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Related papers: On Krylov Complexity as a Probe of the Quantum Mpe…

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In Hermitian systems, Krylov complexity has emerged as a powerful diagnostic of quantum dynamics, capable of distinguishing chaotic from integrable phases, in agreement with established probes such as spectral statistics and…

High Energy Physics - Theory · Physics 2026-02-12 Matteo Baggioli , Kyoung-Bum Huh , Hyun-Sik Jeong , Xuhao Jiang , Keun-Young Kim , Juan F. Pedraza

A number of recent works have argued that quantum complexity, a well-known concept in computer science that has re-emerged recently in the context of the physics of black holes, may be used as an efficient probe of novel phenomena such as…

High Energy Physics - Theory · Physics 2023-02-08 Pawel Caputa , Nitin Gupta , S. Shajidul Haque , Sinong Liu , Jeff Murugan , Hendrik J. R. Van Zyl

We extend the concept of Krylov complexity to include general unitary evolutions involving multiple generators. This generalization enables us to formulate a framework for generalized Krylov complexity, which serves as a measure of the…

High Energy Physics - Theory · Physics 2025-08-14 Amin Faraji Astaneh , Niloofar Vardian

We explore Krylov complexity for two exactly solvable models, one in the Wheeler-DeWitt (WDW) quantum cosmology and another in loop quantum cosmology (LQC), for a spatially flat, homogeneous, and isotropic universe sourced with a massless…

General Relativity and Quantum Cosmology · Physics 2025-11-25 Meysam Motaharfar , Maxwell R. Siebersma , Parampreet Singh

We study quenched dynamics of fully-connected spin models. The system is prepared in a ground state of the initial Hamiltonian and the Hamiltonian is suddenly changed to a different form. We apply the Krylov subspace method to map the…

Quantum Physics · Physics 2025-08-20 Kazutaka Takahashi

We apply a notion of quantum complexity, called "Krylov complexity", to study the evolution of systems from integrability to chaos. For this purpose we investigate the integrable XXZ spin chain, enriched with an integrability breaking…

High Energy Physics - Theory · Physics 2022-08-12 E. Rabinovici , A. Sánchez-Garrido , R. Shir , J. Sonner

We investigate many-body dynamics where the evolution is governed by unitary circuits through the lens of `Krylov complexity', a recently proposed measure of complexity and quantum chaos. We extend the formalism of Krylov complexity to…

Quantum Physics · Physics 2025-01-30 Philippe Suchsland , Roderich Moessner , Pieter W. Claeys

Krylov complexity has recently been proposed as a quantum probe of chaos. The Krylov exponent characterising the exponential growth of Krylov complexity is conjectured to upper-bound the Lyapunov exponent. We compute the Krylov and the…

High Energy Physics - Theory · Physics 2024-09-13 Shira Chapman , Saskia Demulder , Damián A. Galante , Sameer U. Sheorey , Osher Shoval

The spreading of quantum states in Krylov space under unitary dynamics provides a natural framework for characterizing quantum complexity. Quantifiers of this spreading, such as the spread complexity and the inverse participation ratio,…

Quantum Physics · Physics 2026-03-30 Swati Choudhary , Sukrut Mondkar , Ujjwal Sen

The Mpemba effect, where a system initially farther from equilibrium relaxes faster than one closer to equilibrium, has been extensively studied in classical systems and recently explored in quantum settings. While previous studies of the…

Quantum Physics · Physics 2025-09-30 Tanmay Bhore , Lei Su , Ivar Martin , Aashish A. Clerk , Zlatko Papić

Spread complexity uses the distribution of support of a time-evolving state in the Krylov basis to quantify dispersal across accessible dimensions of a Hilbert space. Here, we describe how variations in initial conditions, the Hamiltonian,…

High Energy Physics - Theory · Physics 2025-11-19 Vijay Balasubramanian , Pawel Caputa , Joan Simón

We study Krylov complexity in various models of quantum field theory: free massive bosons and fermions on flat space and on spheres, holographic models, and lattice models with the UV-cutoff. In certain cases we find asymptotic behavior of…

High Energy Physics - Theory · Physics 2025-08-26 Alexander Avdoshkin , Anatoly Dymarsky , Michael Smolkin

Strongly interacting quantum many-body systems are expected to thermalize, however, some evade thermalization due to symmetries. Quantum synchronization provides one such example of ergodicity breaking, but previous studies have focused on…

Disordered Systems and Neural Networks · Physics 2026-02-13 Nicolas Loizeau , Berislav Buča

We extend the CV conjecture to quantum states of two-mode Hermitian systems using the framework of information geometry. Specifically, we conjecture that the Krylov complexity of a quantum state equals the volume of the Fubini-Study metric.…

High Energy Physics - Theory · Physics 2026-05-22 Ke-Hong Zhai , Lei-Hua Liu , Hai-Qing Zhang

Recently, the concept of spread complexity, Krylov complexity for states, has been introduced as a measure of the complexity and chaoticity of quantum systems. In this paper, we study the spread complexity of the thermofield double state…

High Energy Physics - Theory · Physics 2024-05-27 Kyoung-Bum Huh , Hyun-Sik Jeong , Juan F. Pedraza

The dynamics of quantum systems unfolds within a subspace of the state space or operator space, known as the Krylov space. This review presents the use of Krylov subspace methods to provide an efficient description of quantum evolution and…

We ask whether Krylov complexity is mutually compatible with the circuit and Nielsen definitions of complexity. We show that the Krylov complexities between three states fail to satisfy the triangle inequality and so cannot be a measure of…

High Energy Physics - Theory · Physics 2024-03-20 Sergio E. Aguilar-Gutierrez , Andrew Rolph

Krylov complexity has recently emerged as a new paradigm to characterize quantum chaos in many-body systems. However, which features of Krylov complexity are prerogative of quantum chaotic systems and how they relate to more standard…

High Energy Physics - Theory · Physics 2025-04-11 Matteo Baggioli , Kyoung-Bum Huh , Hyun-Sik Jeong , Keun-Young Kim , Juan F. Pedraza

Krylov complexity is an important dynamical quantity with relevance to the study of operator growth and quantum chaos, and has recently been much studied for various time-independent systems. We initiate the study of K-complexity in…

Quantum Physics · Physics 2023-12-22 Amin A. Nizami , Ankit W. Shrestha

We introduce a one-dimensional (1D) extended quantum breakdown model comprising a fermionic and a spin degree of freedom per site, and featuring a spatially asymmetric breakdown-type interaction between the fermions and spins. We…

Strongly Correlated Electrons · Physics 2024-10-17 Bo-Ting Chen , Abhinav Prem , Nicolas Regnault , Biao Lian