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We introduce quantum circuits in two and three spatial dimensions which are classically simulable, despite producing a high degree of operator entanglement. We provide a partial characterization of these "automaton" quantum circuits, and…

Statistical Mechanics · Physics 2019-12-10 Jason Iaconis , Sagar Vijay , Rahul Nandkishore

We report on recent progress in the study of evolution processes involving degenerate parabolic equations what may exhibit free boundaries. The equations we have selected follow to recent trends in diffusion theory: considering anomalous…

Analysis of PDEs · Mathematics 2016-02-17 Jose Antonio Carrillo , Juan Luis Vazquez

We discuss time dependent quantum systems on bounded domains. Our work may be viewed as a framework for several models, including linear iterations involved in time dependent density functional theory (TDDFT), the Hartree-Fock model, or…

Dynamical Systems · Mathematics 2013-09-17 Joseph W. Jerome , Eric Polizzi

We investigate diffusion-driven instabilities in a FitzHugh-Nagumo reaction-diffusion system with superdiffusive transport, modeled by fractional Laplacian operators with different diffusion orders for the activator and the inhibitor. A…

Pattern Formation and Solitons · Physics 2026-03-04 Rossella Rizzo , Gaetana Gambino , Vincenzo Sciacca , Marco Sammartino

Scrambling is a key concept in the analysis of nonequilibrium properties of quantum many-body systems. Most studies focus on its characterization via out-of-time-ordered correlation functions (OTOCs), particularly through the early-time…

Quantum Physics · Physics 2023-04-14 Sivaprasad Omanakuttan , Karthik Chinni , Philip Daniel Blocher , Pablo M. Poggi

We investigate the dynamics of non-interacting particles in a one-dimensional tight-binding chain in the presence of an electric field with random amplitude drawn from a Gaussian distribution, and explicitly focus on the nature of quantum…

Disordered Systems and Neural Networks · Physics 2025-02-11 Vatsana Tiwari , Sushanta Dattagupta , Devendra Singh Bhakuni , Auditya Sharma

Spreading of bacteria in a highly advective, disordered environment is examined. Predictions of super-diffusive spreading for a simplified reaction-diffusion equation are tested. Concentration profiles display anomalous growth and…

Biological Physics · Physics 2007-05-23 John H. Carpenter , Karin A. Dahmen

This paper concerns a diffusive logistic equation with a free boundary and sign-changing intrinsic growth rate in heterogeneous time-periodic environment, in which the variable intrinsic growth rate may be "very negative" in a "suitable…

Analysis of PDEs · Mathematics 2015-09-22 Mingxin Wang

We propose a nonlocal epidemic model whose spatial domain evolves over time and is represented by $[0,h(t)]$ with $h(t)$ standing for the spreading front of epidemic. It is assumed that the agents can cross the fixed boundary $x=0$, but…

Analysis of PDEs · Mathematics 2024-08-15 Xueping Li , Lei Li

We study the diffusive logistic equation with a free boundary in timeperiodic environment. To understand the effect of the dispersal rate $d$, the original habitat radius $h_0$, the spreading capability $\mu$, and the initial density $u_0$…

Analysis of PDEs · Mathematics 2014-12-09 Qiaoling Chen , Fengquan Li , Feng Wang

We propose a modified version of the Tomlinson model for static friction between two chains of beads. We introduce disorder in terms of vacancies in the chain, and distribute the remaining beads in a scale invariant way. For this we utilize…

Statistical Mechanics · Physics 2011-04-20 Jon Alm Eriksen , Soumyajyoti Biswas , Bikas K. Chakrabarti

We study the asymptotic position distribution of general quantum walks on a lattice, including walks with a random coin, which is chosen from step to step by a general Markov chain. In the unitary (i.e., non-random) case, we allow any…

Quantum Physics · Physics 2011-04-21 Andre Ahlbrecht , Holger Vogts , Albert H. Werner , Reinhard F. Werner

This paper investigates the dynamics of a reaction-diffusion system with two free boundaries, modeling the invasion of two cooperative species, where the free boundaries represent expanding fronts. We first analyze the long-term behavior of…

Analysis of PDEs · Mathematics 2025-11-21 Qian Qin , JinJing Jiao , Zhiguo Wang , Hua Nie

A considerable number of systems have recently been reported in which Brownian yet non-Gaussian dynamics was observed. These are processes characterised by a linear growth in time of the mean squared displacement, yet the probability…

Statistical Mechanics · Physics 2018-11-26 V. Sposini , A. V. Chechkin , F. Seno , G. Pagnini , R. Metzler

We identify a new type of pattern formation in spatially distributed active systems. We simulate one-dimensional two-component systems with predator-prey local interaction and pursuit-evasion taxis between the components. In a sufficiently…

Pattern Formation and Solitons · Physics 2013-05-29 V. N. Biktashev , M. A. Tsyganov

Recent studies found that the diffusive transport of conserved quantities in non-integrable many-body systems has an imprint on quantum entanglement: while the von Neumann entropy of a state grows linearly in time $t$ under a global quench,…

Statistical Mechanics · Physics 2020-07-07 Tianci Zhou , Andreas W. W. Ludwig

In this paper, the authors study the distributed optimal control of a system of three evolutionary equations involving fractional powers of three selfadjoint, monotone, unbounded linear operators having compact resolvents. The system is a…

Optimization and Control · Mathematics 2019-07-25 Pierluigi Colli , Gianni Gilardi , Jürgen Sprekels

We consider the iteration of a unitary operator on a separable Hilbert space and study the spreading rates of the associated discrete-time dynamical system relative to a given orthonormal basis. We prove lower bounds for the transport…

Spectral Theory · Mathematics 2015-11-26 David Damanik , Jake Fillman , Robert Vance

We study theoretically entanglement and operator growth in a spin system coupled to an environment, which is modeled with classical dephasing noise. Using exact numerical simulations we show that the entanglement growth and its fluctuations…

Statistical Mechanics · Physics 2018-11-16 Michael Knap

Out-of-time order correlators (OTOCs) are crucial tools for studying quantum chaos as they show distinct scrambling behavior for chaotic Hamiltonians. We calculate OTOC and analyze the quantum information scrambling in atom-field and…

Quantum Physics · Physics 2025-10-07 Baibhab Bose , Devvrat Tiwari , Subhashish Banerjee