Article
Physics, Multidisciplinary
Xilin Lu, Zi-Min Li, Vladimir V. Mangazeev, Murray T. Batchelor
Summary: This study investigates the hidden Z(2) symmetry of the asymmetric quantum Rabi model (AQRM) and its generalization at specific biases, demonstrating that the symmetry operators commuting with the Hamiltonian generate a Z(2) symmetry.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Physics, Fluids & Plasmas
Ning Yu, Shiran Wang, Chunfang Sun, Gangcheng Wang
Summary: A method for investigating controllable qubit-resonator interactions in a Dicke model with driven biased term is proposed in this study, where the nonlinearity of the spectrum induced by qubit-resonator interactions plays a crucial role in controllable interactions. Nonlinearity of the transformed Hamiltonian depends on the qubit-resonator coupling strength, and general forms of effective Hamiltonians are discussed based on the frequency modulation approach. By utilizing such controllable interactions, creation of Dicke states and arbitrary superposition of Dicke states can be discussed.
Article
Materials Science, Multidisciplinary
Jiahao Yang, Weishi Yuan, Takashi Imai, Qimiao Si, Jianda Wu, Marton Kormos
Summary: Considerable recent progress has been made in identifying candidate materials for the transverse-field Ising chain (TFIC), a paradigmatic model for quantum criticality. In this study, we investigate the local spin dynamical structure factor of different spin components in the quantum disordered region of the TFIC. Our findings reveal surprising temperature dependencies in the low-frequency local dynamics of spins in the Ising and transverse-field directions.
Article
Physics, Multidisciplinary
Qian Wang
Summary: In this study, we systematically investigate the chaotic signatures in a quantum many-body system consisting of interacting two-level atoms and a single-mode bosonic field, known as the extended Dicke model. The presence of atomic interactions impacts the chaotic behavior of the model. By analyzing the energy spectral statistics and eigenstate structure, we reveal the quantum signatures of chaos and discuss the effect of atomic interactions. We find that the transition from integrability to chaos observed in the Dicke model is amplified when atomic interactions are introduced in the extended Dicke model.
Article
Physics, Multidisciplinary
Angel L. Corps, Rafael A. Molina, Armando Relano
Summary: This study investigates the relationship between excited state quantum phase transitions and chaos development using a modified Dicke model. It is found that the presence of quantum chaos is closely related to the existence of a quantum conserved number, which allows for the coexistence of chaos and regularity at the same energy in some cases.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Physics, Multidisciplinary
Xiang Zhang, Miriam Blaauboer
Summary: We theoretically investigate the enhancement of charging power in a Dicke quantum battery composed of N two-level systems (TLS) coupled to cavity photons. For small N, we analytically solve the time evolution of the charging process and find that the eigenvectors of the driving Hamiltonian are pseudo-Hermite polynomials, showing harmonic oscillator-like behavior. We demonstrate that the average charging power using a collective protocol is approximately root N times larger than that of the parallel protocol, and this quantum advantage is due to the coherent cooperative interactions among the TLSs rather than entanglement. Our results provide quantitative insight into the dynamic charging process of a Dicke battery and can be observed in realistic experimental conditions.
FRONTIERS IN PHYSICS
(2023)
Article
Physics, Particles & Fields
M. Dehghani
Summary: It has been shown that the exact solutions of the 4D Brans-Dicke-Maxwell (BDM) theory are Reissner-Nordstrom (RN) black holes coupled to a constant scalar field or zero. However, when the scalar potential is not constant or zero, novel black hole solutions affected by a nontrivial scalar hair are obtained. The inclusion of the scalar hair makes the asymptotic behavior of the solutions non-flat and non-AdS, and the theory allows for the occurrence of multi-horizon black holes due to the conformal invariance of Maxwell's electrodynamics, implying anti-evaporation quantum effect. The thermodynamic properties and stability of the BDM black holes are analyzed and found to satisfy the first law of black hole thermodynamics.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Multidisciplinary
Wen Liu, Liwei Duan
Summary: We investigate a generalized Dicke model with two interacting spin ensembles and a single-mode bosonic field. The phase diagram is enriched by interactions between the spin ensembles, including ferromagnetic, antiferromagnetic and paramagnetic phases. Ferromagnetic spin-spin interaction reduces the required spin-boson coupling strength for observing the superradiant phase, while antiferromagnetic interaction suppresses it. Higher-order quantum effects reveal energy gap closure, entanglement entropy divergence, and quantum fluctuation near the critical point, further confirming the quantum phase transition and providing insights into critical behaviors.
