PRX quantum : a Physical Review journal最新文献_第10页

Quantum Error Correction with Metastable States of Trapped Ions Using Erasure Conversion 用擦除转换对俘获离子亚稳态量子误差的校正

PRX quantum : a Physical Review journal Pub Date : 2022-10-26 DOI: 10.1103/PRXQuantum.4.020358

Mingyu Kang, W. C. Campbell, K. Brown

引用次数: 12

Classical Simulation of Short-Time Quantum Dynamics 短时量子动力学的经典模拟

PRX quantum : a Physical Review journal Pub Date : 2022-10-20 DOI: 10.1103/PRXQuantum.4.020340

D. Wild, Álvaro M. Alhambra

{"title":"Classical Simulation of Short-Time Quantum Dynamics","authors":"D. Wild, Álvaro M. Alhambra","doi":"10.1103/PRXQuantum.4.020340","DOIUrl":"https://doi.org/10.1103/PRXQuantum.4.020340","url":null,"abstract":"Recent progress in the development of quantum technologies has enabled the direct investigation of dynamics of increasingly complex quantum many-body systems. This motivates the study of the complexity of classical algorithms for this problem in order to benchmark quantum simulators and to delineate the regime of quantum advantage. Here we present classical algorithms for approximating the dynamics of local observables and nonlocal quantities such as the Loschmidt echo, where the evolution is governed by a local Hamiltonian. For short times, their computational cost scales polynomially with the system size and the inverse of the approximation error. In the case of local observables, the proposed algorithm has a better dependence on the approximation error than algorithms based on the Lieb-Robinson bound. Our results use cluster expansion techniques adapted to the dynamical setting, for which we give a novel proof of their convergence. This has important physical consequences besides our efficient algorithms. In particular, we establish a novel quantum speed limit, a bound on dynamical phase transitions, and a concentration bound for product states evolved for short times.","PeriodicalId":74587,"journal":{"name":"PRX quantum : a Physical Review journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47771310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Crystalline Quantum Circuits 晶体量子电路

PRX quantum : a Physical Review journal Pub Date : 2022-10-19 DOI: 10.1103/PRXQuantum.4.030313

G. M. Sommers, D. Huse, M. Gullans

{"title":"Crystalline Quantum Circuits","authors":"G. M. Sommers, D. Huse, M. Gullans","doi":"10.1103/PRXQuantum.4.030313","DOIUrl":"https://doi.org/10.1103/PRXQuantum.4.030313","url":null,"abstract":"Random quantum circuits continue to inspire a wide range of applications in quantum information science and many-body quantum physics, while remaining analytically tractable through probabilistic methods. Motivated by an interest in deterministic circuits with similar applications, we construct classes of textit{nonrandom} unitary Clifford circuits by imposing translation invariance in both time and space. Further imposing dual-unitarity, our circuits effectively become crystalline spacetime lattices whose vertices are SWAP or iSWAP two-qubit gates and whose edges may contain one-qubit gates. One can then require invariance under (subgroups of) the crystal's point group. Working on the square and kagome lattices, we use the formalism of Clifford quantum cellular automata to describe operator spreading, entanglement generation, and recurrence times of these circuits. A full classification on the square lattice reveals, of particular interest, a\"nonfractal good scrambling class\"with dense operator spreading that generates codes with linear contiguous code distance and high performance under erasure errors at the end of the circuit. We also break unitarity by adding spacetime-translation-invariant measurements and find a class of such circuits with fractal dynamics.","PeriodicalId":74587,"journal":{"name":"PRX quantum : a Physical Review journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42097423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Absence of Localization in Two-Dimensional Clifford Circuits 二维Clifford电路的局部化缺失

PRX quantum : a Physical Review journal Pub Date : 2022-10-18 DOI: 10.1103/PRXQuantum.4.030302

Tom Farshi, Jonas Richter, D. Toniolo, A. Pal, L. Masanes

引用次数: 4

Protocols for Rydberg Entangling Gates Featuring Robustness against Quasistatic Errors 具有抗准静态误差鲁棒性的Rydberg纠缠门协议

