Physical Review A最新文献

Effect of the readout efficiency of quantum measurement on the system entanglement 量子测量的读出效率对系统纠缠的影响

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.022214

Christian Carisch, Oded Zilberberg, Alessandro Romito

引用次数: 0

Dissipationless topological quantum computation for Majorana objects in the sparse-dense mixed encoding process 稀疏-密集混合编码过程中的马约拉纳对象无耗散拓扑量子计算

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.022609

Ye-Min Zhan, Guan-Dong Mao, Yu-Ge Chen, Yue Yu, Xi Luo

{"title":"Dissipationless topological quantum computation for Majorana objects in the sparse-dense mixed encoding process","authors":"Ye-Min Zhan, Guan-Dong Mao, Yu-Ge Chen, Yue Yu, Xi Luo","doi":"10.1103/physreva.110.022609","DOIUrl":"https://doi.org/10.1103/physreva.110.022609","url":null,"abstract":"Topological quantum computation based on Majorana objects is subject to a significant challenge because at least some of the two-qubit quantum gates rely on the fermion (either charge or spin) parity of the qubits. This dependency renders the quantum operations involving these gates probabilistic when attempting to advance quantum processes within the quantum circuit model. Such an approach leads to significant information loss whenever measurements yield the undesired fermion parity. To resolve the problem of wasting information, we devise topological operations that allow for the nondissipative correction of information from undesired fermion parity to the desired one. We will use the sparse-dense mixed encoding process for the controlled-NOT gate as an example to explain how corrections can be implemented without affecting the quantum information carried by the computational qubits. This correction process can be applied to either the undesired input qubits or the fermion parity-dependent quantum gates, and it works for both Majorana-zero-mode-based and Majorana-edge-mode-based topological quantum computation.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Twist-and-turn dynamics of spin squeezing in bosonic Josephson junctions: Enhanced shortcuts-to-adiabaticity approach 玻色约瑟夫森结中自旋挤压的扭转动力学：增强的绝热捷径方法

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.022610

Manuel Odelli, Andreas Ruschhaupt, Vladimir M. Stojanović

{"title":"Twist-and-turn dynamics of spin squeezing in bosonic Josephson junctions: Enhanced shortcuts-to-adiabaticity approach","authors":"Manuel Odelli, Andreas Ruschhaupt, Vladimir M. Stojanović","doi":"10.1103/physreva.110.022610","DOIUrl":"https://doi.org/10.1103/physreva.110.022610","url":null,"abstract":"The twist-and-turn dynamics of spin squeezing results from the interplay of the one-axis-twisting (nonlinear in the collective-spin operators) and the transverse-field turning (linear) term in the underlying Lipkin-Meshkov-Glick-type Hamiltonian, both with constant (time-independent) prefactors. Using shortcuts to adiabaticity (STA) and the recently developed enhanced version thereof (eSTA), we demonstrate here that dynamics of this type can be utilized for a fast and robust preparation of spin-squeezed states in internal bosonic Josephson junctions, i.e., condensates of cold bosonic atoms in two different internal (hyperfine) states (single-boson modes) coupled through Rabi rotations. Assuming that the initial state of this system is its ground state for a given initial value of the (time-dependent) linear coupling strength and that the nonlinear coupling strength remains constant, we set out to determine the time dependence of the linear (Rabi) coupling strength that allows for the generation of spin-squeezed states using the STA- and eSTA-based approaches. We then characterize the modified twist-and-turn dynamics of this system by evaluating the coherent spin-squeezing and number-squeezing parameters, as well as the fidelity of the target spin-squeezed states. In this way, we show that the eSTA approach allows for a particularly robust realization of strongly spin-squeezed states in this system, consistently outperforming its adiabatic and STA-based counterparts, even for systems with several hundred particles. Our method could also be employed for the generation of metrologically-useful non-Gaussian states.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spatiotemporal coupled-mode theory for Fabry-Pérot resonators and its application to linear variable filters 法布里-佩罗谐振器的时空耦合模式理论及其在线性可变滤波器中的应用

