Physical Review A最新文献

{"title":"Creating dynamic leakage-free paths using coarse-graining techniques in the presence of decoherence","authors":"S. L. Wu, W. Ma, Lian-Ao Wu","doi":"10.1103/physreva.110.032212","DOIUrl":"https://doi.org/10.1103/physreva.110.032212","url":null,"abstract":"We present a method aimed at protecting unitary dynamics in the presence of decoherence, by integrating leakage elimination operators (LEOs) into the system's evolution to create dynamical leakage-free paths. Deriving the dynamical equation for an open quantum system with general drives can be challenging. Our approach avoids the rotating wave approximation and instead uses the coarse-grained averaging technique to derive a quantum master equation for such systems. The combination of the coarse-graining approach and LEO operators appears suitable to study Markovian control methods. We show that employing LEO pulses in specific subspaces can reduce errors arising from undesired transitions due to decoherence. Notably, satisfactory final fidelity can still be achieved even when the reservoir is at a finite temperature. By looking into the dynamical equation governing the quantum state on the dynamical leakage-free path, we provide analytical insights into the effectiveness of the LEO method in suppressing decoherence effects.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"30 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205851","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}

{"title":"Robust two-qubit gate with reinforcement learning and dropout","authors":"Tian-Niu Xu, Yongcheng Ding, José D. Martín-Guerrero, Xi Chen","doi":"10.1103/physreva.110.032614","DOIUrl":"https://doi.org/10.1103/physreva.110.032614","url":null,"abstract":"In the realm of quantum control, reinforcement learning, a prominent branch of machine learning, emerges as a competitive candidate for computer-assisted optimal experiment design. This paper investigates the extent to which guidance from human experts is necessary for effectively implementing reinforcement learning in the design of quantum control protocols. Specifically, our focus lies on engineering a robust two-qubit gate, utilizing a combination of analytical solutions as prior knowledge and techniques from computer science. Through thorough benchmarking of various models, we identify dropout—a widely used method for mitigating overfitting in machine learning—as a particularly robust approach. Our findings demonstrate the potential of integrating computer science concepts to propel the development of advanced quantum technologies.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"102 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262619","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}

{"title":"Long-lived coherences in strongly interacting spin ensembles","authors":"William K. Schenken, Simon A. Meynell, Francisco Machado, Bingtian Ye, Claire A. McLellan, Maxime Joos, V. V. Dobrovitski, Norman Y. Yao, Ania C. Bleszynski Jayich","doi":"10.1103/physreva.110.032612","DOIUrl":"https://doi.org/10.1103/physreva.110.032612","url":null,"abstract":"Periodic driving has emerged as a powerful tool to control, engineer, and characterize many-body quantum systems. However, the required pulse sequences are often complex, long, or require the ability to control the individual degrees of freedom. In this work, we study how a simple Carr-Purcell–Meiboom-Gill (CPMG)-like pulse sequence can be leveraged to enhance the coherence of a large ensemble of spin qubits and serve as an important characterization tool. We implement the periodic drive on an ensemble of dense nitrogen-vacancy (NV) centers in diamond and examine the effect of pulse rotation offset as a control parameter on the dynamics. We use a single diamond sample prepared with several spots of varying NV density, which, in turn, varies the NV-NV dipolar interaction strength. Counterintuitively, we find that rotation offsets deviating from the ideal <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>π</mi></math> pulse in the CPMG sequence (often classified as pulse errors) play a critical role in preserving coherence along an axis set by the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>π</mi></math> pulses even at nominally zero rotation offset. The cause of the coherence preservation is an emergent effective field that scales linearly with the magnitude of the rotation offset for small offsets. In addition to extending coherence, we compare the rotation offset dependence of coherence to numerical simulations to measure the disorder and dipolar contributions to the Hamiltonian to quantitatively extract the densities of the constituent spin species within the diamond.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"404 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205850","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}