Article
Materials Science, Multidisciplinary
Lucas Squillante, Luciano S. Ricco, Aniekan Magnus Ukpong, Roberto E. Lagos-Monaco, Antonio C. Seridonio, Mariano de Souza
Summary: This article proposes a quantum analog to the Gruneisen ratio Gamma, which computes entanglement as a function of a tuning parameter lambda and investigates quantum critical points. The authors demonstrate that quantum phase transitions only occur when the ground-state energy depends nonlinearly on lambda. Furthermore, the breakdown of the Hellmann-Feynman theorem at any quantum critical point is shown.
Article
Physics, Multidisciplinary
R. Lopez-Pena, S. Cordero, E. Nahmad-Achar, O. Castanos
Summary: This paper presents a method for storing and manipulating quantum information using rotations on the Hamiltonian. The rotations can decouple the atomic levels from the electromagnetic field under certain conditions, enabling information exchange between qubits.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2023)
Article
Physics, Multidisciplinary
Jihan Hu, Shaolong Wan
Summary: In this study, it is numerically demonstrated that zero temperature OTOC can be used to detect quantum phase transition in the anisotropic Dicke model. The phase diagram is provided based on OTOC, with further investigation on finite-size and temperature effects.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
L. F. Quezada, Guo-Qing Zhang, A. Martin-Ruiz, Shi-Hai Dong
Summary: In this study, a deformed version of the Heisenberg-Weyl algebra is used to incorporate a Kerr medium and nonlinear interaction in the Dicke Model. The results show that the Kerr medium introduces a delay in reaching the super-radiant region, with the delay becoming more pronounced as the nonlinear parameter increases. One particular deformed coherent state outperforms other trial states in approximating the ground state of the system.
RESULTS IN PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Diego Gonzalez, Daniel Gutierrez-Ruiz, J. David Vergara
Summary: In this study, the researchers investigated the classical analog of the quantum metric tensor and its scalar curvature for two well-known quantum physics models. They found that in the thermodynamic limit, the classical and quantum metrics have similar behaviors near the quantum phase transition, but the scalar curvatures show divergence only under certain conditions. Additionally, numerical analysis for finite sizes revealed precursors of the quantum phase transition in metric and scalar curvature, providing insight into their characterization as functions of parameters and system size.
Article
Physics, Multidisciplinary
David Villasenor, Saul Pilatowsky-Cameo, Miguel A. Bastarrachea-Magnani, Sergio Lerma-Hernandez, Lea F. Santos, Jorge G. Hirsch
Summary: We analyze the relationship between chaos and thermalization onset in the spin-boson Dicke model. The eigenstate expectation values and distributions of off-diagonal elements validate the eigenstate thermalization hypothesis (ETH) in the chaotic region, indicating thermalization. The chaotic structure of the eigenstates is confirmed using von Neumann entanglement entropy and Shannon entropy.
Article
Physics, Multidisciplinary
Christoph P. Grams, Daniel Bruening, Severin Kopatz, Thomas Lorenz, Petra Becker, Ladislav Bohaty, Joachim Hemberger
Summary: This paper presents experimental evidence for the existence of chiral solitons in the S = 1/2 spin chain compound LiCuVO4, suggesting the presence of a quantum spin liquid state.
COMMUNICATIONS PHYSICS
(2022)
Article
Physics, Multidisciplinary
Zheng-An Wang, Yi Peng, Dapeng Yu, Heng Fan
Summary: The metrology scheme reported involves measuring the magnetic susceptibility of an atomic spin ensemble in the x and z directions, producing parameter estimation that exceeds the standard quantum limit. The scheme is robust against measurement fluctuation caused by environmental noise and defects, providing precise estimation of phi based on the number of atomic spins.