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.023511

Dmitry A. Bykov, Evgeni A. Bezus, Leonid L. Doskolovich

{"title":"Spatiotemporal coupled-mode theory for Fabry-Pérot resonators and its application to linear variable filters","authors":"Dmitry A. Bykov, Evgeni A. Bezus, Leonid L. Doskolovich","doi":"10.1103/physreva.110.023511","DOIUrl":"https://doi.org/10.1103/physreva.110.023511","url":null,"abstract":"Coupled-mode theory (CMT) is a widely used approach for describing resonances and eigenmodes in various photonic structures. Here, we propose a formulation of the CMT describing resonant multilayer structures. In particular, we revisit the conventional Fabry-Pérot resonator and describe its optical properties from the point of view of the spatiotemporal formulation of the CMT. This formulation provides partial differential equations describing both temporal and spatial evolution of the field distribution, thus generalizing the conventional temporal and spatial versions of the CMT. The developed CMT takes into account the symmetry of the considered structure, energy conservation law, reciprocity, and causality. By considering the parameters of the developed CMT to be spatially dependent, we apply it to describe the optical properties of linear variable filters (LVFs) comprising two Bragg mirrors separated by a wedge-shaped (tapered) layer. In good agreement with the results of the rigorous numerical solution of Maxwell's equations, the proposed CMT accurately reproduces the broadening of the resonant peak and the appearance of Fizeau fringes when increasing the wedge angle of the LVF.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Zeno effect suppression of gauge drift in quantum simulations 量子模拟中的芝诺效应抑制量规漂移

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.022417

Carter Ball, Thomas D. Cohen

引用次数: 0

Multiple quantum Mpemba effect: Exceptional points and oscillations 多重量子姆彭巴效应：异常点和振荡

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.022213

Amit Kumar Chatterjee, Satoshi Takada, Hisao Hayakawa

{"title":"Multiple quantum Mpemba effect: Exceptional points and oscillations","authors":"Amit Kumar Chatterjee, Satoshi Takada, Hisao Hayakawa","doi":"10.1103/physreva.110.022213","DOIUrl":"https://doi.org/10.1103/physreva.110.022213","url":null,"abstract":"We explore the role of exceptional points and complex eigenvalues on the occurrence of the quantum Mpemba effect. To this end, we study a two-level driven dissipative system subjected to an oscillatory electric field and dissipative coupling with the environment. We find that both exceptional points and complex eigenvalues can lead to <i>multiple</i> quantum Mpemba effect. It occurs in an observable when time-evolved copies corresponding to two different initial conditions, one initially having higher observable value compared to the other and both relaxing towards the same steady state, intersect each other more than once during their relaxation process. Each of the intersections denotes a quantum Mpemba effect and marks the reversal of identities between the two copies, i.e., the copy with higher observable value before the intersection becomes the lower-valued copy (and vice versa) after the intersection. Such multiple intersections originate from additional algebraic time dependence at the exceptional points and due to oscillatory relaxation in the case of complex eigenvalues. We provide analytical results for quantum Mpemba effect in the density matrix in presence of coherence. Depending on the control parameters (drive and dissipation), observables such as energy, von Neumann entropy, temperature, etc., exhibit either single or multiple quantum Mpemba effect. However, the distance from steady state measured in terms of the Kullback-Leibler divergence shows only single quantum Mpemba effect although the corresponding speed gives rise to either single or multiple quantum Mpemba effect.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Process of dissociation of NH3 by electron impact in low-temperature plasma and its isotope effect 低温等离子体中电子撞击解离 NH3 的过程及其同位素效应

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.l020803

Xianwu Jiang, Yingqi Chen, Hainan Liu, Chi-Hong Yuen, Viatcheslav Kokoouline

{"title":"Process of dissociation of NH3 by electron impact in low-temperature plasma and its isotope effect","authors":"Xianwu Jiang, Yingqi Chen, Hainan Liu, Chi-Hong Yuen, Viatcheslav Kokoouline","doi":"10.1103/physreva.110.l020803","DOIUrl":"https://doi.org/10.1103/physreva.110.l020803","url":null,"abstract":"Understanding the dissociative electron attachment (DEA) in low-temperature ammonia plasma is crucial for many technological applications, in particular, for alternative energy sources. However, theoretical modeling of this process has been challenging due to the complex interplay of electronic motion and multidimensional nuclear dynamics. This Letter presents a theoretical approach to investigate the process, applying it to the breakup of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>NH</mi><mn>3</mn></msub></math> molecule by low-energy electrons. The potential energy surface of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>NH</mi><mn>3</mn></msub><msup><mrow></mrow><mo>−</mo></msup></mrow></math> 5.5 eV resonant state is computed to elucidate the mechanism of the dissociative process. The cross section of DEA via the 5.5 eV resonance is then calculated for both <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>NH</mi><mn>3</mn></msub></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>ND</mi><mn>3</mn></msub></math>. The positions of the peaks in both cross sections and the ratio between them are in excellent agreement with previous experiments. Our findings suggest that the developed theoretical model accurately describes the DEA process and could serve as a useful tool for providing DEA cross sections for other molecules to model low-temperature plasma.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantum backflow current in a ring: Optimal bounds and fractality 环中的量子逆流：最佳边界和分形

