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We apply Tsallis's q-indexed nonextensive entropy to formulate a random matrix theory (RMT), which may be suitable for systems with mixed regular-chaotic dynamics. We consider the super-extensive regime of q < 1. We obtain analytical…

Mathematical Physics · Physics 2011-12-06 A. Abd El-Hady , A. Y. Abul-Magd

We consider learning the structures of Gaussian latent tree models with vector observations when a subset of them are arbitrarily corrupted. First, we present the sample complexities of Recursive Grouping (RG) and Chow-Liu Recursive…

Machine Learning · Statistics 2021-10-26 Fengzhuo Zhang , Vincent Y. F. Tan

Recent studies have shown that there is a strong interplay between quantum complexity and quantum chaos. In this work, we consider a new method to study geometric complexity for interacting non-Gaussian quantum mechanical systems to…

High Energy Physics - Theory · Physics 2025-03-27 Arpan Bhattacharyya , Suddhasattwa Brahma , Satyaki Chowdhury , Xiancong Luo

A rich variety of non-equilibrium dynamical phenomena and processes unambiguously calls for the development of general numerical techniques to probe and estimate a complex interplay between spatial and temporal degrees of freedom in…

Quantum Physics · Physics 2025-08-26 E. A. Maletskii , I. A. Iakovlev , V. V. Mazurenko

Fermionic reduced density matrices summarize the key observables in fermionic systems. In electronic systems, the two-particle reduced density matrix (2-RDM) is sufficient to determine the energy and most physical observables of interest.…

Quantum Physics · Physics 2023-06-12 Linqing Peng , Xing Zhang , Garnet Kin-Lic Chan

In this work, we collect data from runs of Krylov subspace methods and pipelined Krylov algorithms in an effort to understand and model the impact of machine noise and other sources of variability on performance. We find large variability…

Mathematical Software · Computer Science 2021-03-24 Hannah Morgan , Patrick Sanan , Matthew G. Knepley , Richard Tran Mills

We investigate the relationship between Krylov complexity and operator quantum speed limits (OQSLs) of the complexity operator and level repulsion in random/integrable matrices and many-body systems. An enhanced level-repulsion corresponds…

Quantum Physics · Physics 2025-04-29 Ankit Gill , Tapobrata Sarkar

The Gaussian kernel is one of the most important kernels, applicable to many research fields, including scientific computing and data science. In this paper, we present asymptotic analysis of the Gaussian kernel matrix in high dimension…

Statistics Theory · Mathematics 2026-02-11 Kensuke Aishima

We develop a recently introduced representation of quantum dynamics based on sampling negative Markov chain processes. By introducing particles and antiparticles, this formalism maps generic quantum dynamics onto a Markov process defined…

Quantum Physics · Physics 2026-04-23 Hugo Lóio , Jacopo De Nardis , Tony Jin

We use supersymmetry to calculate exact spectral densities for a class of complex random matrix models having the form $M=S+LXR$, where $X$ is a random noise part $X$ and $S,L,R$ are fixed structure parts. This is a certain version of the…

Mathematical Physics · Physics 2016-11-02 Jacek Grela , Thomas Guhr

The Gaussian Process Convolution Model (GPCM; Tobar et al., 2015a) is a model for signals with complex spectral structure. A significant limitation of the GPCM is that it assumes a rapidly decaying spectrum: it can only model smooth…

Machine Learning · Statistics 2022-04-15 Wessel P. Bruinsma , Martin Tegnér , Richard E. Turner

In this paper we study the notion of complexity under time evolution in chaotic quantum systems with holographic duals. Continuing on from our previous work, we turn our attention to the issue of Krylov complexity upon the insertion of a…

High Energy Physics - Theory · Physics 2025-03-10 Marco Ambrosini , Eliezer Rabinovici , Adrián Sánchez-Garrido , Ruth Shir , Julian Sonner

This work brings together two powerful concepts in Gaussian processes: the variational approach to sparse approximation and the spectral representation of Gaussian processes. This gives rise to an approximation that inherits the benefits of…

Machine Learning · Statistics 2017-11-09 James Hensman , Nicolas Durrande , Arno Solin

Quantum non-Markovianity of a quantum noisy channel manifests typically as information backflow, characterized by the departure of the intermediate map from complete positivity, though we indicate certain noisy channels that don't exhibit…

We investigate the phase transitions from chaotic to nonchaotic dynamics in a quantum spin chain with a local non-Hermitian disorder, which can be realized with a Rydberg atom array setting. As the disorder strength increases, the emergence…

Quantum Physics · Physics 2025-10-03 Yijia Zhou , Wei Xia , Lin Li , Weibin Li

Recently, a novel measure for the complexity of operator growth is proposed based on Lanczos algorithm and Krylov recursion method. We study this Krylov complexity in quantum mechanical systems derived from some well-known local toric…

High Energy Physics - Theory · Physics 2023-04-27 Bao-ning Du , Min-xin Huang

We address the dynamics of entanglement and quantum discord for two non interacting qubits initially prepared in a maximally entangled state and then subjected to a classical colored noise, i.e. coupled with an external environment…

Quantum Physics · Physics 2013-06-06 C. Benedetti , F. Buscemi , P. Bordone , M. G. A. Paris

We propose a measure, which we call the dissipative spectral form factor (DSFF), to characterize the spectral statistics of non-Hermitian (and non-Unitary) matrices. We show that DSFF successfully diagnoses dissipative quantum chaos, and…

Statistical Mechanics · Physics 2021-11-03 Jiachen Li , Tomaž Prosen , Amos Chan

We obtain analytical approximations for the expectation and variance of the Spectral Kurtosis estimator in the case of Gaussian and coherent transient time domain signals mixed with a quasi-stationary Gaussian background, which are suitable…

Instrumentation and Methods for Astrophysics · Physics 2016-03-23 Gelu M. Nita

We study a system of spins (qubits) coupled to a common noisy environment, each precessing at its own frequency. The correlated noise experienced by the spins implies long-lived correlations that relax only due to the differing frequencies.…

Quantum Physics · Physics 2018-03-01 Daniel A. Rowlands , Austen Lamacraft