检索结果-内蒙古大学图书馆

Electrically driven motion, destruction, and chirality change of polar vortices in oxide superlattices

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2022年第3期65卷 77-84页

作者： Pan Chen Congbing Tan Zhexin Jiang Peng Gao Yuanwei Sun Lifen Wang Xiaomei Li Ruixue Zhu Lei Liao Xu Hou Ke Qu Ning Li Xiaomin Li Zhi Xu Kaihui Liu Wenlong Wang Jinbin Wang Xiaoping Ouyang Xiangli Zhong Jie Wang Xuedong Bai Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China International Center for Quantum Materials Electron Microscopy LaboratorySchool of PhysicsPeking UniversityBeijing 100871China Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials School of Physics and ElectronicsHunan University of Science and TechnologyXiangtan 411201China Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China Collaborative Innovation Center of Quantum Matter Beijing 100871China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China State Key Laboratory for Artificial Microstructure&Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang UniversityHangzhou 310027China

Topological polar vortices, which are electric analogs of magnetic objects, present great potential in applications of future nanoelectronics because of their nanometer size, anomalous dielectric response, and chirality. To enable the functionalities, it is prerequisite to manipulate the polar states and chirality by using external stimuli. Here, we probe the evolutions of polar state and chirality evolutions of topological polar vortices in Pb TiO;/Sr TiO;superlattices under an electric field by using atomically resolved in situ scanning transmission electron microscopy and phase-field simulations. We find that, under electric field, the chiral vortex cores can be moved laterally to form close-pair structures, transform into a/c domain stripes, and finally become a nonchiral c-domain. Such transition is reversible and spontaneous after bias removal. Interestingly, during switching and backswitching events, the vortex rotation can be changed, offering a potential strategy to manipulate vortex chirality. The revealed dynamic behavior of individual polar vortices at the atomic scale provides fundamentals for future device applications.

关键词： chirality polar vortex ferroelectrics in situ transmission electron microscopy phase-field simulations

Anti-parity-time symmetry hidden in a damping linear resonator

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Xu, Xun-Wei Liao, Jie-Qiao Jing, Hui Kuang, Le-Man Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan Province Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China

Phase transition from the over-damping to under-damping states is a ubiquitous phenomenon in physical systems. However, what kind of symmetry is broken associated with this phase transition remains unclear. Here, we discover that this phase transition is determined by an anti-parity-time (anti-PT ) symmetry hidden in a single damping linear resonator, which is significantly different from the conventional anti-PT -symmetric systems with two or more modes. We show that the breaking of the anti-PT symmetry yields the phase transition from the over-damping to under-damping states, with an exceptional point (EP) corresponding to the critical-damping state. Moreover, we propose an optomechanical scheme to show this anti-PT symmetry breaking by using the optical spring effect in a quadratic optomechanical system. We also suggest an optomechanical sensor with the sensitivity enhanced significantly around the EPs for the anti-PT symmetry breaking. Our work unveils the anti-PT symmetry hidden in damping oscillations and hence opens up new possibilities for exploiting wide anti-PT symmetry applications in single damping linear resonators. Copyright © 2022, The Authors. All rights reserved.

关键词： Damping

Multiterminal Nonreciprocal Routing in an Optomechanical Plaquette via Synthetic Magnetism

学校读者我要写书评

暂无评论

arXiv 2023年

Optomechanical systems with parametric coupling between optical (photon) and mechanical (phonon) modes provide a useful platform to realize various magnetic-free nonreciprocal devices, such as isolators, circulators, and directional amplifiers. However, nonreciprocal router with multiaccess channels has not been extensively studied yet. Here, we propose a nonreciprocal router with one transmitter, one receiver, and two output terminals, based on an optomechanical plaquette composing of two optical modes and two mechanical modes. The time-reversal symmetry of the system is broken via synthetic magnetism induced by driving the two optical modes with phase-correlated laser fields. The prerequisites for nonreciprocal routing are obtained both analytically and numerically, and the robustness of the nonreciprocity is demonstrated numerically. Multiterminal nonreciprocal router in optomechanical plaquette provides a useful quantum node for development of quantum network information security and realization of quantum secure communication. Copyright © 2023, The Authors. All rights reserved.

关键词： Quantum cryptography

Quantum simulation of a three-mode optomechanical system based on the Fredkin-type interaction

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Liu, Jin Zhou, Yue-Hui Huang, Jian Huang, Jin-Feng Liao, Jie-Qiao Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan Province Department of Physics Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China

The realization of multimode optomechanical interactions in the single-photon strong-coupling regime is a desired task in cavity optomechanics, but it remains a big challenge in realistic physical systems. In this work we propose a reliable scheme to simulate a three-mode optomechanical system working in the single-photon strongcoupling regime based on the Fredkin-type interaction. This is achieved by utilizing two strong drivings to the two exchange-coupled modes in the Fredkin-type coupling involving one optical mode and two mechanical-like modes. As an application of this enhanced three-mode nonlinear optomechanical coupling, we show how to generate entangled cat states of the mechanical-like modes using the conditional displacement mechanism. The quantum coherence effects in the generated states are investigated by calculating the two-mode joint Wigner function and quantum entanglement. The influence of the system dissipation on the state generation is also considered. This work will open up a different route to the study of multimode optomechanical interactions at the single-photon level. Copyright © 2020, The Authors. All rights reserved.

