Modified quantum regression theorem and consistency with Kubo-Martin-Schwinger condition
We show that the long-time limit of the two-point correlation function obtained via the standard quantum regression theorem (QRT), a standard tool to compute correlation functions in open quantum systems, does not respect the Kubo–Martin–Schwinger equilibrium condition to the non-zero order of the s...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/ad976f |
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| author | Sakil Khan Bijay Kumar Agarwalla Sachin Jain |
| author_facet | Sakil Khan Bijay Kumar Agarwalla Sachin Jain |
| author_sort | Sakil Khan |
| collection | DOAJ |
| description | We show that the long-time limit of the two-point correlation function obtained via the standard quantum regression theorem (QRT), a standard tool to compute correlation functions in open quantum systems, does not respect the Kubo–Martin–Schwinger equilibrium condition to the non-zero order of the system-bath coupling. We then follow the recently developed Heisenberg operator method for open quantum systems and by applying a ‘ weak ’ Markov approximation, derive a new modified version of the QRT that not only respects the KMS condition but further predicts exact answers for certain paradigmatic models in specific limits. We also show that in cases where the modified QRT does not match with exact answers, it always performs better than the standard QRT. |
| format | Article |
| id | doaj-art-50f0ca1b9e264d85bd7cc1a3720a7895 |
| institution | DOAJ |
| issn | 1367-2630 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj-art-50f0ca1b9e264d85bd7cc1a3720a78952025-08-20T02:39:24ZengIOP PublishingNew Journal of Physics1367-26302024-01-01261212301110.1088/1367-2630/ad976fModified quantum regression theorem and consistency with Kubo-Martin-Schwinger conditionSakil Khan0Bijay Kumar Agarwalla1Sachin Jain2Department of Physics, Indian Institute of Science Education and Research , Pune 411008, IndiaDepartment of Physics, Indian Institute of Science Education and Research , Pune 411008, IndiaDepartment of Physics, Indian Institute of Science Education and Research , Pune 411008, IndiaWe show that the long-time limit of the two-point correlation function obtained via the standard quantum regression theorem (QRT), a standard tool to compute correlation functions in open quantum systems, does not respect the Kubo–Martin–Schwinger equilibrium condition to the non-zero order of the system-bath coupling. We then follow the recently developed Heisenberg operator method for open quantum systems and by applying a ‘ weak ’ Markov approximation, derive a new modified version of the QRT that not only respects the KMS condition but further predicts exact answers for certain paradigmatic models in specific limits. We also show that in cases where the modified QRT does not match with exact answers, it always performs better than the standard QRT.https://doi.org/10.1088/1367-2630/ad976fopen quantum systemmodified regression theoremthermalization |
| spellingShingle | Sakil Khan Bijay Kumar Agarwalla Sachin Jain Modified quantum regression theorem and consistency with Kubo-Martin-Schwinger condition New Journal of Physics open quantum system modified regression theorem thermalization |
| title | Modified quantum regression theorem and consistency with Kubo-Martin-Schwinger condition |
| title_full | Modified quantum regression theorem and consistency with Kubo-Martin-Schwinger condition |
| title_fullStr | Modified quantum regression theorem and consistency with Kubo-Martin-Schwinger condition |
| title_full_unstemmed | Modified quantum regression theorem and consistency with Kubo-Martin-Schwinger condition |
| title_short | Modified quantum regression theorem and consistency with Kubo-Martin-Schwinger condition |
| title_sort | modified quantum regression theorem and consistency with kubo martin schwinger condition |
| topic | open quantum system modified regression theorem thermalization |
| url | https://doi.org/10.1088/1367-2630/ad976f |
| work_keys_str_mv | AT sakilkhan modifiedquantumregressiontheoremandconsistencywithkubomartinschwingercondition AT bijaykumaragarwalla modifiedquantumregressiontheoremandconsistencywithkubomartinschwingercondition AT sachinjain modifiedquantumregressiontheoremandconsistencywithkubomartinschwingercondition |