{"title":"Quantum resource theory of coding for error correction","authors":"Dong-Sheng Wang, Yuan-Dong Liu, Yun-Jiang Wang, Shunlong Luo","doi":"10.1103/physreva.110.032413","DOIUrl":"https://doi.org/10.1103/physreva.110.032413","url":null,"abstract":"Error-correction codes are central for fault-tolerant information processing. Here we develop a rigorous framework to describe various coding models based on quantum resource theory of superchannels. We find, by treating codings as superchannels, a hierarchy of coding models can be established, including the entanglement assisted or unassisted settings, and their local versions. We show that these coding models can be used to classify error-correction codes and accommodate different computation and communication settings depending on the data type, side channels, and pre-/postprocessing. We believe the coding hierarchy could also inspire new coding models and error-correction methods.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"7 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205857","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}

{"title":"Ytterbium atom interferometry for dark matter searches","authors":"Yifan Zhou, Rowan Ranson, Michalis Panagiotou, Chris Overstreet","doi":"10.1103/physreva.110.033313","DOIUrl":"https://doi.org/10.1103/physreva.110.033313","url":null,"abstract":"We analyze the projected sensitivity of a laboratory-scale ytterbium atom interferometer to scalar, vector, and pseudoscalar dark matter signals. A frequency ratio measurement between two transitions in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi>Yb</mi><mprescripts></mprescripts><none></none><mn>171</mn></mmultiscripts></math> enables a search for variations of the fine-structure constant that could surpass existing limits by a factor of 100 in the mass range <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mn>10</mn><mrow><mo>−</mo><mn>22</mn></mrow></msup></math>–<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mn>10</mn><mrow><mo>−</mo><mn>16</mn></mrow></msup></math> eV. Differential accelerometry between ytterbium isotopes yields projected sensitivities to scalar and vector dark matter couplings that are stronger than the limits set by the MICROSCOPE equivalence principle test, and an analogous measurement in the MAGIS-100 long-baseline interferometer would be more sensitive than previous bounds by factors of 10 or more. A search for anomalous spin torque in MAGIS-100 is projected to reach similar sensitivity to atomic magnetometry experiments. We discuss strategies for mitigating the main systematic effects in each measurement. These results indicate that improved dark matter searches with ytterbium atom interferometry are technically feasible.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"99 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205855","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}

{"title":"Quantum battery with interactive atomic collective charging","authors":"Dayang Zhang, Shuangquan Ma, Yunxiu Jiang, Youbin Yu, Guangri Jin, Aixi Chen","doi":"10.1103/physreva.110.032211","DOIUrl":"https://doi.org/10.1103/physreva.110.032211","url":null,"abstract":"The collective charge of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math> two-level atoms interacting in an open system is investigated. In contrast to a no atomic dissipation quantum battery, the battery remains at a steady state after reaching the moment of full charge. Considering the interactions between atoms, we find that the energy storage of quantum batteries will be significantly enhanced with the increase of atomic repulsion, and the attraction between atoms will exacerbate the dissipation of batteries in the environment. We extend this conclusion to two-level batteries in the drive field and three-level atom quantum batteries. In addition, we also investigate the dissipative charging process of multiatom quantum batteries and find that the number of atoms during the charging process can to some extent affect the energy conversion efficiency during the charging process. Under extreme conditions, the inverse temperature <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>β</mi></math> can disrupt the energy storage of the battery.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"10 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205858","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}

{"title":"Future-input-dependent model for Greenberger-Horne-Zeilinger correlations","authors":"Izhar Neder, Nathan Argaman","doi":"10.1103/physreva.110.032209","DOIUrl":"https://doi.org/10.1103/physreva.110.032209","url":null,"abstract":"It is widely appreciated, due to Bell's theorem, that quantum phenomena are inconsistent with local-realist models. In this context, locality refers to local causality, and there is thus an open possibility for reproducing the quantum predictions with models which internally violate the causal arrow of time, while otherwise adhering to the relevant locality condition. So far, this possibility has been demonstrated only at a toy-model level, and only for systems involving one or two spins (or photons). The present work extends one of these models to quantum correlations between three or more spins which are entangled in the Greenberger-Horne-Zeilinger state.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"45 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205859","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}