Article
Physics, Multidisciplinary
Shou-Kuan Zhao, Zi-Yong Ge, Zhong-Cheng Xiang, Guang-Ming Xue, Hai-Sheng Yan, Zi-Ting Wang, Zhan Wang, Hui-Kai Xu, Fei-Fan Su, Zhao-Hua Yang, He Zhang, Yu-Ran Zhang, Xue-Yi Guo, Kai Xu, Ye Tian, Hai-Feng Yu, Dong-Ning Zheng, Heng Fan, Shi-Ping Zhao
Summary: The Loschmidt echo is a useful diagnostic tool for evaluating the perfection of quantum time-reversal processes and the sensitivity of quantum evolution to small perturbations. In this study, we measured the Loschmidt echo in a superconducting 10-qubit system using Floquet engineering and discussed the imperfection of initial Bell-state recovery caused by the next-nearest-neighbor (NNN) coupling in the qubit device. Our results demonstrate that the Loschmidt echo is highly sensitive to small perturbations during quantum-state evolution, which can be employed to investigate aspects such as many-body decoherence and entanglement in multiqubit systems.
Article
Physics, Multidisciplinary
Qingling Zhu, Zheng-Hang Sun, Ming Gong, Fusheng Chen, Yu-Ran Zhang, Yulin Wu, Yangsen Ye, Chen Zha, Shaowei Li, Shaojun Guo, Haoran Qian, He-Liang Huang, Jiale Yu, Hui Deng, Hao Rong, Jin Lin, Yu Xu, Lihua Sun, Cheng Guo, Na Li, Futian Liang, Cheng-Zhi Peng, Heng Fan, Xiaobo Zhu, Jian-Wei Pan
Summary: Understanding phenomena in nonequilibrium dynamics of closed quantum many-body systems is crucial. This study uses a ladder-type superconducting quantum processor to simulate different models and reveals quantum thermalization and information scrambling. The controllable qubit ladder shows ergodicity and scrambling.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Kai Xu, Yu-Ran Zhang, Zheng-Hang Sun, Hekang Li, Pengtao Song, Zhongcheng Xiang, Kaixuan Huang, Hao Li, Yun-Hao Shi, Chi-Tong Chen, Xiaohui Song, Dongning Zheng, Franco Nori, H. Wang, Heng Fan
Summary: Multipartite entangled states are important resources for quantum information processing and quantum metrology. Non-Gaussian entangled states are predicted to achieve higher precision measurements than Gaussian states. In this study, a 19-qubit superconducting processor was used to characterize multiparticle entangled states generated during nonlinear dynamics. The linear Ramsey squeezing parameter (RSP) and nonlinear squeezing parameter (NLSP) were measured, and a large metrological gain over the standard quantum limit was observed, indicating a high level of multiparticle entanglement for quantum-enhanced phase sensitivity. The superconducting processor provides an ideal platform for engineering and benchmarking non-Gaussian entangled states.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Ming-Liang Hu, Jia-Ru Wang, Heng Fan
Summary: This study investigates how many observers can share the nonlocal advantage of quantum coherence in a (d x d)-dimensional state. The results show that, in a given scenario, at most one observer can demonstrate this nonlocal advantage with Bob.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Review
Physics, Multidisciplinary
Kai Xu, Heng Fan
Summary: This article reviews the research progress on noisy multiqubit quantum computation and quantum simulation, focusing on multiqubit state generations, quantum computational advantage, and simulating physics of quantum many-body systems. The perspectives of near term noisy intermediate-quantum processors are also discussed.
