arXiv - PHYS - Quantum Physics最新文献

Spin resolved momentum spectra for vacuum pair production via a generalized two level model 通过广义两级模型研究真空对产生的自旋分辨动量谱

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.11833

Orkash Amat, Hong-Hao Fan, Suo Tang, Yong-Feng Huang, Bai-Song Xie

{"title":"Spin resolved momentum spectra for vacuum pair production via a generalized two level model","authors":"Orkash Amat, Hong-Hao Fan, Suo Tang, Yong-Feng Huang, Bai-Song Xie","doi":"arxiv-2409.11833","DOIUrl":"https://doi.org/arxiv-2409.11833","url":null,"abstract":"We have formulated a generalized two level model for studying the pair\u0000production in multidimensional time-dependent electric fields. It can provide\u0000momentum spectra with fully spin resolved components for all possible combined\u0000spin states of the particle and anti-particle simultaneously. Moreover, we have\u0000also investigated the validity of the two level model for fermions (scalar\u0000particles) by comparing the results with those by equal-time\u0000Dirac-Heisenberg-Wigner (Feshbach-Villars-Heisenberg-Wigner) formalism in\u0000different regimes of pair creation, i.e., multiphoton and tunneling dominated\u0000mechanisms. It is found that the results are consistent with each other,\u0000indicating the good approximation of the two level model. In particular, in\u0000terms of the two level model, we found that the contribution of the particle\u0000momentum spectra is the greatest when the spin states of the particle and\u0000anti-particle are parallel with $S=1$. It is believed that by this two level\u0000model one can extend researches on pair production for more different\u0000background fields, such as a slowly varying spatial-temporal one. Many other\u0000interesting phenomena may also be revealed, including the spin-resolved vortex\u0000structure that is contained in the phase feature of the distribution function\u0000of the created pairs.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248114","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: 0

Quantum-like nonlinear interferometry with frequency-engineered classical light 用频率工程经典光进行类量子非线性干涉测量

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.12049

Romain Dalidet, Anthony Martin, Grégory Sauder, Laurent Labonté, Sébastien Tanzilli

{"title":"Quantum-like nonlinear interferometry with frequency-engineered classical light","authors":"Romain Dalidet, Anthony Martin, Grégory Sauder, Laurent Labonté, Sébastien Tanzilli","doi":"arxiv-2409.12049","DOIUrl":"https://doi.org/arxiv-2409.12049","url":null,"abstract":"Quantum interferometry methods exploit quantum resources, such as photonic\u0000entanglement, to enhance phase estimation beyond classical limits. Nonlinear\u0000optics has served as a workhorse for the generation of entangled photon pairs,\u0000ensuring both energy and phase conservation, but at the cost of limited rate\u0000and degraded signal-to-noise ratio compared to laser-based interferometry\u0000approaches. We present a \"quantum-like\" nonlinear optical method that reaches\u0000super-resolution in single-photon detection regime. This is achieved by\u0000replacing photon-pairs by coherent states of light, mimicking quantum\u0000properties through classical nonlinear optics processes. Our scheme utilizes\u0000two high-brightness lasers. This results in a substantially greater\u0000signal-to-noise ratio compared to its quantum counterpart. Such an approach\u0000paves the way to significantly reduced acquisition times, providing a pathway\u0000to explore signals across a broader range of bandwidth. The need to increase\u0000the frequency bandwidth of the quantum sensor significantly motivates the\u0000potential applications of this pathway.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248075","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: 0

Performance of Quantum Approximate Optimization with Quantum Error Detection 具有量子错误检测功能的量子近似优化的性能

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.12104

Zichang He, David Amaro, Ruslan Shaydulin, Marco Pistoia

{"title":"Performance of Quantum Approximate Optimization with Quantum Error Detection","authors":"Zichang He, David Amaro, Ruslan Shaydulin, Marco Pistoia","doi":"arxiv-2409.12104","DOIUrl":"https://doi.org/arxiv-2409.12104","url":null,"abstract":"Quantum algorithms must be scaled up to tackle real-world applications. Doing\u0000so requires overcoming the noise present on today's hardware. The quantum\u0000approximate optimization algorithm (QAOA) is a promising candidate for scaling\u0000up due to its modest resource requirements and documented asymptotic speedup\u0000over state-of-the-art classical algorithms for some problems. However,\u0000achieving better-than-classical performance with QAOA is believed to require\u0000fault tolerance. In this paper, we demonstrate a partially fault-tolerant\u0000implementation of QAOA using the $[[k+2,k,2]]$ ``Iceberg'' error detection\u0000code. We observe that encoding the circuit with the Iceberg code improves the\u0000algorithmic performance as compared to the unencoded circuit for problems with\u0000up to $20$ logical qubits on a trapped-ion quantum computer. Additionally, we\u0000propose and calibrate a model for predicting the code performance, and use it\u0000to characterize the limits of the Iceberg code and extrapolate its performance\u0000to future hardware with improved error rates. In particular, we show how our\u0000model can be used to determine necessary conditions for QAOA to outperform\u0000Goemans-Williamson algorithm on future hardware. Our results demonstrate the\u0000largest universal quantum computing algorithm protected by partially\u0000fault-tolerant quantum error detection on practical applications to date,\u0000paving the way towards solving real-world applications with quantum computers.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268298","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: 0

A Computation-Enhanced High-Dimensional Quantum Gate for Silicon-Vacancy Spins 硅空位自旋的计算增强型高维量子门

