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Related papers: A Quantum Computational Perspective on Spread Comp…

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In this work, we investigate the relation between different notions of quantum complexity, namely, circuit and spread complexity and physically meaningful quantities such as the particle content of the quantum state and the variances of…

Quantum Physics · Physics 2025-11-05 Satyaki Chowdhury

We relate the probability distribution of the work done on a statistical system under a sudden quench to the Lanczos coefficients corresponding to evolution under the post-quench Hamiltonian. Using the general relation between the moments…

Quantum Physics · Physics 2023-09-19 Kuntal Pal , Kunal Pal , Ankit Gill , Tapobrata Sarkar

Quantum complexity is a measure of the minimal number of elementary operations required to approximately prepare a given state or unitary channel. Recently, this concept has found applications beyond quantum computing -- in studying the…

Quantum Physics · Physics 2025-01-22 Michał Oszmaniec , Marcin Kotowski , Michał Horodecki , Nicholas Hunter-Jones

Quantum circuit complexity is a fundamental concept whose importance permeates quantum information, computation, many-body physics and high-energy physics. While extensively studied in closed systems, its characterization and behaviors in…

Quantum Physics · Physics 2025-08-28 Zhenyu Du , Zi-Wen Liu , Xiongfeng Ma

We show that the characteristic function of the probability distribution associated with the change of an observable in a two-point measurement protocol with a perturbation can be written as an auto-correlation function between an initial…

Quantum Physics · Physics 2023-11-15 Ankit Gill , Kunal Pal , Kuntal Pal , Tapobrata Sarkar

Quantifying quantum states' complexity is a key problem in various subfields of science, from quantum computing to black-hole physics. We prove a prominent conjecture by Brown and Susskind about how random quantum circuits' complexity…

The concept of quantum complexity has far-reaching implications spanning theoretical computer science, quantum many-body physics, and high energy physics. The quantum complexity of a unitary transformation or quantum state is defined as the…

High Energy Physics - Theory · Physics 2021-08-02 Fernando G. S. L. Brandão , Wissam Chemissany , Nicholas Hunter-Jones , Richard Kueng , John Preskill

Quantum circuits consisting of Clifford and matchgates are two classes of circuits that are known to be efficiently simulatable on a classical computer. We introduce a unified framework that shows in a transparent way the special structure…

Quantum Physics · Physics 2024-05-24 Igor Ermakov , Oleg Lychkovskiy , Tim Byrnes

The complexity of a quantum gate, defined as the minimal number of elementary gates to build it, is an important concept in quantum information and computation. It is shown recently that the complexity of quantum gates built from random…

Quantum Physics · Physics 2022-05-12 Zhi Li

Quantum complexity quantifies the difficulty of preparing a state or implementing a unitary transformation with limited resources. Applications range from quantum computation to condensed matter physics and quantum gravity. We seek to…

In this work, we propose a testing procedure to distinguish between the different approaches for computing complexity. Our test does not require a direct comparison between the approaches and thus avoids the issue of choice of gates, basis,…

High Energy Physics - Theory · Physics 2019-04-15 Tibra Ali , Arpan Bhattacharyya , S. Shajidul Haque , Eugene H. Kim , Nathan Moynihan

We propose a measure of quantum state complexity defined by minimizing the spread of the wave-function over all choices of basis. Our measure is controlled by the "survival amplitude" for a state to remain unchanged, and can be efficiently…

High Energy Physics - Theory · Physics 2022-09-14 Vijay Balasubramanian , Pawel Caputa , Javier Magan , Qingyue Wu

In this work we generalize the concept of modular spread complexity to the cases where the reduced density matrix is non-Hermitian. This notion of complexity and associated Lanczos coefficients contain richer information than the…

High Energy Physics - Theory · Physics 2024-10-08 Aneek Jana , Maitri Ganguli

Quantum circuit complexity-a measure of the minimum number of gates needed to implement a given unitary transformation-is a fundamental concept in quantum computation, with widespread applications ranging from determining the running time…

Quantum Physics · Physics 2024-07-10 Kaifeng Bu , Roy J. Garcia , Arthur Jaffe , Dax Enshan Koh , Lu Li

We show that quantum circuit complexity for the unitary time evolution operator of any time-independent Hamiltonian is bounded by linear growth at early times, independent of any choices of the fundamental gates or cost metric. Deviations…

High Energy Physics - Theory · Physics 2024-10-15 S. Shajidul Haque , Ghadir Jafari , Bret Underwood

In this work, we investigate the impact of conserved charges on the dynamics of spread complexity of quantum states. Building on the notion of symmetry-resolved Krylov complexity [1], we extend the framework to general quantum states and…

High Energy Physics - Theory · Physics 2025-09-17 Pawel Caputa , Giuseppe Di Giulio , Tran Quang Loc

We analyse time evolution of spread complexity (SC) in an isolated interacting quantum many-body system when it is subjected to a sudden quench. The differences in characteristics of the time evolution of the SC for different time scales is…

Quantum Physics · Physics 2023-08-02 Mamta Gautam , Kunal Pal , Kuntal Pal , Ankit Gill , Nitesh Jaiswal , Tapobrata Sarkar

In this paper, the space complexity of nonuniform quantum computations is investigated. The model chosen for this are quantum branching programs, which provide a graphic description of sequential quantum algorithms. In the first part of the…

Quantum Physics · Physics 2007-05-23 M. Sauerhoff , D. Sieling

Recently, several claims have been made that certain fundamental problems of distributed computing, including Leader Election and Distributed Consensus, begin to admit feasible and efficient solutions when the model of distributed…

Quantum Physics · Physics 2009-03-09 Cyril Gavoille , Adrian Kosowski , Marcin Markiewicz

Spectral clustering is a powerful unsupervised machine learning algorithm for clustering data with non convex or nested structures. With roots in graph theory, it uses the spectral properties of the Laplacian matrix to project the data in a…

Quantum Physics · Physics 2021-06-15 Iordanis Kerenidis , Jonas Landman
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