PRX quantum : a Physical Review journal Pub Date : 2022-10-17 DOI: 10.1103/PRXQuantum.4.020335

C. Fromonteil, D. Bluvstein, H. Pichler

引用次数: 9

Measurement-Induced Phase Transitions on Dynamical Quantum Trees 动态量子树上的测量诱导相变

PRX quantum : a Physical Review journal Pub Date : 2022-10-13 DOI: 10.1103/PRXQuantum.4.030333

Xiao-Min Feng, B. Skinner, A. Nahum

{"title":"Measurement-Induced Phase Transitions on Dynamical Quantum Trees","authors":"Xiao-Min Feng, B. Skinner, A. Nahum","doi":"10.1103/PRXQuantum.4.030333","DOIUrl":"https://doi.org/10.1103/PRXQuantum.4.030333","url":null,"abstract":"Monitored many-body systems fall broadly into two dynamical phases, ``entangling'' or ``disentangling'', separated by a transition as a function of the rate at which measurements are made on the system. Producing an analytical theory of this measurement-induced transition is an outstanding challenge. Recent work made progress in the context of tree tensor networks, which can be related to all-to-all quantum circuit dynamics with forced (postselected) measurement outcomes. So far, however, there are no exact solutions for dynamics of spin-1/2 degrees of freedom (qubits) with ``real'' measurements, whose outcome probabilities are sampled according to the Born rule. Here we define dynamical processes for qubits, with real measurements, that have a tree-like spacetime interaction graph, either collapsing or expanding the system as a function of time. The former case yields an exactly solvable measurement transition. We explore these processes analytically and numerically, exploiting the recursive structure of the tree. We compare the case of ``real'' measurements with the case of ``forced'' measurements. Both cases show a transition at a nontrivial value of the measurement strength, with the real measurement case exhibiting a smaller entangling phase. Both exhibit exponential scaling of the entanglement near the transition, but they differ in the value of a critical exponent. An intriguing difference between the two cases is that the real measurement case lies at the boundary between two distinct types of critical scaling. On the basis of our results we propose a protocol for realizing a measurement phase transition experimentally via an expansion process.","PeriodicalId":74587,"journal":{"name":"PRX quantum : a Physical Review journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47547376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Optimizing Rydberg Gates for Logical-Qubit Performance 优化Rydberg门的逻辑量子比特性能

PRX quantum : a Physical Review journal Pub Date : 2022-10-13 DOI: 10.1103/PRXQuantum.4.020336

Sven Jandura, J. Thompson, G. Pupillo

{"title":"Optimizing Rydberg Gates for Logical-Qubit Performance","authors":"Sven Jandura, J. Thompson, G. Pupillo","doi":"10.1103/PRXQuantum.4.020336","DOIUrl":"https://doi.org/10.1103/PRXQuantum.4.020336","url":null,"abstract":"Robust gate sequences are widely used to reduce the sensitivity of gate operations to experimental imperfections. Typically, the optimization minimizes the average gate error, however, recent work in quantum error correction has demonstrated that the performance of encoded logical qubits is sensitive to not only the average error rate, but also the type of errors that occur. Here, we present a family of Rydberg blockade gates for neutral atom qubits that are robust against two common, major imperfections: intensity inhomogeneity and Doppler shifts. These gates outperform existing gates for moderate or large imperfections. We also consider the logical performance of these gates in the context of an erasure-biased qubit based on metastable $~^{171}$Yb. In this case, we observe that the robust gates outperform existing gates for even very small values of the imperfections, because they maintain the native large bias towards erasure errors for these qubits. These results significantly reduce the laser stability and atomic temperature requirements to achieve fault-tolerant quantum computing with neutral atoms. The approach of optimizing gates for logical qubit performance may be applied to other qubit platforms.","PeriodicalId":74587,"journal":{"name":"PRX quantum : a Physical Review journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42178895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Quantum Computation of Dynamical Quantum Phase Transitions and Entanglement Tomography in a Lattice Gauge Theory 晶格规范理论中动态量子相变的量子计算和纠缠层析成像