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.11757

Gang Fan, Fang-Fang Du

引用次数: 0

Hydrodynamic modes and operator spreading in a long-range center-of-mass-conserving Brownian SYK model 长程质量中心守恒布朗 SYK 模型中的流体力学模式和算子扩散

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.11655

Bai-Lin Cheng, Shao-Kai Jian, Zhi-Cheng Yang

引用次数: 0

On the difference between thermalization in open and isolated quantum systems: a case study 论开放量子系统与孤立量子系统中热化的区别：案例研究

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.11932

Archak Purkayastha, Giacomo Guarnieri, Janet Anders, Marco Merkli

{"title":"On the difference between thermalization in open and isolated quantum systems: a case study","authors":"Archak Purkayastha, Giacomo Guarnieri, Janet Anders, Marco Merkli","doi":"arxiv-2409.11932","DOIUrl":"https://doi.org/arxiv-2409.11932","url":null,"abstract":"Thermalization of isolated and open quantum systems has been studied\u0000extensively. However, being the subject of investigation by different\u0000scientific communities and being analysed using different mathematical tools,\u0000the connection between the isolated (IQS) and open (OQS) approaches to\u0000thermalization has remained opaque. Here we demonstrate that the fundamental\u0000difference between the two paradigms is the order in which the long time and\u0000the thermodynamic limits are taken. This difference implies that they describe\u0000physics on widely different time and length scales. Our analysis is carried out\u0000numerically for the case of a double quantum dot (DQD) coupled to a fermionic\u0000lead. We show how both OQS and IQS thermalization can be explored in this model\u0000on equal footing, allowing a fair comparison between the two. We find that\u0000while the quadratically coupled (free) DQD experiences no isolated\u0000thermalization, it of course does experience open thermalization. For the\u0000non-linearly interacting DQD coupled to fermionic lead, we show by\u0000characterizing its spectral form factor and level spacing distribution, that\u0000the system falls in the twilight zone between integrable and non-integrable\u0000regimes, which we call partially non-integrable. We further evidence that,\u0000despite being only partially non-integrable and thereby falling outside the\u0000remit of the standard eigenstate thermalization hypothesis, it nevertheless\u0000experiences IQS as well as OQS thermalization.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248109","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: 0

Macroscopic QED and noise currents in time-varying media 时变介质中的宏观 QED 和噪声电流

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.11873

S. A. R. Horsley, B. Baker

引用次数: 0

Flexible Fault Tolerant Gate Gadgets 灵活的容错门小工具

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.11616

Eric Kubischta, Ian Teixeira

引用次数: 0

Electric field control for experiments with atoms in Rydberg states 雷德贝格态原子实验的电场控制

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.11865

Aishik Panja, Yupeng Wang, Xinghan Wang, Junjie Wang, Sarthak Subhankar, Qi-Yu Liang

引用次数: 0

Rapid initial state preparation for the quantum simulation of strongly correlated molecules 强相关分子量子模拟的快速初始态准备

arXiv - PHYS - Quantum Physics Pub Date : 2024-09-18 DOI: arxiv-2409.11748

Dominic W. Berry, Yu Tong, Tanuj Khattar, Alec White, Tae In Kim, Sergio Boixo, Lin Lin, Seunghoon Lee, Garnet Kin-Lic Chan, Ryan Babbush, Nicholas C. Rubin

{"title":"Rapid initial state preparation for the quantum simulation of strongly correlated molecules","authors":"Dominic W. Berry, Yu Tong, Tanuj Khattar, Alec White, Tae In Kim, Sergio Boixo, Lin Lin, Seunghoon Lee, Garnet Kin-Lic Chan, Ryan Babbush, Nicholas C. Rubin","doi":"arxiv-2409.11748","DOIUrl":"https://doi.org/arxiv-2409.11748","url":null,"abstract":"Studies on quantum algorithms for ground state energy estimation often assume\u0000perfect ground state preparation; however, in reality the initial state will\u0000have imperfect overlap with the true ground state. Here we address that problem\u0000in two ways: by faster preparation of matrix product state (MPS)\u0000approximations, and more efficient filtering of the prepared state to find the\u0000ground state energy. We show how to achieve unitary synthesis with a Toffoli\u0000complexity about $7 times$ lower than that in prior work, and use that to\u0000derive a more efficient MPS preparation method. For filtering we present two\u0000different approaches: sampling and binary search. For both we use the theory of\u0000window functions to avoid large phase errors and minimise the complexity. We\u0000find that the binary search approach provides better scaling with the overlap\u0000at the cost of a larger constant factor, such that it will be preferred for\u0000overlaps less than about $0.003$. Finally, we estimate the total resources to\u0000perform ground state energy estimation of Fe-S cluster systems, including the\u0000FeMo cofactor by estimating the overlap of different MPS initial states with\u0000potential ground-states of the FeMo cofactor using an extrapolation procedure.\u0000{With a modest MPS bond dimension of 4000, our procedure produces an estimate\u0000of $sim 0.9$ overlap squared with a candidate ground-state of the FeMo\u0000cofactor, producing a total resource estimate of $7.3 times 10^{10}$ Toffoli\u0000gates; neglecting the search over candidates and assuming the accuracy of the\u0000extrapolation, this validates prior estimates that used perfect ground state\u0000overlap. This presents an example of a practical path to prepare states of high\u0000overlap in a challenging-to-compute chemical system.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248104","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: 0