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Zhang ZY, Sun Z, Duan T, Ding YK, Huang X, Liu JM. Entanglement Generation of Polar Molecules via Deep Reinforcement Learning. J Chem Theory Comput 2024; 20:1811-1820. [PMID: 38320113 DOI: 10.1021/acs.jctc.3c01214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Polar molecules are a promising platform for achieving scalable quantum information processing because of their long-range electric dipole-dipole interactions. Here, we take the coupled ultracold CaF molecules in an external electric field with gradient as qubits and concentrate on the creation of intermolecular entanglement with the method of deep reinforcement learning (RL). After sufficient training episodes, the educated RL agents can discover optimal time-dependent control fields that steer the molecular systems from separate states to two-qubit and three-qubit entangled states with high fidelities. We analyze the fidelities and the negativities (characterizing entanglement) of the generated states as a function of training episodes. Moreover, we present the population dynamics of the molecular systems under the influence of control fields discovered by the agents. Compared with the schemes for creating molecular entangled states based on optimal control theory, some conditions (e.g., molecular spacing and electric field gradient) adopted in this work are more feasible in the experiment. Our results demonstrate the potential of machine learning to effectively solve quantum control problems in polar molecular systems.
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Affiliation(s)
- Zuo-Yuan Zhang
- School of Physical Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Zhaoxi Sun
- Changping Laboratory, Beijing 102206, China
| | - Tao Duan
- State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China
| | - Yi-Kai Ding
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Xinning Huang
- School of Physical Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Jin-Ming Liu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
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Gong T, Ji Z, Du J, Zhao Y, Xiao L, Jia S. Microwave-assisted coherent control of ultracold polar molecules in a ladder-type configuration of rotational states. Phys Chem Chem Phys 2021; 23:4271-4276. [PMID: 33587738 DOI: 10.1039/d1cp00202c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate microwave-assisted coherent control of ultracold 85Rb133Cs molecules in a ladder-type configuration of rotational states. Specifically, we use a probe and a control MW field to address the transitions between the J = 1 → 2 and J = 2 → 3 rotational states of the X1Σ+(v = 0) vibrational level, respectively, and use the control field to modify the response of the probe MW transition by coherently reducing the population of the intermediate J = 2 state. We observe that an increased Rabi frequency of the control field leads to broadening of the probe spectrum splitting and a shift of the central frequency. We apply Akaike's information criterion (AIC) to conclude that the observed coherent spectral response appears across the crossover regime between electromagnetically induced transparency and Aulter-Townes splitting. Our work is a significant development in microwave-assisted quantum control of ultracold polar molecules with multilevel configuration.
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Affiliation(s)
- Ting Gong
- Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Wucheng Rd 92, 030006 Taiyuan, China. and Shanxi University, Collaborative Innovation Center of Extreme Optics, Wucheng Rd 92, 030006 Taiyuan, China
| | - Zhonghua Ji
- Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Wucheng Rd 92, 030006 Taiyuan, China. and Shanxi University, Collaborative Innovation Center of Extreme Optics, Wucheng Rd 92, 030006 Taiyuan, China
| | - Jiaqi Du
- Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Wucheng Rd 92, 030006 Taiyuan, China. and Shanxi University, Collaborative Innovation Center of Extreme Optics, Wucheng Rd 92, 030006 Taiyuan, China
| | - Yanting Zhao
- Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Wucheng Rd 92, 030006 Taiyuan, China. and Shanxi University, Collaborative Innovation Center of Extreme Optics, Wucheng Rd 92, 030006 Taiyuan, China
| | - Liantuan Xiao
- Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Wucheng Rd 92, 030006 Taiyuan, China. and Shanxi University, Collaborative Innovation Center of Extreme Optics, Wucheng Rd 92, 030006 Taiyuan, China
| | - Suotang Jia
- Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Wucheng Rd 92, 030006 Taiyuan, China. and Shanxi University, Collaborative Innovation Center of Extreme Optics, Wucheng Rd 92, 030006 Taiyuan, China
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Blackmore JA, Gregory PD, Bromley SL, Cornish SL. Coherent manipulation of the internal state of ultracold 87Rb 133Cs molecules with multiple microwave fields. Phys Chem Chem Phys 2020; 22:27529-27538. [PMID: 33079114 DOI: 10.1039/d0cp04651e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We explore coherent multi-photon processes in 87Rb133Cs molecules using 3-level lambda and ladder configurations of rotational and hyperfine states, and discuss their relevance to future applications in quantum computation and quantum simulation. In the lambda configuration, we demonstrate the driving of population between two hyperfine levels of the rotational ground state via a two-photon Raman transition. Such pairs of states may be used in the future as a quantum memory, and we measure a Ramsey coherence time for a superposition of these states of 58(9) ms. In the ladder configuration, we show that we can generate and coherently populate microwave dressed states via the observation of an Autler-Townes doublet. We demonstrate that we can control the strength of this dressing by varying the intensity of the microwave coupling field. Finally, we perform spectroscopy of the rotational states of 87Rb133Cs up to N = 6, highlighting the potential of ultracold molecules for quantum simulation in synthetic dimensions. By fitting the measured transition frequencies we determine a new value of the centrifugal distortion coefficient Dv = h × 207.3(2) Hz.
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Affiliation(s)
- Jacob A Blackmore
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK.
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