Journal of Physics A最新文献_第2页

Integral representations for products of Airy functions and their application for analysis of the Green’s function for a particle in a uniform static field 艾里函数积的积分表示及其在均匀静态场中质点格林函数分析中的应用

Journal of Physics A Pub Date : 2023-11-09 DOI: 10.1088/1751-8121/ad0b59

Alexander Flegel

引用次数: 1

On Hamiltonian structures of quasi-Painlevé equations 拟painlev<s:1>方程的hamilton结构

Journal of Physics A Pub Date : 2023-11-09 DOI: 10.1088/1751-8121/ad0b5c

Galina Filipuk, Alexander Stokes

引用次数: 0

Eﬀectiveness of the Krotov method in finding controls for open quantum systems Krotov方法在寻找开放量子系统控制中的有效性

Journal of Physics A Pub Date : 2023-11-09 DOI: 10.1088/1751-8121/ad0b5b

Marllos E F Fernandes, Felipe F Fanchini, Emanuel de Lima, Leonardo Kleber Castelano

{"title":"Eﬀectiveness of the Krotov method in finding controls for open quantum systems","authors":"Marllos E F Fernandes, Felipe F Fanchini, Emanuel de Lima, Leonardo Kleber Castelano","doi":"10.1088/1751-8121/ad0b5b","DOIUrl":"https://doi.org/10.1088/1751-8121/ad0b5b","url":null,"abstract":"Abstract We apply the Krotov method for open and closed quantum systems to find optimized controls to manipulate qubit/qutrit systems in the presence of the external environment. In the case of unitary optimization, the Krotov method is first applied to a quantum system neglecting its interaction with the environment. The resulting controls from the unitary optimization are then used to drive the system along with the environmental noise. In the case of non-unitary optimization, the Krotov method already takes into account the noise during the optimization process. We consider two distinct computational tasks: target-state preparation and quantum gate implementation. These tasks are carried out in simple qubit/qutrit systems and also in systems presenting leakage states. For the state preparation cases, the controls from the non-unitary optimization outperform the controls from the unitary optimization. However, as we show here, this is not always true for the implementation of quantum gates. There are some situations where the unitary optimization performs equally well compared to the non-unitary optimization. We verify that these situations correspond to either the absence of leakage states or to the effects of dissipation being spread uniformly over the system, including non-computational levels. For such cases, the quantum gate implementation must cover the entire Hilbert space and there is no way to dodge dissipation. On the other hand, if the subspace containing the computational levels and its complement are differently affected by dissipation, the non-unitary optimization becomes effective.","PeriodicalId":16785,"journal":{"name":"Journal of Physics A","volume":" 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135192026","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: 1

Multidimensional integrable deformations of integrable PDEs 可积偏微分方程的多维可积变形

Journal of Physics A Pub Date : 2023-11-08 DOI: 10.1088/1751-8121/ad0ac8

Matteo Casati, Danda Zhang

引用次数: 1

The classiﬁcation of rebit quantum channels rebit量子通道的分类

Journal of Physics A Pub Date : 2023-11-08 DOI: 10.1088/1751-8121/ad0a82

Michele Aldé, Michel Berthier, Edoardo Provenzi

引用次数: 0

Multisoliton complex systems with explicit superpotential interactions 具有显式超势相互作用的多孤子复杂系统

