Quantum最新文献_第4页

The Dirac Vacuum in Discrete Spacetime 离散时空中的狄拉克真空

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-09-03 DOI: 10.22331/q-2025-09-03-1845

Chaitanya Gupta, Anthony J. Short

引用次数: 0

Batched Line Search Strategy for Navigating through Barren Plateaus in Quantum Circuit Training 量子电路训练中穿越贫瘠高原的批线搜索策略

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-29 DOI: 10.22331/q-2025-08-29-1841

Jakab Nádori, Gregory Morse, Barna Fülöp Villám, Zita Majnay-Takács, Zoltán Zimborás, Péter Rakyta

{"title":"Batched Line Search Strategy for Navigating through Barren Plateaus in Quantum Circuit Training","authors":"Jakab Nádori, Gregory Morse, Barna Fülöp Villám, Zita Majnay-Takács, Zoltán Zimborás, Péter Rakyta","doi":"10.22331/q-2025-08-29-1841","DOIUrl":"https://doi.org/10.22331/q-2025-08-29-1841","url":null,"abstract":"Variational quantum algorithms are viewed as promising candidates for demonstrating quantum advantage on near-term devices. These approaches typically involve the training of parameterized quantum circuits through a classical optimization loop. However, they often encounter challenges attributed to the exponentially diminishing gradient components, known as the barren plateau (BP) problem. This work introduces a novel optimization approach designed to alleviate the adverse effects of BPs during circuit training. In contrast to conventional gradient descent methods with a small learning parameter, our approach relies on making a finite hops along the search direction determined on a randomly chosen subsets of the free parameters. The optimization search direction, together with the range of the search, is determined by the distant features of the cost-function landscape. This enables the optimization path to navigate around barren plateaus without the need for external control mechanisms. We have successfully applied our optimization strategy to quantum circuits comprising 21 qubits and 15000 entangling gates, demonstrating robust resistance against BPs. Additionally, we have extended our optimization strategy by incorporating an evolutionary selection framework, enhancing its ability to avoid local minima in the landscape. The modified algorithm has been successfully utilized in quantum gate synthesis applications, showcasing a significantly improved efficiency in generating highly compressed quantum circuits compared to traditional gradient-based optimization approaches.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"21 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915811","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

Targeted Clifford logical gates for hypergraph product codes 目标Clifford逻辑门超图产品代码

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-29 DOI: 10.22331/q-2025-08-29-1842

Adway Patra, Alexander Barg

引用次数: 0

Reduced Sampling Overhead for Probabilistic Error Cancellation by Pauli Error Propagation 利用泡利误差传播减少概率误差消除的采样开销

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-29 DOI: 10.22331/q-2025-08-29-1840

Timon Scheiber, Paul Haubenwallner, Matthias Heller

引用次数: 0

Lindblad engineering for quantum Gibbs state preparation under the eigenstate thermalization hypothesis 本征态热化假设下量子吉布斯态制备的Lindblad工程

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-29 DOI: 10.22331/q-2025-08-29-1843

Eric Brunner, Luuk Coopmans, Gabriel Matos, Matthias Rosenkranz, Frederic Sauvage, Yuta Kikuchi

{"title":"Lindblad engineering for quantum Gibbs state preparation under the eigenstate thermalization hypothesis","authors":"Eric Brunner, Luuk Coopmans, Gabriel Matos, Matthias Rosenkranz, Frederic Sauvage, Yuta Kikuchi","doi":"10.22331/q-2025-08-29-1843","DOIUrl":"https://doi.org/10.22331/q-2025-08-29-1843","url":null,"abstract":"Building upon recent progress in Lindblad engineering for quantum Gibbs state preparation algorithms, we propose a simplified protocol that is shown to be efficient under the eigenstate thermalization hypothesis (ETH). The ETH reduces circuit overheads of the Lindblad simulation algorithm and ensures a fast convergence toward the target Gibbs state. Moreover, we show that the realized Lindblad dynamics exhibits an inherent resilience against stochastic noise, opening up the path to a first demonstration on quantum computers. We complement our claims with numerical studies of the algorithm's convergence in various regimes of the mixed-field Ising model. In line with our predictions, we observe a mixing time scaling polynomially with system size when the ETH is satisfied. In addition, we assess the impact of algorithmic and hardware-induced errors on the algorithm's performance by carrying out quantum circuit simulations of our Lindblad simulation protocol with a local depolarizing noise model. This work bridges the gap between recent theoretical advances in dissipative Gibbs state preparation algorithms and their eventual quantum hardware implementation.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"219 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915813","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

Superposition detection and QMA with non-collapsing measurements 非坍缩测量的叠加检测和QMA

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-28 DOI: 10.22331/q-2025-08-28-1839

Roozbeh Bassirian, Kunal Marwaha

引用次数: 0

Preparing low-variance states using a distributed quantum algorithm 使用分布式量子算法制备低方差状态

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-28 DOI: 10.22331/q-2025-08-28-1838

Xiaoyu Liu, Benjamin F. Schiffer, Jordi Tura

引用次数: 0

Resource-efficient algorithm for estimating the trace of quantum state powers 估计量子态功率轨迹的资源高效算法

