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Modeling the performance and bandwidth of single-atom adiabatic quantum memories

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arXiv 2023年

作者： Nateeboon, Takla Cholsuk, Chanaprom Vogl, Tobias Suwanna, Sujin Optical and Quantum Physics Laboratory Department of Physics Faculty of Science Mahidol University Bangkok10400 Thailand Department of Computer Engineering TUM School of Computation Information and Technology Technical University of Munich Munich80333 Germany Abbe Center of Photonics Institute of Applied Physics Friedrich Schiller University Jena07745 Germany

Quantum memories are essential for quantum repeaters that will form the backbone of the future quantum internet. Such memory can capture a signal state for a controllable amount of time after which this state can be retrieved. In this work, we theoretically investigated how atomic material and engineering parameters affect the performance and bandwidth of a quantum memory. We have applied a theoretical model for quantum memory operation based on the Lindblad master equation and adiabatic quantum state manipulation. The materials’ properties and their uncertainty are evaluated to determine the performance of Raman-type quantum memories by showcasing two defects in two-dimensional hexagonal boron nitride (hBN). We have derived a scheme to calculate the signal bandwidth based on the material parameters as well as the maximum efficiency that can be realized. The bandwidth depends on four factors: the signal photon frequency, the dipole transition moments in the electronic structure, cavity volume, and the strength of the external control electric field. As our scheme is general and independent of materials, it can be applied to many other quantum materials with a suitable three-level structure. We therefore provided a promising route for designing and selecting materials for quantum memories. Our work is therefore an important step toward the realization of a large-scale quantum network. Copyright © 2023, The Authors. All rights reserved.

关键词： Bandwidth

Dipole coupling of a tunable hole double quantum dot in germanium hut wire to a microwave resonator

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arXiv 2019年

作者： Xu, Gang Li, Yan Gao, Fei Li, Hai-Ou Liu, He Wang, Ke Cao, Gang Xiao, Ming Wang, Ting Zhang, Jian-Jun Guo, Guang-Can Guo, Guo-Ping CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei Anhui230026 China CAS Center for Excellence Synergetic Innovation Center in Quantum Information and Quantum Physics University of Science and Technology of China Hefei Anhui230026 China National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing100190 China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing100190 China

Germanium (Ge) hole quantum dot system is a promising candidate for the realization of strong coupling of spin to superconducting resonators and scalable for multiple qubits coupling through resonators, benefiting from its strong and tunable spin-orbit coupling, long coherence time due to the special structure of Ge hut wire, and site-controlled large-scale hut wire positioning. We have coupled a reflection linear resonator to the hole double quantum dot (DQD) formed in a Ge hut wire. The amplitude and phase responses from the microwave resonator revealed the charge stability diagrams of the DQD which in good agreement with that obtained from transport measurements. The DQD interdot tunneling rate is determined ranging from 6.2 GHz to 8.5 GHz, which shows the tunability of hole-resonator interaction. Furthermore, we achieved a hole-resonator coupling rate up to 15 MHz, with the charge qubit decay rate γ of approximately 0.28 GHz. Meanwhile the hole spin–resonator coupling rate was estimated to be 0.5 MHz. These results suggest that holes of DQD in a Ge hut wire are dipole-coupled to microwave photons, potentially enabling tunable coherent hole spin-photon interactions in Ge with an inherent spin-orbit coupling. Copyright © 2019, The Authors. All rights reserved.

关键词： Nanocrystals

Exploring quantum weight enumerators from the n-qubit parallelized SWAP test

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arXiv 2024年

作者： Shi, Fei Guo, Kaiyi Zhang, Xiande Zhao, Qi QICI Quantum Information and Computation Initiative Department of Computer Science The University of Hong Kong Pokfulam Road Hong Kong School of Physics Peking University Beijing100871 China School of Mathematical Sciences University of Science and Technology of China Hefei230026 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China

Quantum weight enumerators play a crucial role in quantum error-correcting codes and multipartite entanglement. They can be used to investigate the existence of quantum error-correcting codes and k-uniform states. In this work, we build the connection between quantum weight enumerators and the n-qubit parallelized SWAP test. We discover that each shadow enumerator corresponds precisely to a probability in the n-qubit parallelized SWAP test, providing a computable and operational meaning for the shadow enumerators. Due to the non-negativity of probabilities, we obtain an elegant proof for the shadow inequalities. Concurrently, we can also calculate the Shor-Laflamme enumerators and the Rains unitary enumerators from the n-qubit parallelized SWAP test. For applications, we employ the n-qubit parallelized SWAP test to determine the distances of quantum error-correcting codes, and the k-uniformity of pure states. Our results indicate that quantum weight enumerators can be efficiently estimated on quantum computers, and opening a path to calculate the distances of quantum error-correcting codes. © 2024, CC BY.

