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Related papers: Anti-concentration is (almost) all you need

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We present a computational problem with the following properties: (i) Every instance can be solved with near-certainty by a constant-depth quantum circuit using only nearest-neighbor gates in 3D even when its implementation is corrupted by…

Quantum Physics · Physics 2023-12-15 Libor Caha , Xavier Coiteux-Roy , Robert Koenig

We present a simple 2d local circuit that implements all-to-all interactions via perturbative gadgets. We find an analytic relation between the values $J_{ij}$ of the desired interaction and the parameters of the 2d circuit, as well as the…

Quantum Physics · Physics 2023-02-07 Evgeny Mozgunov

Constructing ensembles of circuits which efficiently approximate the Haar measure over various groups is a long-standing and fundamental problem in quantum information theory. Recently it was shown that one can obtain approximate designs…

Quantum Physics · Physics 2025-06-23 Maxwell West , Diego García-Martín , N. L. Diaz , M. Cerezo , Martin Larocca

Unitary $t$-designs are the bread and butter of quantum information theory and beyond. An important issue in practice is that of efficiently constructing good approximations of such unitary $t$-designs. Building on results by Aubrun (Comm.…

Quantum Physics · Physics 2020-09-02 Cécilia Lancien , Christian Majenz

We show that the dynamics of generic quantum systems concentrate around their equilibrium value when measuring at arbitrary times. This means that the probability of finding them away from equilibrium is exponentially suppressed, with a…

Quantum Physics · Physics 2023-11-03 Jonathon Riddell , Nathan Pagliaroli , Álvaro M. Alhambra

We introduce magic-augmented Clifford circuits -- architectures in which Clifford circuits are preceded and/or followed by constant-depth circuits of non-Clifford (``magic") gates -- as a resource-efficient way to realize approximate…

Quantum Physics · Physics 2026-03-09 Yuzhen Zhang , Sagar Vijay , Yingfei Gu , Yimu Bao

Imperfect measurement can degrade a quantum error correction scheme. A solution that restores fault tolerance is to add redundancy to the process of syndrome extraction. In this work, we show how to optimize this process for an arbitrary…

Quantum Physics · Physics 2019-07-12 Vickram N. Premakumar , Hele Sha , Daniel Crow , Eric Bach , Robert Joynt

The anti-concentration phenomenon in probability theory has been intensively studied in recent years, with applications across many areas of mathematics. In most existing works, the ambient probability space is a product space generated by…

Combinatorics · Mathematics 2026-03-23 Viet H. Do , Hoi H. Nguyen , Kiet H. Phan , Tuan Tran , Van H. Vu

A set of high dimensional points $X=\{x_1, x_2,\ldots, x_n\} \subset R^d$ in isotropic position is said to be $\delta$-anti concentrated if for every direction $v$, the fraction of points in $X$ satisfying $|\langle x_i,v \rangle |\leq…

Data Structures and Algorithms · Computer Science 2024-10-29 Ainesh Bakshi , Pravesh Kothari , Goutham Rajendran , Madhur Tulsiani , Aravindan Vijayaraghavan

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

Universality of local unitary transformations is one of the cornerstones of quantum computing with many applications and implications that go beyond this field. However, it has been recently shown that this universality does not hold in the…

Quantum Physics · Physics 2024-05-17 Iman Marvian , Hanqing Liu , Austin Hulse

Efficient methods for the simulation of quantum circuits on classic computers are crucial for their analysis due to the exponential growth of the problem size with the number of qubits. Here we study lumping methods based on bisimulation,…

We prove anti-concentration results for polynomials of independent random variables with arbitrary degree. Our results extend the classical Littlewood-Offord result for linear polynomials, and improve several earlier estimates. We discuss…

Probability · Mathematics 2015-08-11 Raghu Meka , Oanh Nguyen , Van Vu

In this work, drawing inspiration from the type of noise present in real hardware, we study the output distribution of random quantum circuits under practical non-unital noise sources with constant noise rates. We show that even in the…

Quantum Physics · Physics 2023-06-30 Bill Fefferman , Soumik Ghosh , Michael Gullans , Kohdai Kuroiwa , Kunal Sharma

Entangled multipartite states are resources for universal quantum computation, but they can also give rise to ensembles of unitary transformations, a topic usually studied in the context of random quantum circuits. Using several graph state…

Quantum Physics · Physics 2016-05-25 Peter S. Turner , Damian Markham

Randomness is both a useful way to model natural systems and a useful tool for engineered systems, e.g. in computation, communication and control. Fully random transformations require exponential time for either classical or quantum…

Quantum Physics · Physics 2016-05-04 Fernando G. S. L. Brandao , Aram W. Harrow , Michal Horodecki

We study subleading corrections to the corner free energy in classical two-dimensional critical systems, focusing on a generic boundary perturbation by the stress-tensor of the underlying conformal field theory (CFT). In the particular case…

Statistical Mechanics · Physics 2013-12-17 Jean-Marie Stéphan , Jérôme Dubail

Quantum computers will need effective error-correcting codes. Current quantum processors require precise control of each particle, so having fewer particles to control might be beneficial. Although traditionally quantum computers are…

Quantum Physics · Physics 2021-10-25 Arun J. Moorthy , Lane G. Gunderman

We study the relationship between quantum chaos and pseudorandomness by developing probes of unitary design. A natural probe of randomness is the "frame potential," which is minimized by unitary $k$-designs and measures the $2$-norm…

Quantum Physics · Physics 2017-05-24 Daniel A. Roberts , Beni Yoshida

One of the key ingredients of many LOCC protocols in quantum information is a multiparticle (locally) maximally entangled quantum state, aka a critical state, that possesses local symmetries. We show how to design critical states with…

Quantum Physics · Physics 2021-05-04 Oskar Słowik , Adam Sawicki , Tomasz Maciążek