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Related papers: Efficient Unitary T-designs from Random Sums

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In this work we give an efficient construction of unitary $k$-designs using $\tilde{O}(k\cdot poly(n))$ quantum gates, as well as an efficient construction of a parallel-secure pseudorandom unitary (PRU). Both results are obtained by giving…

We study efficient generations of random diagonal-unitary matrices, an ensemble of unitary matrices diagonal in a given basis with randomly distributed phases for their eigenvalues. Despite the simple algebraic structure, they cannot be…

Quantum Physics · Physics 2014-01-31 Yoshifumi Nakata , Mio Murao

We provide new constructions of unitary $t$-designs for general $t$ on one qudit and $N$ qubits, and propose a design Hamiltonian, a random Hamiltonian of which dynamics always forms a unitary design after a threshold time, as a basic…

Quantum Physics · Physics 2017-04-25 Yoshifumi Nakata , Christoph Hirche , Masato Koashi , Andreas Winter

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 consider a class of random quantum circuits where at each step a gate from a universal set is applied to a random pair of qubits, and determine how quickly averages of arbitrary finite-degree polynomials in the matrix elements of the…

Quantum Physics · Physics 2015-05-14 Winton G. Brown , Lorenza Viola

We prove that local random quantum circuits acting on n qubits composed of O(t^{10} n^2) many nearest neighbor two-qubit gates form an approximate unitary t-design. Previously it was unknown whether random quantum circuits were a t-design…

Quantum Physics · Physics 2019-07-11 Fernando G. S. L. Brandao , Aram W. Harrow , Michal Horodecki

Unitary t-designs are distributions on the unitary group whose first t moments appear maximally random. Previous work has established several upper bounds on the depths at which certain specific random quantum circuit ensembles approximate…

The capacity to randomly pick a unitary across the whole unitary group is a powerful tool across physics and quantum information. A unitary $t$-design is designed to tackle this challenge in an efficient way, yet constructions to date rely…

Quantum Physics · Physics 2020-02-19 Rawad Mezher , Joe Ghalbouni , Joseph Dgheim , Damian Markham

The applications of random quantum circuits range from quantum computing and quantum many-body systems to the physics of black holes. Many of these applications are related to the generation of quantum pseudorandomness: Random quantum…

Quantum Physics · Physics 2022-09-14 Jonas Haferkamp

We construct $\varepsilon$-approximate unitary $k$-designs on $n$ qubits in circuit depth $O(\log k \log \log n k / \varepsilon)$. The depth is exponentially improved over all known results in all three parameters $n$, $k$, $\varepsilon$.…

Quantum Physics · Physics 2025-07-22 Laura Cui , Thomas Schuster , Fernando Brandao , Hsin-Yuan Huang

Many quantum information protocols require the implementation of random unitaries. Because it takes exponential resources to produce Haar-random unitaries drawn from the full $n$-qubit group, one often resorts to $t$-designs. Unitary…

In this work, we study distributions of unitaries generated by random quantum circuits containing only symmetry-respecting gates. We develop a unified approach applicable to all symmetry groups and obtain an equation that determines the…

Quantum Physics · Physics 2024-10-16 Hanqing Liu , Austin Hulse , Iman Marvian

Unitary $2$-designs are random unitaries simulating up to the second order statistical moments of the uniformly distributed random unitaries, often referred to as Haar random unitaries. They are used in a wide variety of theoretical and…

Quantum Physics · Physics 2017-06-01 Yoshifumi Nakata , Christoph Hirche , Ciara Morgan , Andreas Winter

Random unitaries are a central object of study in quantum information, with applications to quantum computation, quantum many-body physics, and quantum cryptography. Recent work has constructed unitary designs and pseudorandom unitaries…

Quantum Physics · Physics 2025-09-29 Ben Foxman , Natalie Parham , Francisca Vasconcelos , Henry Yuen

Random unitary matrices sampled from the uniform Haar ensemble have a number of important applications both in cryptography and in the simulation of a variety of fundamental physical systems. Since the Haar ensemble is very expensive to…

Quantum Physics · Physics 2022-03-25 Conrad Strydom , Mark Tame

At its core a $t$-design is a method for sampling from a set of unitaries in a way which mimics sampling randomly from the Haar measure on the unitary group, with applications across quantum information processing and physics. We construct…

Quantum Physics · Physics 2020-03-10 Rawad Mezher , Joe Ghalbouni , Joseph Dgheim , Damian Markham

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

Random quantum circuits are proficient information scramblers and efficient generators of randomness, rapidly approximating moments of the unitary group. We study the convergence of local random quantum circuits to unitary $k$-designs.…

Quantum Physics · Physics 2019-05-31 Nicholas Hunter-Jones

This work focuses on reducing the physical cost of implementing quantum algorithms when using the state-of-the-art fault-tolerant quantum error correcting codes, in particular, those for which implementing the T gate consumes vastly more…

Quantum Physics · Physics 2021-11-24 Michele Mosca , Priyanka Mukhopadhyay

Local random circuits scramble efficiently and accordingly have a range of applications in quantum information and quantum dynamics. With a global $U(1)$ charge however, the scrambling ability is reduced; for example, such random circuits…

Statistical Mechanics · Physics 2025-04-23 Sumner N. Hearth , Michael O. Flynn , Anushya Chandran , Chris R. Laumann
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