Journal of Physics A Pub Date : 2023-11-08 DOI: 10.1088/1751-8121/ad0af5

Max A Lohe

{"title":"Multisoliton complex systems with explicit superpotential interactions","authors":"Max A Lohe","doi":"10.1088/1751-8121/ad0af5","DOIUrl":"https://doi.org/10.1088/1751-8121/ad0af5","url":null,"abstract":"Abstract We consider scalar field theories in $1+1$ dimensions with $N$ fields $varphi_1, dots varphi_N$ which interact through a potential&#xD;$V=V(varphi_1, dots varphi_N)$, which is defined in terms of an explicit superpotential $W$. We construct $W$ for any $N$ in terms of a known superpotential $w$ for a single-scalar model, such as that for the sine-Gordon equation or the $varphi^4$ model, leading to an expression for $V$ which has multiple minima that supports solitons. Static solitons which minimize the total energy in each soliton sector appear as solutions of first-order Bogomolny equations, which have a gradient structure. These are identical in form to equations which arise in the context of synchronization phenomena in complex systems, with the space and time variables interchanged. The sine-Gordon superpotential, for example, leads to an explicit periodic superpotential $W$ for $N$ scalar fields, with associated Bogomolny equations that are equivalent to the well-known Kuramoto equations which describe the synchronization of identical phase oscillators on the unit circle. The known asymptotic properties of the Kuramoto system, for both positive and negative coupling constants, ensure that finite-energy solitons exist for any given set of intermediate values imposed at the origin. Besides the models derived from the sine-Gordon equation, we investigate $varphi^4$ and $varphi^6$ models with $N$ scalar fields and show numerically that solitons again exist over a wide range of parameters. We also derive general properties of the elementary meson excitations of the system, in particular we show that meson-soliton bound states exist over a restricted range of mass parameters with respect to an exact solution of the $varphi^6$ system for $N=3$.&#xD;","PeriodicalId":16785,"journal":{"name":"Journal of Physics A","volume":" 23","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135340353","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

NOON state measurement probabilities and outcome fidelities: a Bethe Ansatz approach 正午状态测量概率和结果保真度:Bethe Ansatz方法

Journal of Physics A Pub Date : 2023-11-08 DOI: 10.1088/1751-8121/ad0a71

Lachlan Bennett, Phillip Simon Isaac, Jon Links

引用次数: 0

Can shallow quantum circuits scramble local noise into global white noise? 浅层量子电路能将局部噪声搅乱成全局白噪声吗?

Journal of Physics A Pub Date : 2023-11-08 DOI: 10.1088/1751-8121/ad0ac7

Jonathan Foldager, Bálint Koczor

{"title":"Can shallow quantum circuits scramble local noise into global white noise?","authors":"Jonathan Foldager, Bálint Koczor","doi":"10.1088/1751-8121/ad0ac7","DOIUrl":"https://doi.org/10.1088/1751-8121/ad0ac7","url":null,"abstract":"Abstract Shallow quantum circuits are believed to be the most promising candidates for achieving early practical quantum advantage -- this has motivated the development of a broad range of error mitigation techniques whose performance generally improves when the quantum state is well approximated by a global depolarising (white) noise model. While it has been crucial for demonstrating quantum supremacy that random circuits scramble local noise into global white noise---a property that has been proved rigorously---we investigate to what degree practical shallow quantum circuits scramble local noise into global white noise. We define two key metrics as (a) density matrix eigenvalue uniformity and (b) commutator norm. While the former determines the distance from white noise, the latter determines the performance of purification based error mitigation. We derive analytical approximate bounds on their scaling and find in most cases they nicely match numerical results. On the other hand, we simulate a broad class of practical quantum circuits and find that white noise is in certain cases a bad approximation posing significant limitations on the performance of some of the simpler error mitigation schemes. On a positive note, we find in all cases that the commutator norm is sufficiently small guaranteeing a very good performance of purification-based error mitigation. Lastly, we identify techniques that may decrease both metrics, such as increasing the dimensionality of the dynamical Lie algebra by gate insertions or randomised compiling.","PeriodicalId":16785,"journal":{"name":"Journal of Physics A","volume":" 26","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135341417","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

Duality of O(N) and Sp(N) random tensor models: tensors with symmetries O(N)和Sp(N)随机张量模型的对偶性:具有对称性的张量

Journal of Physics A Pub Date : 2023-11-08 DOI: 10.1088/1751-8121/ad0af4

Keppler, H., Krajewski, T., Muller, T., Tanasa, A.

引用次数: 0

Fluctuation of the phase boundary in the six-vertex model with Domain Wall Boundary Conditions: a Monte Carlo study 具有畴壁边界条件的六顶点模型相边界波动的蒙特卡罗研究

Journal of Physics A Pub Date : 2023-11-07 DOI: 10.1088/1751-8121/ad0a43

Ivar Lyberg, Vladimir Korepin, Jacopo Viti

引用次数: 1