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Related papers: Krylov complexity of density matrix operators

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We explore Krylov complexity in the BMN matrix model following a systematic reduction of it, known as the pulsating fuzzy sphere model. We present an analytical setup that allows us to calculate Lanczos coefficients in both large and small…

High Energy Physics - Theory · Physics 2026-05-12 Dibakar Roychowdhury

We present a general formalism for charecterizing 2-time quantum states, describing pre- and post-selected quantum systems. The most general 2-time state is characterized by a `density vector' that is independent of measurements performed…

Quantum Physics · Physics 2014-01-30 Ralph Silva , Yelena Guryanova , Nicolas Brunner , Noah Linden , Anthony J. Short , Sandu Popescu

We study whether a generic isolated quantum system initially set out of equilibrium can be considered as localized close to its initial state. Our approach considers the time evolution in the Krylov basis, which maps the dynamics onto that…

Quantum Physics · Physics 2024-03-22 Youssef Aziz Alaoui , Bruno Laburthe-Tolra

The concepts of operator size and computational complexity play important roles in the study of quantum chaos and holographic duality because they help characterize the structure of time-evolving Heisenberg operators. It is particularly…

High Energy Physics - Theory · Physics 2021-03-09 Shao-Kai Jian , Brian Swingle , Zhuo-Yu Xian

A review is given of phase properties in molecular wave functions, composed of a number of (and, at least, two) electronic states that become degenerate at some nearby values of the nuclear configuration. Apart from discussing phases and…

Chemical Physics · Physics 2007-05-23 R. Englman , A. Yahalom

Completely positive, trace preserving (CPT) maps and Lindblad master equations are both widely used to describe the dynamics of open quantum systems. The connection between these two descriptions is a classic topic in mathematical physics.…

Mathematical Physics · Physics 2012-02-22 Toby S. Cubitt , Jens Eisert , Michael M. Wolf

We review several statistical complexity measures proposed over the last decade and a half as general indicators of structure or correlation. Recently, Lopez-Ruiz, Mancini, and Calbet [Phys. Lett. A 209 (1995) 321] introduced another…

Statistical Mechanics · Physics 2008-02-03 David P. Feldman , James P. Crutchfield

We quantify the emergent complexity of quantum states near quantum critical points on regular 1D lattices, via complex network measures based on quantum mutual information as the adjacency matrix, in direct analogy to quantifying the…

Statistical Mechanics · Physics 2017-12-06 Marc Andrew Valdez , Daniel Jaschke , David L. Vargas , Lincoln D. Carr

Building on the duality between Krylov complexity and geodesic length in Jackiw-Teitelboim and sine-dilaton gravity, we develop a precise holographic dictionary for quantities in the Krylov subspace of the double-scaled Sachdev-Ye-Kitaev…

High Energy Physics - Theory · Physics 2026-05-15 Yichao Fu , Hyun-Sik Jeong , Keun-Young Kim , Juan F. Pedraza

This work addresses how the growth of invariant operators is influenced by their underlying symmetry structure. For this purpose, we introduce the symmetry-resolved Krylov complexity, which captures the time evolution of each block into…

High Energy Physics - Theory · Physics 2025-10-21 Pawel Caputa , Giuseppe Di Giulio , Tran Quang Loc

The growth of simple operators is essential for the emergence of chaotic dynamics and quantum thermalization. Recent studies have proposed different measures, including the out-of-time-order correlator and Krylov complexity. It is…

Quantum Physics · Physics 2024-04-15 Liangyu Chen , Baoyuan Mu , Huajia Wang , Pengfei Zhang

We study operator spreading in many-body quantum systems by its potential to generate an informationally complete measurement record in quantum tomography. We adopt continuous weak measurement tomography for this purpose. We generate the…

Quantum Physics · Physics 2023-12-20 Abinash Sahu , Naga Dileep Varikuti , Bishal Kumar Das , Vaibhav Madhok

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

In this survey the possible approaches to the description of the evolution of states of quantum many-particle systems by means of the possible modifications of the density operator which kernel known as density matrix are considered. In…

Mathematical Physics · Physics 2020-01-14 V. I. Gerasimenko

We introduce a novel conditional density estimation model termed the conditional density operator (CDO). It naturally captures multivariate, multimodal output densities and shows performance that is competitive with recent neural…

Machine Learning · Computer Science 2019-10-30 Ingmar Schuster , Mattes Mollenhauer , Stefan Klus , Krikamol Muandet

In this paper, we investigate the dynamics of a non-Hermitian SSH model that arises out of the no-click limit of a monitored SSH model in the Krylov space. We find that the saturation timescale of the complexity associated with the spread…

Quantum Physics · Physics 2025-07-22 Nilachal Chakrabarti , Neha Nirbhan , Arpan Bhattacharyya

The IP matrix model is a simple large $N$ quantum mechanical model made up of an adjoint harmonic oscillator plus a fundamental harmonic oscillator. It is a model introduced previously as a toy model of the gauge theory dual of an AdS black…

High Energy Physics - Theory · Physics 2023-06-09 Norihiro Iizuka , Mitsuhiro Nishida

We study the Krylov state complexity of the Sachdev-Ye-Kitaev (SYK) model for $N \le 28$ Majorana fermions with $q$-body fermion interaction with $q=4,6,8$ for a range of sparse parameter $k$ that controls the number of remaining terms in…

High Energy Physics - Theory · Physics 2025-08-25 Raghav G. Jha , Ranadeep Roy

We introduce a class of states of a composite quantum system, the so-called cross states, that turn out to play a major role in the theory of entanglement for a genuinely infinite-dimensional bipartite system. In the case where at least one…

Mathematical Physics · Physics 2026-02-23 Paolo Aniello

Consider the question: what statistical ensemble corresponds to minimal prior knowledge about a quantum system ? For the case where the system is in fact known to be in a pure state there is an obvious answer, corresponding to the unique…

Quantum Physics · Physics 2009-10-31 Michael J. W. Hall