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.022216

Arseni Goussev, Felix Quinque, Jaewoo Joo, Andrew Burbanks

{"title":"Quantum backflow current in a ring: Optimal bounds and fractality","authors":"Arseni Goussev, Felix Quinque, Jaewoo Joo, Andrew Burbanks","doi":"10.1103/physreva.110.022216","DOIUrl":"https://doi.org/10.1103/physreva.110.022216","url":null,"abstract":"The probability density of a quantum particle moving freely within a circular ring can exhibit local flow patterns inconsistent with its angular momentum, a phenomenon known as quantum backflow. In this study, we examine a quantum particle confined to a ring and prepared in a state composed of a fixed (yet arbitrary) number of lowest-energy eigenstates with nonnegative angular momentum. We investigate the time-dependent behavior of the probability current at a specified point along the ring's circumference. We establish precise lower and upper bounds for this probability current, thereby delineating the exact scope of the quantum backflow effect. We also present an analytical expression for a quantum state that yields a record-high backflow probability transfer, reaching over <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>95</mn><mo>%</mo></mrow></math> of the theoretical bound. Furthermore, our investigation yields compelling numerical and analytical evidence supporting the conjecture that the current-versus-time function associated with states maximizing backflow probability transfer forms a fractal curve with a dimension of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>7</mn><mo>/</mo><mn>4</mn></mrow></math>. The observed fractality may provide a characteristic, experimentally relevant signature of quantum backflow near the probability-transfer bound.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermodynamic analysis of algorithmic cooling protocols: Efficiency metrics and improved designs 算法冷却协议的热力学分析：效率指标和改进设计

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.022215

Junan Lin, Nayeli A. Rodríguez-Briones, Eduardo Martín-Martínez, Raymond Laflamme

{"title":"Thermodynamic analysis of algorithmic cooling protocols: Efficiency metrics and improved designs","authors":"Junan Lin, Nayeli A. Rodríguez-Briones, Eduardo Martín-Martínez, Raymond Laflamme","doi":"10.1103/physreva.110.022215","DOIUrl":"https://doi.org/10.1103/physreva.110.022215","url":null,"abstract":"Algorithmic cooling (AC) protocols have been predominantly studied for their cooling capabilities, with limited attention paid to their thermodynamic properties. This work explores an alternative perspective by analyzing a broad family of AC protocols from a thermodynamic standpoint. First, we give an in-depth review and formal classification of standard AC protocols. Leveraging the transfer matrix formalism, we achieve a consistent calculation of performance metrics, encompassing both cooling limits and target state evolution. We obtained a unification of these diverse cooling limits into a single, coherent mathematical expression, streamlining comparative analyses. Then, to assess the efficiency of coherent cooling protocols, we introduce two generic metrics: the coefficient of performance <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>K</mi></math> and Landauer's Ratio <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>R</mi><mi>L</mi></msub></math>, and establish a direct interrelation. Applying these metrics, we thoroughly evaluate selected AC protocols, highlighting their relative strengths. Finally, we propose improved versions of AC protocols that exhibit enhanced thermodynamic performance, achieving desired target temperatures with lower work inputs. This research contributes to a deeper understanding of AC protocols and provides valuable insights for designing efficient cooling strategies in various applications.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Interaction time of Schrödinger cat states with a periodically driven quantum system: Symplectic covariance approach 薛定谔猫态与周期驱动量子系统的相互作用时间：交映协方差方法

IF 2.9 2区物理与天体物理

Physical Review A Pub Date : 2024-08-12 DOI: 10.1103/physreva.110.022416

D. Woźniak, B. J. Spisak, M. Kalka, M. Wołoszyn, M. Wleklińska, P. Pigoń, D. Kołaczek

引用次数: 0