Faster State Preparation across Quantum Phase Transition Assisted by Reinforcement Learning
| Autor: | Shuai-Feng Guo, Li You, Jia-Hao Cao, Jun-Jie Chen, Meng Khoon Tey, Qi Liu, Tian-Wei Mao, Feng Chen, Ming Xue |
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| Rok vydání: | 2020 |
| Předmět: |
Quantum phase transition
Physics Quantum Physics Quantum dynamics General Physics and Astronomy FOS: Physical sciences 01 natural sciences Quantum state Quantum Gases (cond-mat.quant-gas) Quantum critical point Quantum mechanics Excited state 0103 physical sciences Sensitivity (control systems) Condensed Matter - Quantum Gases 010306 general physics Ground state Adiabatic process Quantum Physics (quant-ph) |
| DOI: | 10.48550/arxiv.2011.11987 |
| Popis: | An energy gap develops near quantum critical point of quantum phase transition in a finite many-body (MB) system, facilitating the ground state transformation by adiabatic parameter change. In real application scenarios, however, the efficacy for such a protocol is compromised by the need to balance finite system life time with adiabaticity, as exemplified in a recent experiment that prepares three-mode balanced Dicke state near deterministically [PNAS {\bf 115}, 6381 (2018)]. Instead of tracking the instantaneous ground state as unanimously required for most adiabatic crossing, this work reports a faster sweeping policy taking advantage of excited level dynamics. It is obtained based on deep reinforcement learning (DRL) from a multi-step training scheme we develop. In the absence of loss, a fidelity $\ge 99\%$ between prepared and the target Dicke state is achieved over a small fraction of the adiabatically required time. When loss is included, training is carried out according to an operational benchmark, the interferometric sensitivity of the prepared state instead of fidelity, leading to better sensitivity in about half of the previously reported time. Implemented in a Bose-Einstein condensate of $\sim 10^4$ $^{87}$Rb atoms, the balanced three-mode Dicke state exhibiting an improved number squeezing of $13.02\pm0.20$ dB is observed within 766 ms, highlighting the potential of DRL for quantum dynamics control and quantum state preparation in interacting MB systems. Comment: 6 + 11 pages, 3 + 8 figures |
| Databáze: | OpenAIRE |
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