Quantum Fisher information as a signature of the superradiant quantum phase transition
The single-mode Dicke model is well known to undergo a quantum phase transition from the so-called normal phase to the superradiant phase (hereinafter called the ‘superradiant quantum phase transition’). Normally, quantum phase transitions can be identified by the critical behavior of quantities suc...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2014-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/16/6/063039 |
| _version_ | 1797751397721047040 |
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| author | Teng-Long Wang Ling-Na Wu Wen Yang Guang-Ri Jin Neill Lambert Franco Nori |
| author_facet | Teng-Long Wang Ling-Na Wu Wen Yang Guang-Ri Jin Neill Lambert Franco Nori |
| author_sort | Teng-Long Wang |
| collection | DOAJ |
| description | The single-mode Dicke model is well known to undergo a quantum phase transition from the so-called normal phase to the superradiant phase (hereinafter called the ‘superradiant quantum phase transition’). Normally, quantum phase transitions can be identified by the critical behavior of quantities such as entanglement, quantum fluctuations, and fidelity. In this paper, we study the role of the quantum Fisher information (QFI) of both the field mode and the atoms in the ground state of the Dicke Hamiltonian. For a finite but large number of atoms, our numerical results show that near the critical atom-field coupling, the QFI of the atomic and the field subsystems can surpass their classical limits, due to the appearance of nonclassical quadrature squeezing. As the coupling increases far beyond the critical point, each subsystem becomes a highly mixed state, which degrades the QFI and hence the ultimate phase sensitivity. In the thermodynamic limit, we present the analytical results of the QFI and their relationship with the reduced variances of the field mode and the atoms. For each subsystem, we find that there is a singularity in the derivative of the QFI at the critical point, a clear signature of the quantum criticality in the Dicke model. |
| first_indexed | 2024-03-12T16:47:54Z |
| format | Article |
| id | doaj.art-c0c17b42e0054d6b90ae127a0a817899 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:47:54Z |
| publishDate | 2014-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-c0c17b42e0054d6b90ae127a0a8178992023-08-08T11:29:25ZengIOP PublishingNew Journal of Physics1367-26302014-01-0116606303910.1088/1367-2630/16/6/063039Quantum Fisher information as a signature of the superradiant quantum phase transitionTeng-Long Wang0Ling-Na Wu1Wen Yang2Guang-Ri Jin3Neill Lambert4Franco Nori5Department of Physics, Beijing Jiaotong University , Beijing 100044, Peopleʼs Republic of ChinaDepartment of Physics, Beijing Jiaotong University , Beijing 100044, Peopleʼs Republic of ChinaBeijing Computational Science Research Center , Beijing 100084, Peopleʼs Republic of ChinaDepartment of Physics, Beijing Jiaotong University , Beijing 100044, Peopleʼs Republic of ChinaAdvanced Science Institute , RIKEN, Wako-shi, Saitama 351-0198, JapanAdvanced Science Institute , RIKEN, Wako-shi, Saitama 351-0198, Japan; Department of Physics, University of Michigan , Ann Arbor, MI 48109-1040, USAThe single-mode Dicke model is well known to undergo a quantum phase transition from the so-called normal phase to the superradiant phase (hereinafter called the ‘superradiant quantum phase transition’). Normally, quantum phase transitions can be identified by the critical behavior of quantities such as entanglement, quantum fluctuations, and fidelity. In this paper, we study the role of the quantum Fisher information (QFI) of both the field mode and the atoms in the ground state of the Dicke Hamiltonian. For a finite but large number of atoms, our numerical results show that near the critical atom-field coupling, the QFI of the atomic and the field subsystems can surpass their classical limits, due to the appearance of nonclassical quadrature squeezing. As the coupling increases far beyond the critical point, each subsystem becomes a highly mixed state, which degrades the QFI and hence the ultimate phase sensitivity. In the thermodynamic limit, we present the analytical results of the QFI and their relationship with the reduced variances of the field mode and the atoms. For each subsystem, we find that there is a singularity in the derivative of the QFI at the critical point, a clear signature of the quantum criticality in the Dicke model.https://doi.org/10.1088/1367-2630/16/6/063039quantum fluctuationsquantum phase transitionsmeasurement theory42.50.Lc05.30.Rt03.65.Ta |
| spellingShingle | Teng-Long Wang Ling-Na Wu Wen Yang Guang-Ri Jin Neill Lambert Franco Nori Quantum Fisher information as a signature of the superradiant quantum phase transition New Journal of Physics quantum fluctuations quantum phase transitions measurement theory 42.50.Lc 05.30.Rt 03.65.Ta |
| title | Quantum Fisher information as a signature of the superradiant quantum phase transition |
| title_full | Quantum Fisher information as a signature of the superradiant quantum phase transition |
| title_fullStr | Quantum Fisher information as a signature of the superradiant quantum phase transition |
| title_full_unstemmed | Quantum Fisher information as a signature of the superradiant quantum phase transition |
| title_short | Quantum Fisher information as a signature of the superradiant quantum phase transition |
| title_sort | quantum fisher information as a signature of the superradiant quantum phase transition |
| topic | quantum fluctuations quantum phase transitions measurement theory 42.50.Lc 05.30.Rt 03.65.Ta |
| url | https://doi.org/10.1088/1367-2630/16/6/063039 |
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