arXiv - PHYS - Disordered Systems and Neural Networks最新文献_第3页

Power-law localization in one-dimensional systems with nonlinear disorder under fixed input conditions 固定输入条件下具有非线性无序的一维系统中的幂律局部化

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-18 DOI: arxiv-2408.09339

Ba Phi Nguyen, Kihong Kim

{"title":"Power-law localization in one-dimensional systems with nonlinear disorder under fixed input conditions","authors":"Ba Phi Nguyen, Kihong Kim","doi":"arxiv-2408.09339","DOIUrl":"https://doi.org/arxiv-2408.09339","url":null,"abstract":"We conduct a numerical investigation into wave propagation and localization\u0000in one-dimensional lattices subject to nonlinear disorder, focusing on cases\u0000with fixed input conditions. Utilizing a discrete nonlinear Schr\"odinger\u0000equation with Kerr-type nonlinearity and a random coefficient, we compute the\u0000averages and variances of the transmittance, $T$, and its logarithm, as\u0000functions of the system size $L$, while maintaining constant intensity for the\u0000incident wave. In cases of purely nonlinear disorder, we observe power-law\u0000localization characterized by $langle T rangle propto L^{-gamma_a}$ and\u0000$langle ln T rangle approx -gamma_g ln L$ for sufficiently large $L$. At\u0000low input intensities, a transition from exponential to power-law decay in\u0000$langle T rangle$ occurs as $L$ increases. The exponents $gamma_a$ and\u0000$gamma_g$ are nearly identical, converging to approximately 0.5 as the\u0000strength of the nonlinear disorder, $beta$, increases. Additionally, the\u0000variance of $T$ decays according to a power law with an exponent close to 1,\u0000and the variance of $ln T$ approaches a small constant as $L$ increases. These\u0000findings are consistent with an underlying log-normal distribution of $T$ and\u0000suggest that wave propagation behavior becomes nearly deterministic as the\u0000system size increases. When both linear and nonlinear disorders are present, we\u0000observe a transition from power-law to exponential decay in transmittance with\u0000increasing $L$ when the strength of linear disorder, $V$, is less than $beta$.\u0000As $V$ increases, the region exhibiting power-law localization diminishes and\u0000eventually disappears when $V$ exceeds $beta$, leading to standard Anderson\u0000localization.","PeriodicalId":501066,"journal":{"name":"arXiv - PHYS - Disordered Systems and Neural Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220859","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

Localization and mobility edges in non-Hermitian continuous quasiperiodic systems 非赫米提连续准周期系统中的定位和流动边缘

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-14 DOI: arxiv-2408.07585

Xiang-Ping Jiang, Zhende Liu, Yayun Hu, Lei Pan

{"title":"Localization and mobility edges in non-Hermitian continuous quasiperiodic systems","authors":"Xiang-Ping Jiang, Zhende Liu, Yayun Hu, Lei Pan","doi":"arxiv-2408.07585","DOIUrl":"https://doi.org/arxiv-2408.07585","url":null,"abstract":"The mobility edge (ME) is a fundamental concept in the Anderson localized\u0000systems, which marks the energy separating extended and localized states.\u0000Although the ME and localization phenomena have been extensively studied in\u0000non-Hermitian (NH) quasiperiodic tight-binding models, they remain limited to\u0000NH continuum systems. Here, we investigate the ME and localization properties\u0000of a one-dimensional (1D) NH quasiperiodic continuous system, which is\u0000described by a Schr{\"o}dinger equation with an imaginary vector potential and\u0000an incommensurable one-site potential. We find that the ME is located in the\u0000real spectrum and falls between the localized and extended states.\u0000Additionally, we show that under the periodic boundary condition, the energy\u0000spectrum always exhibits an open curve representing high-energy extended\u0000electronic states characterized by a non-zero integer winding number. This\u0000complex spectrum topology is closely connected with the non-Hermitian skin\u0000effect (NHSE) observed under open boundary conditions, where the eigenstates of\u0000the bulk bands accumulate at the boundaries. Furthermore, we analyze the\u0000critical behavior of the localization transition and obtain critical potential\u0000amplitude accompanied by the universal critical exponent $nu simeq 1/3$. Our\u0000study provides valuable inspiration for exploring MEs and localization\u0000behaviors in NH quasiperiodic continuous systems.","PeriodicalId":501066,"journal":{"name":"arXiv - PHYS - Disordered Systems and Neural Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220865","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

