing the violation of certain data-processing inequalities, has provided an important paradigm in the study of non-Markovian quantum stochastic processes. Although often used interchangeably, we argue here that the notions of “revivals” and “backflows,” i.e., flows of information from the environment back into the system, are distinct: an information revival can occur without any backflow ever taking place. In this paper, we examine in detail the phenomenon of noncausal revivals and relate them to the theory of short Markov chains and squashed non-Markovianity. We also provide an operational condition, in terms of system-only degrees of freedom, to witness the presence of genuine backflow that cannot be explained by noncausal revivals. As a byproduct, we demonstrate that focusing on processes with genuine backflows, while excluding those with only noncausal revivals, resolves the issue of nonconvexity of Markovianity, thus enabling the construction of a convex resource theory of genuine quantum non-Markovianity. |
| format | Article |
| id | doaj-art-3a4668414a87401b833fa17f914bfad1 |
| institution | DOAJ |
| issn | 2691-3399 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | PRX Quantum |
| spelling | doaj-art-3a4668414a87401b833fa17f914bfad12025-08-20T03:13:25ZengAmerican Physical SocietyPRX Quantum2691-33992025-04-016202031610.1103/PRXQuantum.6.020316Causal and Noncausal Revivals of Information: A New Regime of Non-Markovianity in Quantum Stochastic ProcessesFrancesco BuscemiRajeev GangwarKaumudibikash GoswamiHimanshu BadhaniTanmoy PanditBrij MohanSiddhartha DasManabendra Nath BeraThe study of information revivals, witnessing the violation of certain data-processing inequalities, has provided an important paradigm in the study of non-Markovian quantum stochastic processes. Although often used interchangeably, we argue here that the notions of “revivals” and “backflows,” i.e., flows of information from the environment back into the system, are distinct: an information revival can occur without any backflow ever taking place. In this paper, we examine in detail the phenomenon of noncausal revivals and relate them to the theory of short Markov chains and squashed non-Markovianity. We also provide an operational condition, in terms of system-only degrees of freedom, to witness the presence of genuine backflow that cannot be explained by noncausal revivals. As a byproduct, we demonstrate that focusing on processes with genuine backflows, while excluding those with only noncausal revivals, resolves the issue of nonconvexity of Markovianity, thus enabling the construction of a convex resource theory of genuine quantum non-Markovianity.http://doi.org/10.1103/PRXQuantum.6.020316 |
| spellingShingle | Francesco Buscemi Rajeev Gangwar Kaumudibikash Goswami Himanshu Badhani Tanmoy Pandit Brij Mohan Siddhartha Das Manabendra Nath Bera Causal and Noncausal Revivals of Information: A New Regime of Non-Markovianity in Quantum Stochastic Processes PRX Quantum |
| title | Causal and Noncausal Revivals of Information: A New Regime of Non-Markovianity in Quantum Stochastic Processes |
| title_full | Causal and Noncausal Revivals of Information: A New Regime of Non-Markovianity in Quantum Stochastic Processes |
| title_fullStr | Causal and Noncausal Revivals of Information: A New Regime of Non-Markovianity in Quantum Stochastic Processes |
| title_full_unstemmed | Causal and Noncausal Revivals of Information: A New Regime of Non-Markovianity in Quantum Stochastic Processes |
| title_short | Causal and Noncausal Revivals of Information: A New Regime of Non-Markovianity in Quantum Stochastic Processes |
| title_sort | causal and noncausal revivals of information a new regime of non markovianity in quantum stochastic processes |
| url | http://doi.org/10.1103/PRXQuantum.6.020316 |
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