Article
Chemistry, Physical
Kaixuan Huang, Xiaoxia Cai, Hao Li, Zi-Yong Ge, Ruijuan Hou, Hekang Li, Tong Liu, Yunhao Shi, Chitong Chen, Dongning Zheng, Kai Xu, Zhi-Bo Liu, Zhendong Li, Heng Fan, Wei-Hai Fang
Summary: Simulating the response properties of molecules is essential for materials design, but it is a challenging task for classical computers. In this study, a practical variational quantum response (VQR) algorithm is introduced to simulate response properties without the need for deep quantum circuits. By using this algorithm on a superconducting quantum processor, the first simulation of linear response properties of molecules, including dynamic polarizabilities and absorption spectra, is reported. The results suggest that near-term quantum hardware can achieve important dynamical properties with suitable error mitigation techniques.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Physics, Multidisciplinary
Chi-Tong Chen, Yun-Hao Shi, Zhongcheng Xiang, Zheng-An Wang, Tian-Ming Li, Hao-Yu Sun, Tian-Shen He, Xiaohui Song, Shiping Zhao, Dongning Zheng, Kai Xu, Heng Fan
Summary: In this study, we present an online public quantum computation platform called ScQ, which utilizes a 1D array of a 10-qubit superconducting processor. The platform allows for single-qubit rotations and controlled-NOT gates between neighboring qubits. We demonstrate the online preparation and verification of Greenberger-Horne-Zeilinger states of up to 10 qubits using ScQ, and provide details on the graphical user interface and quantum assembly language methods. We also present the performance of the quantum computation platform, including the fidelities of logic gates and superconducting device details.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Editorial Material
Physics, Multidisciplinary
Ming-Liang Hu, Heng Fan
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Multidisciplinary Sciences
Tong Liu, Shang Liu, Hekang Li, Hao Li, Kaixuan Huang, Zhongcheng Xiang, Xiaohui Song, Kai Xu, Dongning Zheng, Heng Fan
Summary: The authors used a fully connected superconducting quantum processor with up to 15 qubits to confirm the interesting phenomenology of entanglement phase diagrams of Haar-measure random states, including entanglement phase transitions. Random quantum states are powerful tools in various scientific fields, and it has been theoretically predicted that entanglement transitions can occur for different partitions of multipartite random quantum states. This experimental study demonstrates entanglement transitions using negativity as the witness in a fully connected superconducting processor.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Wei-Bin Yan, Ying-Jie Zhang, Zhong-Xiao Man, Heng Fan, Yun-Jie Xia
Summary: A novel quantum-optics scheme for supervised learning is proposed based on the excellent control of single photons realized by atom-photon-chiral couplings. The single-photon rotating and phase-shift operations, which can be controlled by another single photon, are achieved by proper atom-photon-chiral couplings. Moreover, an algorithm is implemented to perform the supervised learning tasks by integrating the realized gates and adjusting the gate parameters.
ANNALEN DER PHYSIK
(2023)
Article
Physics, Multidisciplinary
Yun-Hao Shi, Yu Liu, Yu-Ran Zhang, Zhongcheng Xiang, Kaixuan Huang, Tao Liu, Yong-Yi Wang, Jia-Chi Zhang, Cheng-Lin Deng, Gui-Han Liang, Zheng-Yang Mei, Hao Li, Tian-Ming Li, Wei-Guo Ma, Hao-Tian Liu, Chi-Tong Chen, Tong Liu, Ye Tian, Xiaohui Song, Kai Xu, Dongning Zheng, Franco Nori, Heng Fan
Summary: This study develops a one-dimensional 43-qubit superconducting quantum processor called Chuang-tzu, which is used to simulate and characterize emergent topological states. The quantum processor is capable of capturing important topological features of quantum systems, providing a new method for studying quantum topological systems in the NISQ era.
PHYSICAL REVIEW LETTERS
(2023)
Article
Quantum Science & Technology
Wen Ning, Ri-Hua Zheng, Yan Xia, Kai Xu, Hekang Li, Dongning Zheng, Heng Fan, Fan Wu, Zhen-Biao Yang, Shi-Biao Zheng
Summary: This study reveals a more fundamental and universal interference behavior beyond Zitterbewegung in phase space for Dirac particles, which is confirmed by both numerical simulation and on-chip experiment. This discovery is of fundamental importance in science and holds potential applications in quantum technology.
NPJ QUANTUM INFORMATION
(2023)
Article
Optics
Li -Hang Ren, Yun-Hao Shi, Jin-Jun Chen, Heng Fan
Summary: We propose generalized state-dependent entropic uncertainty relations, obtaining the optimal lower bound by considering different measurement sequences. We apply this relation to detect entanglement, giving experimentally accessible lower bounds on both bipartite and tripartite entanglements. We demonstrate the detection of multipartite entanglement up to ten qubits using the QUAFU cloud quantum computation platform.
Article
Materials Science, Multidisciplinary
Shang-Shu Li, Rui-Zhen Huang, Heng Fan
Summary: We study the quantum thermalization and information scrambling dynamics of an experimentally realizable quantum spin model, which has homogeneous XX-type all-to-all interactions and random local potentials. By changing the disorder strength under a proper all-to-all interaction strength, we identify the transition from thermalization to localization. The scrambling dynamics in the localization phase shows different behaviors from local models, but the operator scrambling grows at almost the same rate in both phases. In the thermal phase, we show that fast scrambling can be observed without appealing to the semiclassical limit. We also briefly discuss the experimental realization of the model using superconducting qubit quantum simulators.