关键词： Quantum entanglement

Exceptional Entanglement Phenomena: Non-Hermiticity Meeting Nonclassicality

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Physical Review Letters 2023年第26期131卷 260201-260201页

作者： Pei-Rong Han Fan Wu Xin-Jie Huang Huai-Zhi Wu Chang-Ling Zou Wei Yi Mengzhen Zhang Hekang Li Kai Xu Dongning Zheng Heng Fan Jianming Wen Zhen-Biao Yang Shi-Biao Zheng Fujian Key Laboratory of Quantum Information and Quantum Optics College of Physics and Information Engineering Fuzhou University Fuzhou Fujian 350108 China CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei 230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China Hefei National Laboratory Hefei 230088 China Pritzker School of Molecular Engineering University of Chicago Chicago Illinois 60637 USA Institute of Physics Chinese Academy of Sciences Beijing 100190 China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing 100190 China Department of Physics Kennesaw State University Marietta Georgia 30060 USA

Non-Hermitian (NH) extension of quantum-mechanical Hamiltonians represents one of the most significant advancements in physics. During the past two decades, numerous captivating NH phenomena have been revealed and demonstrated, but all of which can appear in both quantum and classical systems. This leads to the fundamental question: what NH signature presents a radical departure from classical physics? The solution of this problem is indispensable for exploring genuine NH quantum mechanics, but remains experimentally untouched so far. Here, we resolve this basic issue by unveiling distinct exceptional entanglement phenomena, exemplified by an entanglement transition, occurring at the exceptional point of NH interacting quantum systems. We illustrate and demonstrate such purely quantum-mechanical NH effects with a naturally dissipative light-matter system, engineered in a circuit quantum electrodynamics architecture. Our results lay the foundation for studies of genuinely quantum-mechanical NH physics, signified by exceptional-point-enabled entanglement behaviors.

关键词： Open quantum systems & decoherence Quantum control Quantum foundations Quantum measurements Quantum metrology Non-Hermitian systems

A New Authentication Protocol for Wireless Communication Network Based on IEEE802.16

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A New Authentication Protocol for Wireless Communication Net...

International Symposium on Parallel and Distributed Processing with Applications, ISPA

作者： Ruixue Li Zhiyi Fang Wei Cao Yumei Yin Peng Xu College of Computer Science and Technology Jilin University Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Changchun China College of Information Technology Liaodong University Dandong China Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy and Sciences Changchun China

After analyzing the specific security requirements of the wireless communication network based on IEEE802.16, a series of key issues about security methods and techniques were researched. A new authentication protocol for wireless mobile environment was proposed and designed. Then, its security was analyzed from the angle of technical realization and formal analysis to verify whether the original safety goals were achieved. Especially, formal analysis was mostly done. Finally, system testing was also carried out and the results were analyzed to verify function and performance of the new protocol.

关键词： Authentication Wireless application protocol Wireless communication Communication system security Information security Data security Safety Access protocols Clocks Synchronization

Tensor Rank and Stochastic Entanglement Catalysis for Multipartite Pure States

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Physical Review Letters 2010年第20期105卷 200501-200501页

作者： Lin Chen Eric Chitambar Runyao Duan Zhengfeng Ji Andreas Winter Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 Singapore 117542* Physics Department University of Michigan 450 Church Street Ann Arbor Michigan 48109-1040 USA Centre for Quantum Computation and Intelligent Systems (QCIS) Faculty of Engineering and Information Technology University of Technology Sydney New South Wales 2007 Australia State Key Laboratory of Intelligent Technology and Systems Tsinghua National Laboratory for Information Science and Technology Department of Computer Science and Technology Tsinghua University Beijing 100084 China Perimeter Institute for Theoretical Physics Waterloo Ontario N2L 2Y5 Canada Department of Mathematics University of Bristol Bristol BS8 1TW United Kingdom

The tensor rank (also known as generalized Schmidt rank) of multipartite pure states plays an important role in the study of entanglement classifications and transformations. We employ powerful tools from the theory of homogeneous polynomials to investigate the tensor rank of symmetric states such as the tripartite state |W3⟩=13(|100⟩+|010⟩+|001⟩) and its N-partite generalization |WN⟩. Previous tensor rank estimates are dramatically improved and we show that (i) three copies of |W3⟩ have a rank of either 15 or 16, (ii) two copies of |WN⟩ have a rank of 3N−2, and (iii) n copies of |WN⟩ have a rank of O(N). A remarkable consequence of these results is that certain multipartite transformations, impossible even probabilistically, can become possible when performed in multiple-copy bunches or when assisted by some catalyzing state. This effect is impossible for bipartite pure states.

