Variational Quantum Metrology with Loschmidt Echo
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arXiv
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| Autori principali: | , , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2022
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| Soggetti: | |
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| _version_ | 1866916650409787392 |
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| author | Liu, Ran Wu, Ze Yang, Xiaodong Li, Yuchen Zhou, Hui Li, Zhaokai Chen, Yuquan Yuan, Haidong Peng, Xinhua |
| author_facet | Liu, Ran Wu, Ze Yang, Xiaodong Li, Yuchen Zhou, Hui Li, Zhaokai Chen, Yuquan Yuan, Haidong Peng, Xinhua |
| contents | By utilizing quantum mechanical effects, such as superposition and entanglement, quantum metrology promises higher precision than the classical strategies. It is, however, practically challenging to realize the quantum advantages. This is mainly due to the difficulties in engineering non-classical probe state and performing nontrivial measurement in practise, particularly with a large number of particles. Here we propose a scalable scheme with a symmetrical variational quantum circuit which, same as the Loschmidt echo, consists of a forward and a backward evolution. We show that in this scheme the quantum Fisher information, which quantifies the precision limit, can be efficiently obtained from a measurement signal of the Loschmidt echo. We experimentally implement the scheme on an ensemble of 10-spin quantum processor and successfully achieves a precision near the theoretical limit which outperforms the standard quantum limit with 12.4 dB. The scheme can be efficiently implemented on various noisy intermediate-scale quantum devices which provides a promising routine to demonstrate quantum advantages. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2211_12296 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Variational Quantum Metrology with Loschmidt Echo Liu, Ran Wu, Ze Yang, Xiaodong Li, Yuchen Zhou, Hui Li, Zhaokai Chen, Yuquan Yuan, Haidong Peng, Xinhua Quantum Physics By utilizing quantum mechanical effects, such as superposition and entanglement, quantum metrology promises higher precision than the classical strategies. It is, however, practically challenging to realize the quantum advantages. This is mainly due to the difficulties in engineering non-classical probe state and performing nontrivial measurement in practise, particularly with a large number of particles. Here we propose a scalable scheme with a symmetrical variational quantum circuit which, same as the Loschmidt echo, consists of a forward and a backward evolution. We show that in this scheme the quantum Fisher information, which quantifies the precision limit, can be efficiently obtained from a measurement signal of the Loschmidt echo. We experimentally implement the scheme on an ensemble of 10-spin quantum processor and successfully achieves a precision near the theoretical limit which outperforms the standard quantum limit with 12.4 dB. The scheme can be efficiently implemented on various noisy intermediate-scale quantum devices which provides a promising routine to demonstrate quantum advantages. |
| title | Variational Quantum Metrology with Loschmidt Echo |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2211.12296 |