{"title":"Bipartite representations and many-body entanglement of pure states of N indistinguishable particles","authors":"J. A. Cianciulli, R. Rossignoli, M. Di Tullio, N. Gigena, Federico Petrovich","doi":"10.1103/physreva.110.032414","DOIUrl":"https://doi.org/10.1103/physreva.110.032414","url":null,"abstract":"We analyze a general bipartite-like representation of arbitrary pure states of <i>N</i> indistinguishable partcles, valid for both bosons and fermions, based on <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>M</mi></math>- and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><mi>N</mi><mo>−</mo><mi>M</mi><mo>)</mo></mrow></math>-particle states. It leads to exact <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><mi>M</mi><mo>,</mo><mi>N</mi><mo>−</mo><mi>M</mi><mo>)</mo></mrow></math> Schmidt-like expansions of the state for any <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>M</mi><mo>&lt;</mo><mi>N</mi></mrow></math> and is directly related to the isospectral reduced <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>M</mi></math>- and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><mi>N</mi><mo>−</mo><mi>M</mi><mo>)</mo></mrow></math>-body density matrices <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>ρ</mi><mrow><mo>(</mo><mi>M</mi><mo>)</mo></mrow></msup></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>ρ</mi><mrow><mo>(</mo><mi>N</mi><mo>−</mo><mi>M</mi><mo>)</mo></mrow></msup></math>. The formalism also allows for reduced yet still exact Schmidt-like decompositions associated with blocks of these densities, in systems having a fixed fraction of the particles in some single-particle subspace. Monotonicity of the ensuing <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>M</mi></math>-body entanglement under a certain set of quantum operations is also discussed. Illustrative examples in fermionic and bosonic systems with pairing correlations are provided, which show that in the presence of dominant eigenvalues in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>ρ</mi><mrow><mo>(</mo><mi>M</mi><mo>)</mo></mrow></msup></math>, approximations based on a few terms of the pertinent Schmidt expansion can provide a reliable description of the state. The associated one- and two-body entanglement spectrum and entropies are also analyzed.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"6 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205862","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}

{"title":"Quantum sensing of ultralow temperature in biwire ultracold polar molecules","authors":"Abdelâali Boudjemâa, Karima Abbas, Asma Tahar Taiba, Qing-Shou Tan","doi":"10.1103/physreva.110.032611","DOIUrl":"https://doi.org/10.1103/physreva.110.032611","url":null,"abstract":"We present a systematic study of quantum sensing of ultralow temperature in biwire ultracold polar molecules of a quasi-one-dimensional (1D) trap by exploring the dynamics of two physically different qubit models. The two models consist of a trapped impurity atom that act as a temperature quantum sensor interacting with polar molecules reservoir, where dipole moments are aligned head-to-tail across the wires. Our model takes advantage of the adjustable interwire distance to accurately control the precision ultralow temperatures measurement. We show that the system undergoes a transition from Markovian to non-Markovian dynamics, which can be controlled by changing the interwire separation, the dipole-–dipole interaction (DDI), and the temperature. We characterize the thermometric performance using the quantum signal-to-noise ratio for both models and demonstrate that such a quantity exhibits a higher peak at ultralow temperature. We therefore emphasize that ultracold polar molecules are crucial for revolutionizing temperature sensing.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"1 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205861","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}

{"title":"Robust estimation of nonlinear properties of quantum processes","authors":"Yuqing Wang, Guoding Liu, Zhenhuan Liu, Yifan Tang, Xiongfeng Ma, Hao Dai","doi":"10.1103/physreva.110.032415","DOIUrl":"https://doi.org/10.1103/physreva.110.032415","url":null,"abstract":"The accurate and robust estimation of quantum process properties is crucial for quantum information processing and many-body physics. Combining classical shadow tomography and randomized benchmarking, Helsen <i>et al.</i> introduced a method to estimate the linear properties of quantum processes. In this work, we focus on the estimation protocols of nonlinear process properties that are robust to state preparation and measurement errors. We introduce two protocols, both utilizing random gate sequences but employing different postprocessing methods, which make them suitable for measuring different nonlinear properties. The first protocol offers a robust and sound method to estimate the out-of-time-ordered correlation, as demonstrated numerically in an Ising model. The second protocol estimates unitarity, effectively characterizing the incoherence of quantum channels. We expect the two protocols to be useful tools for exploring quantum many-body physics and characterizing quantum processes.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"147 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205860","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}