Graph-Based Feature Engineering to Predict the Dynamical Properties of Condensed Matter 基于图谱的特征工程预测凝聚态物质的动态特性

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-12 DOI: arxiv-2408.06016

An Wang, Gabriele C. Sosso

引用次数: 0

Multifractal critical phase driven by coupling quasiperiodic systems to electromagnetic cavities 准周期系统与电磁腔耦合驱动的多分形临界相位

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-12 DOI: arxiv-2408.06496

Thales F. Macedo, Julián Faúndez, Raimundo R. dos Santos, Natanael C. Costa, Felipe A. Pinheiro

{"title":"Multifractal critical phase driven by coupling quasiperiodic systems to electromagnetic cavities","authors":"Thales F. Macedo, Julián Faúndez, Raimundo R. dos Santos, Natanael C. Costa, Felipe A. Pinheiro","doi":"arxiv-2408.06496","DOIUrl":"https://doi.org/arxiv-2408.06496","url":null,"abstract":"We theoretically investigate the effects of criticality and multifractal\u0000states in a one-dimensional Aubry-Andre-Harper model coupled to electromagnetic\u0000cavities. We focus on two specific cases where the phonon frequencies are\u0000$omega_{0}=1$ and $omega_{0}=2$, respectively. Phase transitions are analyzed\u0000using both the average and minimum inverse participation ratio to identify\u0000metallic, fractal, and insulating states. We provide numerical evidence to show\u0000that the presence of the optical cavity induces a critical, intermediate phase\u0000in between the extended and localized phases, hence drastically modifying the\u0000traditional transport phase diagram of the Aubry-Andre-Harper model, in which\u0000critical states can only exist at the well-defined metal-insulator critical\u0000point. We also investigate the probability distribution of the inverse\u0000participation ratio and conduct a multifractal analysis to characterize the\u0000nature of the critical phase, in which we show that extended, localized, and\u0000fractal eigenstates coexist. Altogether our findings reveal the pivotal role\u0000that the coupling to electromagnetic cavities plays in tailoring critical\u0000transport phenomena at the microscopic level of the eigenstates.","PeriodicalId":501066,"journal":{"name":"arXiv - PHYS - Disordered Systems and Neural Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220866","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

Glassy Dynamics from First-Principles Simulations 来自第一原理模拟的玻璃动力学

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-10 DOI: arxiv-2408.05528

Florian Pabst, Stefano Baroni

引用次数: 0

Noise-augmented Chaotic Ising Machines for Combinatorial Optimization and Sampling 用于组合优化和采样的噪声增强混沌伊辛机

