Dynamical phase transitions as a resource for quantum enhanced metrology
We consider the general problem of estimating an unknown control parameter of an open quantum system. We establish a direct relation between the evolution of both system and environment and the precision with which the parameter can be estimated. We show that when the open quantum system undergoes a...
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| Format: | Article |
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American Physical Society
2016
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| Online Access: | https://eprints.nottingham.ac.uk/39539/ |
| _version_ | 1848795859910656000 |
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| author | Macieszczak, Katarzyna Guţă, Mădălin Lesanovsky, Igor Garrahan, Juan P. |
| author_facet | Macieszczak, Katarzyna Guţă, Mădălin Lesanovsky, Igor Garrahan, Juan P. |
| author_sort | Macieszczak, Katarzyna |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | We consider the general problem of estimating an unknown control parameter of an open quantum system. We establish a direct relation between the evolution of both system and environment and the precision with which the parameter can be estimated. We show that when the open quantum system undergoes a first-order dynamical phase transition the quantum Fisher information (QFI), which gives the upper bound on the achievable precision of any measurement of the system and environment, becomes quadratic in observation time (cf. “Heisenberg scaling”). In fact, the QFI is identical to the variance of the dynamical observable that characterizes the phases that coexist at the transition, and enhanced scaling is a consequence of the divergence of the variance of this observable at the transition point. This identification makes it possible to establish the finite time scaling of the QFI. Near the transition the QFI is quadratic in time for times shorter than the correlation time of the dynamics. In the regime of enhanced scaling the optimal measurement whose precision is given by the QFI involves measuring both system and output. As a particular realization of these ideas, we describe a theoretical scheme for quantum enhanced estimation of an optical phase shift using the photons being emitted from a quantum system near the coexistence of dynamical phases with distinct photon emission rates. |
| first_indexed | 2025-11-14T19:38:47Z |
| format | Article |
| id | nottingham-39539 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:38:47Z |
| publishDate | 2016 |
| publisher | American Physical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-395392020-05-04T17:38:15Z https://eprints.nottingham.ac.uk/39539/ Dynamical phase transitions as a resource for quantum enhanced metrology Macieszczak, Katarzyna Guţă, Mădălin Lesanovsky, Igor Garrahan, Juan P. We consider the general problem of estimating an unknown control parameter of an open quantum system. We establish a direct relation between the evolution of both system and environment and the precision with which the parameter can be estimated. We show that when the open quantum system undergoes a first-order dynamical phase transition the quantum Fisher information (QFI), which gives the upper bound on the achievable precision of any measurement of the system and environment, becomes quadratic in observation time (cf. “Heisenberg scaling”). In fact, the QFI is identical to the variance of the dynamical observable that characterizes the phases that coexist at the transition, and enhanced scaling is a consequence of the divergence of the variance of this observable at the transition point. This identification makes it possible to establish the finite time scaling of the QFI. Near the transition the QFI is quadratic in time for times shorter than the correlation time of the dynamics. In the regime of enhanced scaling the optimal measurement whose precision is given by the QFI involves measuring both system and output. As a particular realization of these ideas, we describe a theoretical scheme for quantum enhanced estimation of an optical phase shift using the photons being emitted from a quantum system near the coexistence of dynamical phases with distinct photon emission rates. American Physical Society 2016-02-03 Article PeerReviewed Macieszczak, Katarzyna, Guţă, Mădălin, Lesanovsky, Igor and Garrahan, Juan P. (2016) Dynamical phase transitions as a resource for quantum enhanced metrology. Physical Review A, 93 (2). 022103/1-022103/10. ISSN 2469-9926 http://journals.aps.org/pra/abstract/10.1103/PhysRevA.93.022103 doi:10.1103/PhysRevA.93.022103 doi:10.1103/PhysRevA.93.022103 |
| spellingShingle | Macieszczak, Katarzyna Guţă, Mădălin Lesanovsky, Igor Garrahan, Juan P. Dynamical phase transitions as a resource for quantum enhanced metrology |
| title | Dynamical phase transitions as a resource for quantum enhanced metrology |
| title_full | Dynamical phase transitions as a resource for quantum enhanced metrology |
| title_fullStr | Dynamical phase transitions as a resource for quantum enhanced metrology |
| title_full_unstemmed | Dynamical phase transitions as a resource for quantum enhanced metrology |
| title_short | Dynamical phase transitions as a resource for quantum enhanced metrology |
| title_sort | dynamical phase transitions as a resource for quantum enhanced metrology |
| url | https://eprints.nottingham.ac.uk/39539/ https://eprints.nottingham.ac.uk/39539/ https://eprints.nottingham.ac.uk/39539/ |