关键词： Tensors

First order corrections to black hole thermodynamics: a simple approach enhanced

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arXiv 2023年

作者： Xiao, Yong Liu, Yue-Ying Key Laboratory of High-precision Computation Application of Quantum Field Theory of Hebei Province College of Physical Science and Technology Hebei University Baoding071002 China Hebei Research Center of the Basic Discipline for Computational Physics Baoding071002 China

The inclusion of higher derivative terms in the gravitational action brings about corrections to the original forms of black hole solutions and thermodynamics. A simple and valuable approach has emerged over two decades ago, which states that the first order corrections to black hole thermodynamics, caused by higher derivative terms, can be achieved without explicitly solving the perturbed metric. However, a direct application of this approach may potentially yield incorrect answers as it comes to AdS black holes, which poses a challenge to the valuable approach. In this paper, we identify the subtlety associated with AdS black holes is that certain higher derivative terms may alter the asymptotic structure of the spacetime. By taking this subtlety into account, we successfully enhance the original approach and resolve the mentioned problem. Furthermore, we make an interesting observation that the extremalization analysis that underlies this approach also plays a fundamental role in the perturbation theories of quantum mechanics and other disciplines. Copyright © 2023, The Authors. All rights reserved.

关键词： Perturbation techniques

Two-dimensional Weyl half-semimetal and tunable quantum anomalous Hall effect

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Physical Review B 2019年第6期100卷 064408-064408页

作者： Jing-Yang You Cong Chen Zhen Zhang Xian-Lei Sheng Shengyuan A. Yang Gang Su School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China Department of Physics Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education) Beihang University Beijing 100191 China Research Laboratory for Quantum Materials Singapore University of Technology and Design Singapore 487372 Singapore Center for Quantum Transport and Thermal Energy Science School of Physics and Technology Nanjing Normal University Nanjing 210023 China Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing 100190 China

Topological states of matter and two-dimensional (2D) magnetism are two fascinating topics attracting tremendous interest in current research. In this work, we explore their interplay in a single 2D material system by proposing a different topological quantum state of matter—the 2D Weyl half-semimetal (WHS), which features 2D Weyl points at the Fermi level belonging to a single spin channel, such that the low-energy electrons are described by fully spin polarized 2D Weyl fermions. We provide the condition to realize this state, which requires an in-plane magnetization and a preserved vertical mirror symmetry. Remarkably, we prove that the WHS state is a critical state sitting at the topological phase transition between two quantum anomalous Hall (QAH) insulator phases with opposite Chern numbers, such that a switching of the QAH states as well as the direction of chiral edge channels can be readily achieved by rotating the magnetization direction. Furthermore, we predict a concrete 2D material, monolayer PtCl3, as a candidate for realizing the 2D WHS state and the above intriguing effects. Our findings open up a new direction of research at the confluent point of topology and magnetism in two dimensions, and the revealed route towards switchable QAH phases will enable new designs of topological nanoelectronic devices.

关键词： Ferromagnetism Quantum anomalous Hall effect Symmetry protected topological states Topological phase transition Weyl fermions

Photoluminescence Properties and Mn4+ → Tm3+ Energy Transfer of La0.557li0.33tio3: Mn4+, Tm3+ for Thermometry and Nir-Led Applications

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SSRN

SSRN 2024年

作者： Fu, Nian Liu, Ni Yin, Tao Jin, Hao Liu, Zhenyang Wang, Dawei Guan, Li Wang, Fenghe Li, Xu Hebei Key Laboratory of Photo-Electricity Information and Materials College of Physics Science and Technology Hebei University Baoding071002 China Key Laboratory of High-precision Computation Application of Quantum Field Theory of Hebei Province Hebei University Baoding071002 China Hebei University China

Over the span of years, Mn4+-doped red phosphors have been utilized to meaningful optoelectronic devices due to their outstanding optical properties, and Tm3+ usually is an activator ion because of its efficient up-conversion emission, but inverse processes are rarely used. Herein, we have successful synthesized a series of novel La0.557Li0.33Ti1-xO3:xMn4+ (x = 0.1%-7%) phosphors. The photoluminescence properties have been detailed analysis. Using Mn4+-Tm3+ co-doped strategy, we successfully synthesis La0.557-yLi0.33Ti0.993O3:0.7%Mn4+, yTm3+ phosphors. upon excitation with 360 nm light, it exhibits two distinct emission peaks at 729 nm and 806 nm. The emission intensity of Tm3+ was greatly improved after Mn4+ doping, which is due to the energy transfer of Mn4+ to Tm3+. In terms of potential applications, utilizing fluorescence intensity ratio technology, La0.551Li0.33Ti0.993O3:0.7%Mn4+,0.6%Tm3+ exhibits maximum absolute and relative sensitivities of 3.25% K-1 and 3.49% K-1, thereby demonstrating its potential for application in optical thermometry. Furthermore, The NIR-LED using phosphor and 365 nm chips reveal potential applications of the La0.551Li0.33Ti0.993O3:Mn4+,Tm3+ phosphor in NIR night vision and biosensing. © 2024, The Authors. All rights reserved.

关键词： Energy transfer