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We study the role of randomness in the scrambling of quantum information within integrable free-fermionic systems. Considering quadratic Hamiltonians with varying degrees of randomness, we analyze entanglement-based measures to characterize…

Quantum Physics · Physics 2025-11-11 Ali Mollabashi , Mohammad-Javad Vasli

We study the dynamical properties of a strongly scrambling quantum circuit involving a projective measurement on a finite-sized region by studying the operator entanglement entropy and mutual information (OEE and BOMI) of the dual operator…

High Energy Physics - Theory · Physics 2023-04-05 Kanato Goto , Masahiro Nozaki , Kotaro Tamaoka , Mao Tian Tan

Out-of-Time-Order Correlators (OTOCs) quantify quantum information scrambling, but their connection to localized phase-space structures, such as chemical transition states, requires formal development. We derive a leading-order…

Quantum Physics · Physics 2026-04-15 Stephen Wiggins

Scrambling of quantum information in both integrable and nonintegrable Floquet spin systems is studied. Our study employs tripartite mutual information (TMI), with negative TMI serving as an indicator of scrambling, where a more negative…

Quantum Physics · Physics 2025-07-29 Rohit Kumar Shukla

Scrambling, the delocalization of initially localized quantum information, is commonly characterized by the out-of-time ordered correlator (OTOC). Employing the OTOC-Renyi-2 entropy theorem we derive a quantum speed limit for the OTOC,…

Quantum Physics · Physics 2026-05-20 Devjyoti Tripathy , Juzar Thingna , Sebastian Deffner

Operator spreading under unitary time evolution has attracted a lot of attention recently, as a way to probe many-body quantum chaos. While quantities such as out-of-time-ordered correlators (OTOC) do distinguish interacting from…

Strongly Correlated Electrons · Physics 2021-09-17 Javier Lopez-Piqueres , Brayden Ware , Sarang Gopalakrishnan , Romain Vasseur

We prove that the time required for sustained information scrambling in any Hamiltonian quantum system is universally at least logarithmic in the entanglement entropy of scrambled states. This addresses two foundational problems in…

Quantum Physics · Physics 2024-04-25 Amit Vikram , Laura Shou , Victor Galitski

Quantum extreme learning machines (QELMs) leverage untrained quantum dynamics to efficiently process information encoded in input quantum states, avoiding the high computational cost of training more complicated nonlinear models. On the…

Quantum Physics · Physics 2025-02-11 Marco Vetrano , Gabriele Lo Monaco , Luca Innocenti , Salvatore Lorenzo , G. Massimo Palma

We demonstrate analytically and verify numerically that the out-of-time order correlator is given by the thermal average of Loschmidt echo signals. This provides a direct link between the out-of-time-order correlator -- a recently suggested…

Quantum Physics · Physics 2020-04-28 Bin Yan , Lukasz Cincio , Wojciech H. Zurek

Entanglement is a defining feature of many-body quantum systems and is an essential requirement for quantum computing. It is therefore useful to study physical processes which generate entanglement within a large system, as they maybe…

Quantum Physics · Physics 2025-05-16 Gaurav Rudra Malik , Rohit Kumar Shukla , S. Aravinda , Sunil Kumar Mishra

Machine learning has shown significant breakthroughs in quantum science, where in particular deep neural networks exhibited remarkable power in modeling quantum many-body systems. Here, we explore how the capacity of data-driven deep neural…

Quantum Physics · Physics 2024-07-24 Naeimeh Mohseni , Junheng Shi , Tim Byrnes , Michael J. Hartmann

We propose and test logarithmic Krylov (logK) complexity, an operator growth measure akin to Krylov complexity defined through a replica approach, as a viable probe of early-time operator scrambling without false positives. In…

High Energy Physics - Theory · Physics 2026-04-07 Hugo A. Camargo , Yichao Fu , Keun-Young Kim , Yeong Han Park

A time-reversed dynamics unwinds information scrambling, which is induced during the time-forward evolution with a complex Hamiltonian. We show that if the scrambled information is, in addition, partially damaged by a local measurement,…

Quantum Physics · Physics 2020-07-27 Bin Yan , Nikolai A. Sinitsyn

Information scrambling refers to the propagation of information throughout a quantum system. Its study not only contributes to our understanding of thermalization but also has wide implications in quantum information and black hole physics.…

Quantum Physics · Physics 2023-06-12 Zeyu Liu , Pengfei Zhang

Scrambling of quantum information is the process by which information initially stored in the local degrees of freedom of a quantum many-body system spreads over its many-body degrees of freedom, becoming inaccessible to local probes and…

Quantum Physics · Physics 2019-10-09 R. J. Lewis-Swan , A. Safavi-Naini , J. J. Bollinger , A. M. Rey

Out-of-time-ordered correlators (OTOC) are a quantifier of quantum information scrambling and quantum chaos. We propose an efficient quantum algorithm to measure OTOCs that provides an exponential speed-up over the best known classical…

Quantum Physics · Physics 2021-03-17 Sreeram PG , Naga Dileep Varikuti , Vaibhav Madhok

We propose and analyze a versatile and efficient multiparameter quantum sensing protocol, which simultaneously estimates many non-commuting and time-dependent signals that are coherently or incoherently coupled to sensing particles. Even in…

Quantum Physics · Physics 2026-02-02 Wenjie Gong , Bingtian Ye , Daniel Mark , Soonwon Choi

Fast scrambling, quantified by the exponential initial growth of Out-of-Time-Ordered-Correlators (OTOCs), is the ability to efficiently spread quantum correlations among the degrees of freedom of interacting systems, and constitutes a…

Quantum Physics · Physics 2023-05-04 Felix Meier , Mathias Steinhuber , Juan Diego Urbina , Daniel Waltner , Thomas Guhr

Quantum communication holds the potential to revolutionize information transmission by enabling secure data exchange that exceeds the limits of classical systems. One of the key performance metrics in quantum information theory, namely the…

Quantum Physics · Physics 2026-02-20 Hong Niu , Chau Yuen , Alexei Ashikhmin , Lajos Hanzo

We characterize a quantum neural network's error in terms of the network's scrambling properties via the out-of-time-ordered correlator. A network can be trained by optimizing either a loss function or a cost function. We show that, with…

Quantum Physics · Physics 2022-03-23 Roy J. Garcia , Kaifeng Bu , Arthur Jaffe