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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

Quantum ensemble systems arise in a variety of applications, including NMR spectroscopy and robust quantum control. While their theoretical properties have been extensively studied, relatively little attention has been given to the explicit…

Optimization and Control · Mathematics 2025-06-25 Ruikang Liang , Gong Cheng

The development of a large scale quantum computer is a highly sought after goal of fundamental research and consequently a highly non-trivial problem. Scalability in quantum information processing is not just a problem of qubit…

Achieving high-fidelity control of quantum systems is essential for realization of a practical quantum computer. Composite pulse sequences which suppress different types of errors can be nested to suppress a wide variety of errors but the…

Mesoscale and Nanoscale Physics · Physics 2019-12-09 Utkan Güngördü , J. P. Kestner

The nature of randomness and complexity growth in systems governed by unitary dynamics is a fundamental question in quantum many-body physics. This problem has motivated the study of models such as local random circuits and their…

Quantum Physics · Physics 2025-10-10 Laura Cui , Thomas Schuster , Liang Mao , Hsin-Yuan Huang , Fernando Brandao

Holonomic quantum computation exploits a quantum state's non-trivial, matrix-valued geometric phase (holonomy) to perform fault-tolerant computation. Holonomies arising from systems where the Hamiltonian traces a continuous path through…

Quantum Physics · Physics 2022-02-08 Cornelis J. G. Mommers , Erik Sjöqvist

A spatially-selective and internal-state-selective triggering pulse is an important component to realize the unitary dynamical state-locking process which may be used to realize the reversible and unitary halting protocol and construct the…

Quantum Physics · Physics 2013-09-18 Xijia Miao

Adaptive quantum design identifies the best broken-symmetry configurations of atoms and molecules that enable a desired target function response. In this work, numerical optimization is used to design atomic clusters with specified…

Strongly Correlated Electrons · Physics 2009-11-10 Jason Thalken , Yu Chen , A. F. J. Levi , Stephan Haas

As quantum computers and simulators begin to produce results that cannot be verified classically, it becomes imperative to develop a variety of tools to detect and diagnose experimental errors on these devices. While state or process…

Quantum Physics · Physics 2022-12-22 Alaina M. Green , Tanmoy Pandit , C. Huerta Alderete , Norbert M. Linke , Raam Uzdin

Unitary and non-unitary diagonal operators are fundamental building blocks in quantum algorithms with applications in the resolution of partial differential equations, Hamiltonian simulations, the loading of classical data on quantum…

Quantum Physics · Physics 2025-01-22 Julien Zylberman , Ugo Nzongani , Andrea Simonetto , Fabrice Debbasch

Recurrent quantum models (RQMs) realize sequential quantum processes through repeated application of a unitary operation on a memory system coupled with a series of output registers. However, such models often rely on unnecessarily large…

Quantum Physics · Physics 2026-03-11 Chufan Lyu , Ximing Wang , Mile Gu , Thomas J. Elliott , Chengran Yang

Low-frequency time-dependent noise is one of the main obstacles on the road towards a fully scalable quantum computer. The majority of solid-state qubit platforms, from superconducting circuits to spins in semiconductors, are greatly…

Quantum Physics · Physics 2021-10-27 Bikun Li , F. A. Calderon-Vargas , Junkai Zeng , Edwin Barnes

Operator controllability refers to the ability to implement an arbitrary unitary in SU(N) and is a prerequisite for universal quantum computing. Controllability tests can be used in the design of quantum devices to reduce the number of…

Quantum compiling, where a parameterized quantum circuit is trained to learn a target unitary, is an important primitive for quantum computing that can be used as a subroutine to obtain optimal circuits or as a tomographic tool to study the…

Quantum Physics · Physics 2021-11-10 Tyler Volkoff , Zoë Holmes , Andrew Sornborger

We introduce random-LCHS, a circuit-efficient randomized-compilation framework for simulating linear non-unitary dynamics of the form $\partial_t u(t) = -A(t) u(t) + b(t)$ built on the linear combination of Hamiltonian simulation (LCHS). We…

Quantum Physics · Physics 2025-09-11 Songqinghao Yang , Jin-Peng Liu

Maximally entangled bipartite unitary operators or gates find various applications from quantum information to being building blocks of minimal models of many-body quantum chaos, and have been referred to as "dual unitaries". Dual unitary…

Quantum Physics · Physics 2020-08-19 Suhail Ahmad Rather , S. Aravinda , Arul Lakshminarayan

We clarify the mathematical structure underlying unitary $t$-designs. These are sets of unitary matrices, evenly distributed in the sense that the average of any $t$-th order polynomial over the design equals the average over the entire…

Quantum Physics · Physics 2009-11-13 D. Gross , K. Audenaert , J. Eisert

Randomness is an essential tool in many disciplines of modern sciences, such as cryptography, black hole physics, random matrix theory and Monte Carlo sampling. In quantum systems, random operations can be obtained via random circuits…

Quantum Physics · Physics 2017-10-24 Leonardo Banchi , Daniel Burgarth , Michael J. Kastoryano

Quantum computing is usually associated with discrete quantum states and physical quantities possessing discrete eigenvalue spectrum. However, quantum computing in general is any computation accomplished by the exploitation of quantum…

Quantum Physics · Physics 2021-07-06 Samantha Buck , Robin Coleman , Hayk Sargsyan

The capacity to custom tailor the properties of quantum matter and materials is a central requirement for enlarging their range of possible functionalities. A particularly promising route is the use of driving protocols to engineer specific…

Quantum Physics · Physics 2025-02-19 Zhanpeng Fu , Roderich Moessner , Hongzheng Zhao , Marin Bukov