PRX quantum : a Physical Review journal Pub Date : 2022-10-06 DOI: 10.1103/prxquantum.4.030323

N. Mueller, Joseph Carolan, And J. N. Connelly, Z. Davoudi, E. Dumitrescu, Kubra Yeter-Aydeniz

{"title":"Quantum Computation of Dynamical Quantum Phase Transitions and Entanglement Tomography in a Lattice Gauge Theory","authors":"N. Mueller, Joseph Carolan, And J. N. Connelly, Z. Davoudi, E. Dumitrescu, Kubra Yeter-Aydeniz","doi":"10.1103/prxquantum.4.030323","DOIUrl":"https://doi.org/10.1103/prxquantum.4.030323","url":null,"abstract":"Strongly-coupled gauge theories far from equilibrium may exhibit unique features that could illuminate the physics of the early universe and of hadron and ion colliders. Studying real-time phenomena has proven challenging with classical-simulation methods, but is a natural application of quantum simulation. To demonstrate this prospect, we quantum compute non-equal time correlation functions and perform entanglement tomography of non-equilibrium states of a simple lattice gauge theory, the Schwinger model, using a trapped-ion quantum computer by IonQ Inc. As an ideal target for near-term devices, a recently-predicted [Zache et al., Phys. Rev. Lett. 122, 050403 (2019)] dynamical quantum phase transition in this model is studied by preparing, quenching, and tracking the subsequent non-equilibrium dynamics in three ways: i) overlap echos signaling dynamical transitions, ii) non-equal time correlation functions with an underlying topological nature, and iii) the entanglement structure of non-equilibrium states, including entanglement Hamiltonians. These results constitute the first observation of a dynamical quantum phase transition in a lattice gauge theory on a quantum computer, and are a first step toward investigating topological phenomena in nuclear and high-energy physics using quantum technologies.","PeriodicalId":74587,"journal":{"name":"PRX quantum : a Physical Review journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42169775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Floquet Codes without Parent Subsystem Codes 没有父子系统代码的Floquet代码

PRX quantum : a Physical Review journal Pub Date : 2022-10-05 DOI: 10.1103/PRXQuantum.4.020341

M. Davydova, Nathanan Tantivasadakarn, S. Balasubramanian

{"title":"Floquet Codes without Parent Subsystem Codes","authors":"M. Davydova, Nathanan Tantivasadakarn, S. Balasubramanian","doi":"10.1103/PRXQuantum.4.020341","DOIUrl":"https://doi.org/10.1103/PRXQuantum.4.020341","url":null,"abstract":"We propose a new class of error-correcting dynamic codes in two and three dimensions that has no explicit connection to any parent subsystem code. The two-dimensional code, which we call the CSS Floquet code, is geometrically similar to that of the honeycomb code by Hastings and Haah, and also dynamically embeds an instantaneous toric code. However, unlike the honeycomb code it possesses an explicit CSS structure and its gauge checks do not form a subsystem code. Nevertheless, we show that our dynamic protocol conserves logical information and possesses a threshold for error correction. We generalize this construction to three dimensions and obtain a code that fault-tolerantly alternates between realizing two type-I fracton models, the checkerboard and the X-cube model. Finally, we show the compatibility of our CSS Floquet code protocol and the honeycomb code by showing the possibility of randomly switching between the two protocols without information loss while still measuring error syndromes. We call this more general aperiodic structure `dynamic tree codes', which we also generalize to three dimensions. We construct a probabilistic finite automaton prescription that generates dynamic tree codes correcting any single-qubit Pauli errors and can be viewed as a step towards the development of practical fault-tolerant random codes.","PeriodicalId":74587,"journal":{"name":"PRX quantum : a Physical Review journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44400103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Suppressing Quantum Circuit Errors Due to System Variability 抑制系统可变性引起的量子电路误差

PRX quantum : a Physical Review journal Pub Date : 2022-09-30 DOI: 10.1103/PRXQuantum.4.010327

P. Nation, Matthew Treinish

引用次数: 18