关键词： Particle beams

Network nonlocality sharing via weak measurements in the extended bilocal scenario

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Hou, Wenlin Liu, Xiaowei Ren, Changliang Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan Province Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China

Quantum network correlations have attracted strong interest as the emergency of the new types of violations of locality. Here we investigated network nonlocal sharing in the extended bilocal scenario via weak measurements. Interestingly, network nonlocal sharing can be revealed from the multiple violation of BRGP inequalities of any Alicen − Bob − Charliem, which has no counterpart in the case of Bell nonlocal sharing scenario. Such discrepancy may imply an intrinsic difference between network nonlocality and Bell nonlocality. Passive and active network nonlocal sharing as two distinct types of nonlocality sharing have been completely analyzed. In addition, noise resistance of network nonlocal sharing were also discussed. Copyright © 2021, The Authors. All rights reserved.

关键词： Bells

Strong decays of doubly charmed and bottom baryons

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Shu, Ya-Li Song, Qing-Fu Lü, Qi-Fang Department of Physics Hunan Normal University Changsha410081 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Changsha410081 China Key Laboratory for Matter Microstructure and Function of Hunan Province Changsha410081 China

In this work, we have investigated the strong decays for low-lying excited states of doubly charmed and bottom baryons in the constituent quark model. Our results indicate that some λ−mode Ξcc/bb(1P) and Ωcc/bb(1P) states are relatively narrow, which are very likely to be discovered by future experiments. The light meson emissions for the low-lying ρ−mode states are highly suppressed due to the orthogonality of wave functions between initial and final states. Moreover, the strong decay behaviors for doubly charmed and bottom baryons preserve the heavy superflavor symmetry well, where the small violation originates from the finite heavy quark masses and different phase spaces. We hope that present theoretical results for undiscovered doubly charmed and bottom baryons can provide helpful information for future experiments and help us better understand the heavy quark symmetry. Copyright © 2024, The Authors. All rights reserved.

关键词： Excited states

Quantum simulation of tunable and ultrastrong mixed-optomechanics

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Zhou, Yue-Hui Yin, Xian-Li Liao, Jie-Qiao Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan Province Department of Physics Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China

We propose a reliable scheme to simulate tunable and ultrastrong mixed (first-order and quadratic optomechanical couplings coexisting) optomechanical interactions in a coupled two-mode bosonic system, in which the two modes are coupled by a cross-Kerr interaction and one of the two modes is driven through both the single- and two-excitation processes. We show that the mixed-optomechanical interactions can enter the single-photon strong-coupling and even ultrastrong-coupling regimes. The strengths of both the first-order and quadratic optomechanical couplings can be controlled on demand, and hence first-order, quadratic, and mixed optomechanical models can be realized. In particular, the thermal noise of the driven mode can be suppressed totally by introducing a proper squeezed vacuum bath. We also study how to generate the superposition of coherent squeezed state and vacuum state based on the simulated interactions. The quantum coherence effect in the generated states is characterized by calculating the Wigner function in both the closed- and open-system cases. This work will pave the way to the observation and application of ultrastrong optomechanical effects in quantum simulators. Copyright © 2021, The Authors. All rights reserved.

关键词： Couplings

Two-photon scattering in mixed cavity optomechanics

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Chen, Dong-Cheng Zhou, Yue-Hui Huang, Jin-Feng Liao, Jie-Qiao Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan Province Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China

We study two-photon scattering in a mixed cavity optomechanical system, which is composed of a singlemode cavity field coupled to a single-mode mechanical oscillation via both the first-order and quadratic optomechanical interactions. By solving the scattering problem within theWigner-Weisskopf framework, we obtain the analytical scattering state and find four physical processes associated with the two-photon scattering in this system. We calculate the two-photon scattering spectrum and find that two-photon frequency anticorrelation can be induced in the scattering process. We also establish the relationship between the parameters of the mixed cavity optomechanical system and the characteristics of the two-photon scattering spectrum. This work not only provides a scattering means to create correlated photon pairs, but also presents a spectrometric method to characterize the optomechanical systems. Copyright © 2021, The Authors. All rights reserved.

关键词： Photons

Accelerated ground-state cooling of an optomechanical resonator via shortcuts to adiabaticity

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Liu, Yu-Hong Yin, Xian-Li Huang, Jin-Feng Liao, Jie-Qiao Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan Province Department of Physics Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China

Ground-state cooling of mechanical resonators is an important task in quantum optomechanics, because it is a necessary prerequisite for creation, manipulation, and application of macroscopic mechanical coherence. Here, we propose a transient-state scheme to accelerate ground-state cooling of a mechanical resonator in a three-mode loop-coupled optomechanical system via shortcuts to adiabaticity (STA). We consider four kinds of coupling protocols and calculate the evolution of the mean phonon number of the mechanical resonator in both the adiabatic and STA cases. We verify that the ground-state cooling of the mechanical resonator can be achieved with the STA method in a much shorter period. The STA method can also be generalized to accelerate other adiabatic processes in cavity optomechanics, and hence this work will open up a new realm of fast optomechanical manipulations. © 2021, CC BY.

关键词： Ground state