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-08 DOI: arxiv-2408.04744

Kyle Lee, Shuvro Chowdhury, Kerem Y. Camsari

{"title":"Noise-augmented Chaotic Ising Machines for Combinatorial Optimization and Sampling","authors":"Kyle Lee, Shuvro Chowdhury, Kerem Y. Camsari","doi":"arxiv-2408.04744","DOIUrl":"https://doi.org/arxiv-2408.04744","url":null,"abstract":"The rise of domain-specific computing has led to great interest in Ising\u0000machines, dedicated hardware accelerators tailored to solve combinatorial\u0000optimization and probabilistic sampling problems. A key element of Ising\u0000machines is stochasticity, which enables a wide exploration of configurations,\u0000thereby helping avoid local minima. Here, we evaluate and improve the\u0000previously proposed concept of coupled chaotic bits (c-bits) that operate\u0000without any explicit stochasticity. We show that augmenting chaotic bits with\u0000stochasticity leads to better algorithmic scaling in combinatorial optimization\u0000problems, comparable to the performance of probabilistic bits (p-bits) which\u0000have explicit randomness in their update rules. We first demonstrate that\u0000c-bits surprisingly follow the quantum Boltzmann law in a 1D transverse field\u0000Ising model, despite the lack of explicit randomness. We then show that c-bits\u0000exhibit critical dynamics similar to those of stochastic p-bits in 2D Ising and\u00003D spin glass models, with promising potential to solve challenging\u0000optimization problems. Finally, we propose a noise-augmented version of coupled\u0000c-bits via the powerful adaptive parallel tempering algorithm (APT). The\u0000noise-augmented c-bit algorithm outperforms fully deterministic c-bits running\u0000versions of the simulated annealing algorithm. Chaotic Ising machines closely\u0000resemble coupled oscillator-based Ising machines, as both schemes exploit\u0000nonlinear dynamics for computation. Oscillator-based Ising machines may greatly\u0000benefit from our proposed algorithm, which runs replicas at constant\u0000temperature, eliminating the need to globally modulate coupling strengths.\u0000Mixing stochasticity with deterministic c-bits creates a powerful hybrid\u0000computing scheme that can bring benefits in scaled, asynchronous, and massively\u0000parallel hardware implementations.","PeriodicalId":501066,"journal":{"name":"arXiv - PHYS - Disordered Systems and Neural Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932127","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

Revisiting multiple trapping and release electronic transport in amorphous semiconductors exemplified by a-Si:H 重新审视非晶半导体中的多重捕获和释放电子传输，以 a-Si:H 为例

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-07 DOI: arxiv-2408.03678

Yuezhou Luo, Andrew John Flewitt

{"title":"Revisiting multiple trapping and release electronic transport in amorphous semiconductors exemplified by a-Si:H","authors":"Yuezhou Luo, Andrew John Flewitt","doi":"arxiv-2408.03678","DOIUrl":"https://doi.org/arxiv-2408.03678","url":null,"abstract":"Multiple trapping and release (MTR) is a typical transport mechanism of\u0000electron carriers in amorphous and other disordered semiconductors where\u0000localized states are significant. Quantitative description of MTR, however, has\u0000been based on an \"abrupt\" mobility edge model, which relies on two underpinning\u0000simplifications: (i) states above the conduction band mobility edge are\u0000extended and any of them is omnipresent in space, whereas states below the\u0000mobility edge are localized and they exist in space as pointlike sites; (ii)\u0000all states are evenly distributed in space, and the local density of states\u0000(DOS) distribution is spatially invariant. The prequel to this paper [Y. Luo\u0000and A. J. Flewitt, Phys. Rev. B 109, 104203 (2024)] demonstrates that neither\u0000of these simplifications is valid. Hence, this paper reinvestigates MTR\u0000transport and focuses on two similar scenarios: steady DC conduction and\u0000non-dispersive time-of-flight conduction. We have managed to reveal that,\u0000first, the experimentally measured mobility edge is an effective quantity which\u0000is different from the actual critical energy that demarcates extended states\u0000and localized states of an amorphous semiconductor. Second, the experimentally\u0000derived extended-state mobility is also an effective quantity which turns out\u0000to be higher than the actual mobility of free electrons in the material. These\u0000two effective quantities are quantified using the hydrogenated amorphous\u0000silicon (a-Si:H) discussed in the prequel paper as an example.","PeriodicalId":501066,"journal":{"name":"arXiv - PHYS - Disordered Systems and Neural Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932118","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

Large time effective kinetics $β$-function for quantum (2+p)-spin glass 量子（2+p）-自旋玻璃的大时间有效动力学β$函数

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-05 DOI: arxiv-2408.02602

Vincent Lahoche, Dine Ousmane Samary, Parham Radpay

引用次数: 0

Operator space fragmentation in perturbed Floquet-Clifford circuits 扰动 Floquet-Clifford 电路中的算子空间碎片

