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Related papers: Realizing Unitary $k$-designs with a Single Quench

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Uniformly random unitaries, i.e. unitaries drawn from the Haar measure, have many useful properties, but cannot be implemented efficiently. This has motivated a long line of research into random unitaries that "look" sufficiently Haar…

Quantum Physics · Physics 2024-04-22 Tony Metger , Alexander Poremba , Makrand Sinha , Henry Yuen

Patterns arise spontaneously in a range of systems spanning the sciences, and their study typically focuses on mechanisms to understand their evolution in space-time. Increasingly, there has been a transition towards controlling these…

Soft Condensed Matter · Physics 2024-10-17 Vishaal Krishnan , Sumit Sinha , L. Mahadevan

We present a procedure to accelerate the relaxation of an open quantum system towards its equilibrium state. The control protocol, termed Shortcut to Equilibration, is obtained by reverse-engineering the non-adiabatic master equation. This…

Quantum Physics · Physics 2021-03-11 Roie Dann , Ander Tobalina , Ronnie Kosloff

This paper presents a sampled-data approach for the robust control of a single qubit (quantum bit). The required robustness is defined using a sliding mode domain and the control law is designed offline and then utilized online with a…

Quantum Physics · Physics 2015-03-20 Daoyi Dong , Ian R. Petersen , Herschel Rabitz

A semi-classical non-Hamiltonian model of a spontaneous collapse of unstable quantum system is given. The time evolution of the system becomes non-Hamiltonian at random instants of transition of pure states to reduced ones, given by a…

Mathematical Physics · Physics 2009-11-11 V. P. Belavkin , P. Staszewski

Long-lived single-frequency oscillations in the local non-equilibrium dynamics of a quantum many-body system is an exceptional phenomenon. In fact, till now, it has never been observed, nor predicted, for the physically relevant case where…

Strongly Correlated Electrons · Physics 2015-10-28 Abolfazl Bayat , Sougato Bose , Henrik Johannesson , Pasquale Sodano

This paper considers a class of uncertain linear quantum systems subject to uncertain perturbations in the system Hamiltonian. We present a method to design a coherent robust H-infinity controller so that the closed loop system is robustly…

Systems and Control · Computer Science 2015-09-10 Chengdi Xiang , Ian R. Petersen , Daoyi Dong

The unitary design formation in random circuits has attracted considerable attention due to its wide range of practical applications and relevance to fundamental physics. While the formation rates in Haar random circuits have been…

Quantum Physics · Physics 2026-02-05 Toshihiro Yada , Ryotaro Suzuki , Yosuke Mitsuhashi , Nobuyuki Yoshioka

We investigate a class of exactly solvable quantum quench protocols with a finite quench rate in systems of one dimensional non-relativistic fermions in external harmonic oscillator or inverted harmonic oscillator potentials, with time…

High Energy Physics - Theory · Physics 2019-10-21 Sumit R. Das , Shaun Hampton , Sinong Liu

We prove a new concentration result for non-catalytic decoupling by showing that, for suitably large $t$, applying a unitary chosen uniformly at random from an approximate $t$-design on a quantum system followed by a fixed quantum operation…

Quantum Physics · Physics 2023-11-15 Aditya Nema , Pranab Sen

We investigate protocols for generating a state $t$-design by using a fixed separable initial state and a diagonal-unitary $t$-design in the computational basis, which is a $t$-design of an ensemble of diagonal unitary matrices with random…

Quantum Physics · Physics 2014-05-27 Yoshifumi Nakata , Masato Koashi , Mio Murao

We investigate circuit complexity of unitaries generated by time evolution of randomly chosen strongly interacting Hamiltonians in finite dimensional Hilbert spaces. Specifically, we focus on two ensembles of random generators -- the so…

Quantum Physics · Physics 2025-03-04 Marcin Kotowski , Michał Oszmaniec , Michał Horodecki

Structured decompositions of a desired unitary operator are employed to derive control schemes that achieve certain control objectives for finite-level quantum systems using only sequences of simple control pulses such as square waves with…

Quantum Physics · Physics 2007-05-23 S. G. Schirmer , A. D. Greentree , V. Ramakrishna , H. Rabitz

Realizing controlled operations is fundamental to the design and execution of quantum algorithms. In quantum simulation and learning of quantum many-body systems, an important subroutine consists of implementing a controlled Hamiltonian…

Quantum Physics · Physics 2025-03-11 Anirban Chowdhury , Ewout van den Berg , Pawel Wocjan

We propose a scheme for the determination of the coupling parameters in a chain of interacting spins. This requires only time-resolved measurements over a single particle, simple data post-processing and no state initialization or prior…

Quantum Physics · Physics 2009-05-12 C. Di Franco , M. Paternostro , M. S. Kim

Quantum sensing harnesses the unique properties of quantum systems to enable precision measurements of physical quantities such as time, magnetic and electric fields, acceleration, and gravitational gradients well beyond the limits of…

Quantum Physics · Physics 2025-07-23 Ivana Nikoloska , Ruud Van Sloun , Osvaldo Simeone

Most classical dynamical systems are chaotic. The trajectories of two identical systems prepared in infinitesimally different initial conditions diverge exponentially with time. Quantum systems, instead, exhibit quasi-periodicity due to…

Non-equilibrium dynamics induced by rapid changes of external parameters is relevant for a wide range of scenarios across many domains of physics. For waves in spatially periodic systems, quenches will alter the bandstructure and generate…

Quantum Physics · Physics 2020-02-19 Sadegh Raeisi , Florian Marquardt

We propose the continuous-variable quantum key distribution protocol based on the Gaussian modulation of a single quadrature of the coherent states of light, which is aimed to provide simplified implementation compared to the symmetrically…

Quantum Physics · Physics 2016-01-12 Vladyslav C. Usenko , Frédéric Grosshans

We study a system of $N$ qubits with a random Hamiltonian obtained by drawing coupling constants from Gaussian distributions in various ways. This results in a rich class of systems which include the GUE and the fixed $q$ SYK theories. Our…

High Energy Physics - Theory · Physics 2023-12-25 Takanori Anegawa , Norihiro Iizuka , Arkaprava Mukherjee , Sunil Kumar Sake , Sandip P. Trivedi
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