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Consider a bipartite system, of which one subsystem, A, undergoes a physical evolution separated from the other subsystem, R. One may ask under which conditions this evolution destroys all initial correlations between the subsystems A and…

Quantum Physics · Physics 2013-05-24 Oleg Szehr , Frédéric Dupuis , Marco Tomamichel , Renato Renner

We investigate decoupling, one of the most important primitives in quantum Shannon theory, by replacing the uniformly distributed random unitaries commonly used to achieve the protocol, with repeated applications of random unitaries…

Quantum Physics · Physics 2017-07-27 Yoshifumi Nakata , Christoph Hirche , Ciara Morgan , Andreas Winter

It was recently observed that in certain thermalizing many-body systems, measuring the complement of a subsystem that thermalized to infinite temperature in a suitable orthonormal basis gives rise to approximate quantum state k-designs as…

Quantum Physics · Physics 2022-02-04 Henrik Wilming , Ingo Roth

Entangled photons are widely used in quantum technologies. Many photonic experiments generate them with probabilistic photon-pair sources that can be modeled as squeeze operators. In practice, these sources are usually treated in the…

Quantum Physics · Physics 2026-05-05 Carlos Ruiz-Gonzalez , Mario Krenn , Xuemei Gu

Understanding how fast physical systems can resemble Haar-random unitaries is a fundamental question in physics. Many experiments of interest in quantum gravity and many-body physics, including the butterfly effect in quantum information…

Quantum Physics · Physics 2025-10-01 Thomas Schuster , Fermi Ma , Alex Lombardi , Fernando Brandao , Hsin-Yuan Huang

Decoupling has become a central concept in quantum information theory with applications including proving coding theorems, randomness extraction and the study of conditions for reaching thermal equilibrium. However, our understanding of the…

Quantum Physics · Physics 2018-02-06 Winton Brown , Omar Fawzi

Black hole evaporation is one of the most striking phenomena at the interface between gravity and quantum physics. In Hawking's semi-classical treatment, where matter is quantum mechanical and the spacetime is definite and classical,…

General Relativity and Quantum Cosmology · Physics 2025-07-24 Ali Akil , Lorenzo Giannelli , Leonardo Modesto , Oscar Dahlsten , Giulio Chiribella , Caslav Brukner

We first propose and study a quantum toy model of black hole dynamics. The model is unitary, displays quantum thermalization, and the Hamiltonian couples every oscillator with every other, a feature intended to emulate the color sector…

High Energy Physics - Theory · Physics 2016-12-21 Javier M. Magan

For finite-dimensional quantum systems, such as qubits, a well established strategy to protect such systems from decoherence is dynamical decoupling. However many promising quantum devices, such as oscillators, are infinite dimensional, for…

Quantum Physics · Physics 2017-04-05 Christian Arenz , Robin Hillier , Daniel Burgarth

Unitary Designs have become a vital tool for investigating pseudorandomness since they approximate the statistics of the uniform Haar ensemble. Despite their central role in quantum information, their relation to quantum chaotic evolution…

Quantum Physics · Physics 2025-02-19 Michele Fava , Jorge Kurchan , Silvia Pappalardi

Realizing the theoretical promise of quantum computers will require overcoming decoherence. Here we demonstrate numerically that high fidelity quantum gates are possible within a framework of quantum dynamical decoupling. Orders of…

Quantum Physics · Physics 2010-12-16 Jacob R. West , Daniel A. Lidar , Bryan H. Fong , Mark F. Gyure

Epsilon-nets and approximate unitary $t$-designs are natural notions that capture properties of unitary operations relevant for numerous applications in quantum information and quantum computing. The former constitute subsets of unitary…

Quantum Physics · Physics 2021-11-02 Michał Oszmaniec , Adam Sawicki , Michał Horodecki

Entanglement is a key resource for quantum information technologies ranging from quantum sensing to quantum computing. Conventionally, the entanglement between two coupled qubits is established at the time scale of the inverse of the…

Quantum Physics · Physics 2023-09-12 Zeng-Zhao Li , Weijian Chen , Maryam Abbasi , Kater W. Murch , K. Birgitta Whaley

Deep thermalization refers to the emergence of Haar-like randomness from quantum systems upon partial measurements. As a generalization of quantum thermalization, it is often associated with high complexity and entanglement. Here, we…

Quantum Physics · Physics 2025-11-24 Shantanav Chakraborty , Soonwon Choi , Soumik Ghosh , Tudor Giurgică-Tiron

Random unitaries are useful in quantum information and related fields, but hard to generate with limited resources. An approximate unitary $k$-design is an ensemble of unitaries with an underlying measure over which the average is close to…

Quantum Physics · Physics 2026-02-09 Nicholas LaRacuente , Felix Leditzky

The discretization approximation method commonly used to simulate the dynamics of quantum system coupled to the environment in continuum often suffers from the periodically partial recovery of initial state because of the effect of finite…

Quantum Physics · Physics 2025-05-07 H. T. Cui , Y. A. Yan , M. Qin , X. X. Yi

Strongly correlated systems far from equilibrium can exhibit scaling solutions with a dynamically generated weak coupling. We show this by investigating isolated systems described by relativistic quantum field theories for initial…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. Berges , A. Rothkopf , J. Schmidt

We present a systematic hierarchy of approximations for {\it local} exact-decoupling of four-component quantum chemical Hamiltonians based on the Dirac equation. Our ansatz reaches beyond the trivial local approximation that is based on a…

Chemical Physics · Physics 2012-06-28 Daoling Peng , Markus Reiher

Having a broad range of methods available for implementing unitary operations is crucial for quantum information tasks. We study a dissipative process commonly used to describe dissipatively coupled systems and show that the process can…

Quantum Physics · Physics 2020-02-12 C. Arenz , A. Metelmann

Dynamical decoupling is a coherent control technique where the intrinsic and extrinsic couplings of a quantum system are effectively averaged out by application of specially designed driving fields (refocusing pulse sequences). This entails…

Quantum Physics · Physics 2009-11-13 Leonid P. Pryadko , Gregory Quiroz
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