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-02 DOI: arxiv-2408.01545

Marcell D. Kovács, Christopher J. Turner, Lluis Masanes, Arijeet Pal

{"title":"Operator space fragmentation in perturbed Floquet-Clifford circuits","authors":"Marcell D. Kovács, Christopher J. Turner, Lluis Masanes, Arijeet Pal","doi":"arxiv-2408.01545","DOIUrl":"https://doi.org/arxiv-2408.01545","url":null,"abstract":"Floquet quantum circuits are able to realise a wide range of non-equilibrium\u0000quantum states, exhibiting quantum chaos, topological order and localisation.\u0000In this work, we investigate the stability of operator localisation and\u0000emergence of chaos in random Floquet-Clifford circuits subjected to unitary\u0000perturbations which drive them away from the Clifford limit. We construct a\u0000nearest-neighbour Clifford circuit with a brickwork pattern and study the\u0000effect of including disordered non-Clifford gates. The perturbations are\u0000uniformly sampled from single-qubit unitaries with probability $p$ on each\u0000qubit. We show that the interacting model exhibits strong localisation of\u0000operators for $0 le p < 1$ that is characterised by the fragmentation of\u0000operator space into disjoint sectors due to the appearance of wall\u0000configurations. Such walls give rise to emergent local integrals of motion for\u0000the circuit that we construct exactly. We analytically establish the stability\u0000of localisation against generic perturbations and calculate the average length\u0000of operator spreading tunable by $p$. Although our circuit is not separable\u0000across any bi-partition, we further show that the operator localisation leads\u0000to an entanglement bottleneck, where initially unentangled states remain weakly\u0000entangled across typical fragment boundaries. Finally, we study the spectral\u0000form factor (SFF) to characterise the chaotic properties of the operator\u0000fragments and spectral fluctuations as a probe of non-ergodicity. In the $p =\u00001$ model, the emergence of a fragmentation time scale is found before random\u0000matrix theory sets in after which the SFF can be approximated by that of the\u0000circular unitary ensemble. Our work provides an explicit description of quantum\u0000phases in operator dynamics and circuit ergodicity which can be realised on\u0000current NISQ devices.","PeriodicalId":501066,"journal":{"name":"arXiv - PHYS - Disordered Systems and Neural Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932124","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

Thermal conductivity in modified oxide glasses is governed by modal phase changes 改性氧化物玻璃的导热性受模态相变影响

arXiv - PHYS - Disordered Systems and Neural Networks Pub Date : 2024-08-01 DOI: arxiv-2408.00813

Philip Rasmussen, Søren Strandskov Sørensen

{"title":"Thermal conductivity in modified oxide glasses is governed by modal phase changes","authors":"Philip Rasmussen, Søren Strandskov Sørensen","doi":"arxiv-2408.00813","DOIUrl":"https://doi.org/arxiv-2408.00813","url":null,"abstract":"The thermal conductivity of glasses is well-known to be significantly harder\u0000to theoretically describe compared to crystalline materials. Because of this\u0000fact, the fundamental understanding of thermal conductivity in glasses remain\u0000extremely poor when moving beyond the case of simple glasses, e.g., glassy\u0000SiO$_2$, and into so-called 'modified' oxide glasses, that is, glasses where\u0000other oxides (e.g. alkali oxides) have been added to break up the network and\u0000alter e.g. elastic and thermal properties. This lack of knowledge is apparent\u0000despite how modified glasses comprise the far majority of known glasses. In the\u0000present work we study an archetypical series of sodium silicate\u0000($xtext{Na}_2text{O}text{-}(100text{-}x)text{SiO}_2$) glasses. Analyses of\u0000modal contributions reveal how increasing Na$_2$O content induces increasing\u0000vibrational localization with a change of vibrations to be less ordered, and a\u0000related general decrease in modal contributions to thermal conductivity. We\u0000find the vibrational phases (acoustic vs. optical) of sodium vibrations to be\u0000relatively disordered compared to the network-forming silicon and oxygen\u0000species, explaining how increasing Na$_2$O content decreases thermal\u0000conductivity. Our work sheds new light on the fundamentals of glassy heat\u0000transfer as well as the interplay between thermal conduction and modal\u0000characteristics in glasses.","PeriodicalId":501066,"journal":{"name":"arXiv - PHYS - Disordered Systems and Neural Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932122","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