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-27 DOI: 10.22331/q-2025-08-27-1832

Myeongjin Shin, Junseo Lee, Seungwoo Lee, Kabgyun Jeong

{"title":"Resource-efficient algorithm for estimating the trace of quantum state powers","authors":"Myeongjin Shin, Junseo Lee, Seungwoo Lee, Kabgyun Jeong","doi":"10.22331/q-2025-08-27-1832","DOIUrl":"https://doi.org/10.22331/q-2025-08-27-1832","url":null,"abstract":"Estimating the trace of quantum state powers, $text{Tr}(rho^k)$, for $k$ identical quantum states is a fundamental task with numerous applications in quantum information processing, including nonlinear function estimation of quantum states and entanglement detection. On near-term quantum devices, reducing the required quantum circuit depth, the number of multi-qubit quantum operations, and the copies of the quantum state needed for such computations is crucial. In this work, inspired by the Newton-Girard method, we significantly improve upon existing results by introducing an algorithm that requires only $mathcal{O}(widetilde{r})$ qubits and $mathcal{O}(widetilde{r})$ multi-qubit gates, where $widetilde{r} = minleft{text{rank}(rho), leftlceillnleft({2k}/{epsilon}right)rightrceilright}$. This approach is efficient, as it employs the $tilde{r}$-entangled copy measurement instead of the conventional $k$-entangled copy measurement, while asymptotically preserving the known sample complexity upper bound. Furthermore, we prove that estimating ${text{Tr}(rho^i)}_{i=1}^{tilde{r}}$ is sufficient to approximate $text{Tr}(rho^k)$ even for large integers $k gt widetilde{r}$. This leads to a rank-dependent complexity for solving the problem, providing an efficient algorithm for low-rank quantum states while also improving existing methods when the rank is unknown or when the state is not low-rank. Building upon these advantages, we extend our algorithm to the estimation of $text{Tr}(Mrho^k)$ for arbitrary observables and $text{Tr}(rho^k sigma^l)$ for multiple quantum states.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"16 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144905881","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

Riemannian quantum circuit optimization based on matrix product operators 基于矩阵积算子的黎曼量子电路优化

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-27 DOI: 10.22331/q-2025-08-27-1833

Isabel Nha Minh Le, Shuo Sun, Christian B. Mendl

{"title":"Riemannian quantum circuit optimization based on matrix product operators","authors":"Isabel Nha Minh Le, Shuo Sun, Christian B. Mendl","doi":"10.22331/q-2025-08-27-1833","DOIUrl":"https://doi.org/10.22331/q-2025-08-27-1833","url":null,"abstract":"We significantly enhance the simulation accuracy of initial Trotter circuits for Hamiltonian simulation of quantum systems by integrating first-order Riemannian optimization with tensor network methods. Unlike previous approaches, our method imposes no symmetry assumptions, such as translational invariance, on the quantum systems. This technique is scalable to large systems through the use of a matrix product operator representation of the reference time evolution propagator. Our optimization routine is applied to various spin chains and fermionic systems described by the transverse-field Ising Hamiltonian, the Heisenberg Hamiltonian, and the spinful Fermi-Hubbard Hamiltonian. In these cases, our approach achieves a relative error improvement of up to four orders of magnitude for systems of 50 qubits, although our method is also applicable to larger systems. Furthermore, we demonstrate the versatility of our method by applying it to molecular systems, specifically lithium hydride, achieving an error improvement of up to eight orders of magnitude. This proof of concept highlights the potential of our approach for broader applications in quantum simulations.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"23 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144905882","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

Minimal criteria for continuous-variable genuine multipartite entanglement 连续变量真多部纠缠的最小准则

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-08-27 DOI: 10.22331/q-2025-08-27-1837

Olga Leskovjanová, Ladislav Mišta Jr.

{"title":"Minimal criteria for continuous-variable genuine multipartite entanglement","authors":"Olga Leskovjanová, Ladislav Mišta Jr.","doi":"10.22331/q-2025-08-27-1837","DOIUrl":"https://doi.org/10.22331/q-2025-08-27-1837","url":null,"abstract":"We derive a set of genuine multi-mode entanglement criteria for second moments of the quadrature operators. The criteria have a common form of the uncertainty relation between sums of variances of position and momentum quadrature combinations. A unique feature of the criteria is that the sums contain the least possible number of variances of at most two-mode combinations. The number of second moments we need to know to apply the criteria thus scales only linearly with the number of modes, as opposed to the quadratic scaling of the already existing criteria. Each criterion is associated with a tree graph, which allowed us to develop a direct method of construction of the criteria based solely on the structure of the underlying tree. The practicality of the proposed criteria is demonstrated by finding a number of examples of Gaussian states of up to six modes, whose genuine multi-mode entanglement is detected by them. The designed criteria are particularly suitable for verification of genuine multipartite entanglement in large multi-mode states or when only a set of two-mode nearest-neighbour marginal covariance matrices of the investigated state is available.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"19 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144905903","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