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Related papers: Speed Limits and Scrambling in Krylov Space

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Quantum operator scrambling describes the spreading of local operators into the whole system in the picture of Heisenberg evolution, which is often quantified by the operator size growth. Here we propose a measure of quantum operator…

Quantum Physics · Physics 2025-07-29 Bin Sun , Geng-Bin Cao , Xi-Dan Hu , Dan-Bo Zhang

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

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

Solving short and long time dynamics of closed quantum many-body systems is one of the main challenges of both atomic and condensed matter physics. For locally interacting closed systems, the dynamics of local observables can always be…

Quantum Physics · Physics 2025-11-20 Nicolas Loizeau , Berislav Buča , Dries Sels

The growth of information scrambling, captured by out-of-time-order correlation functions (OTOCs), is a central indicator of the nature of many-body quantum dynamics. Here, we compute analytically the complete time dependence of the OTOC…

High Energy Physics - Theory · Physics 2025-11-21 Antonio M. García-García , Chang Liu , Lucas Sá , Jacobus J. M. Verbaarschot , Jie-ping Zheng

In closed generic many-body systems, unitary evolution disperses local quantum information into highly non-local objects, resulting in thermalization. Such a process is called information scrambling, whose swiftness is quantified by the…

Quantum Physics · Physics 2024-03-12 Pengfei Zhang , Zhenhua Yu

The spreading of quantum information in closed systems, often termed scrambling, is a hallmark of many-body quantum dynamics. In open systems, scrambling competes with noise, errors and decoherence. Here, we provide a universal framework…

Quantum Physics · Physics 2022-08-29 Thomas Schuster , Norman Y. Yao

In closed quantum many-body systems, initially localized information spreads throughout the system and becomes highly complex. This phenomenon, known as information scrambling, is closely related to entropy growth and quantum…

Quantum Physics · Physics 2025-02-12 Yuke Zhang , Zeyu Liu , Shuo Zhang , Langxuan Chen , Pengfei Zhang

Quantum scrambling describes the spreading of local information into many degrees of freedom in quantum systems. This provides the conceptual connection among diverse phenomena ranging from thermalizing quantum dynamics to models of black…

Quantum information scrambling has attracted much attention amid the effort to reconcile the conflict between quantum-mechanical unitarity and the thermalizaiton-irreversibility in many-body systems. Here we propose an unconventional…

Quantum Physics · Physics 2019-09-19 Xiaopeng Li , Guanyu Zhu , Muxin Han , Xin Wang

We investigate the Krylov complexity of Schr\"odinger field theories, focusing on both bosonic and fermionic systems within the grand canonical ensemble that includes a chemical potential. Krylov complexity measures operator growth in…

High Energy Physics - Theory · Physics 2025-03-21 Peng-Zhang He , Hai-Qing Zhang

Quantum Information scrambling (QI-scrambling) is a pivotal area of inquiry within the study of quantum many-body systems. This research derives mathematical upper and lower bounds for the scrambling rate by applying the Maligranda…

Quantum Physics · Physics 2025-07-25 Ahmed Zahia , M. Y. Abd-Rabbou , Atta ur Rahman , Cong Feng Qiao

Krylov complexity, or K-complexity for short, has recently emerged as a new probe of chaos in quantum systems. It is a measure of operator growth in Krylov space, which conjecturally bounds the operator growth measured by the out of time…

High Energy Physics - Theory · Physics 2021-10-04 Anatoly Dymarsky , Michael Smolkin

We demonstrate that time-evolved operators can construct a Krylov space to compute Operator complexity and introduce Krylov observability as a measure of effective phase space dimension in quantum systems. We test Krylov observability in…

Quantum Physics · Physics 2026-03-10 Saud Čindrak , Kathy Lüdge , Lina Jaurigue

Krylov complexity provides a powerful framework for characterizing the dynamical evolution of quantum systems through the spreading of states in Krylov space. The motivation for this is rooted in the optimality of the Krylov basis for the…

Quantum Physics · Physics 2026-03-10 Saud Čindrak , Kathy Lüdge

Krylov complexity measures the spread of the wavefunction in the Krylov basis, which is constructed using the Hamiltonian and an initial state. We investigate the evolution of the maximally entangled state in the Krylov basis for both…

High Energy Physics - Theory · Physics 2023-09-06 Johanna Erdmenger , Shao-Kai Jian , Zhuo-Yu Xian

The emergence of the arrow of time in quantum many-body systems stems from the inherent tendency of Hamiltonian evolution to scramble quantum information and increase entanglement. While, in principle, one might counteract this temporal…

Strongly Correlated Electrons · Physics 2026-02-11 Yu-Chen Li , Tian-Gang Zhou , Shengyu Zhang , Ze Wu , Liqiang Zhao , Haochuan Yin , Xiaoxue An , Hui Zhai , Pengfei Zhang , Xinhua Peng , Jiangfeng Du

We study the operator growth in open quantum systems with dephasing dissipation terms, extending the Krylov complexity formalism of Phys. Rev. X 9, 041017. Our results are based on the study of the dissipative $q$-body Sachdev-Ye-Kitaev…

Quantum Physics · Physics 2023-03-10 Budhaditya Bhattacharjee , Xiangyu Cao , Pratik Nandy , Tanay Pathak

In a locally interacting many-body system, two isolated qubits, separated by a large distance $r$, become correlated and entangled with each other at a time $t \ge r/v$. This finite speed $v$ of quantum information scrambling limits quantum…

Quantum Physics · Physics 2019-12-25 Chi-Fang Chen , Andrew Lucas

In a fast scrambling many-body quantum system, information is spread and entanglement is built up on a timescale that grows logarithmically with the system size. This is of fundamental interest in understanding the dynamics of many-body…

Quantum Physics · Physics 2023-09-07 Sridevi Kuriyattil , Tomohiro Hashizume , Gregory Bentsen , Andrew J. Daley