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Gauge theories are important descriptions for many physical phenomena and systems in quantum computation. Automorphism of gauge group naturally gives global symmetries of gauge theories. In this work we study such symmetries in gauge…

Strongly Correlated Electrons · Physics 2026-05-12 Po-Shen Hsin , Ryohei Kobayashi

Machine learning algorithms learn a desired input-output relation from examples in order to interpret new inputs. This is important for tasks such as image and speech recognition or strategy optimisation, with growing applications in the IT…

Quantum Physics · Physics 2015-05-27 M. Schuld , I. Sinayskiy , F. Petruccione

In continuous-variable quantum computation, identifying key elements that enable a quantum computational advantage is a long-standing issue. Starting from the standard results on the necessity of Wigner negativity, we develop a…

Quantum Physics · Physics 2025-03-12 Massimo Frigerio , Antoine Debray , Nicolas Treps , Mattia Walschaers

Free-fermionic states, also known as matchgates or Gaussian states, are a fundamental class of quantum states due to their efficient classical simulability and their crucial role across various domains of Physics. With the advent of quantum…

Quantum Physics · Physics 2025-03-26 Lennart Bittel , Antonio A. Mele , Jens Eisert , Lorenzo Leone

The problem of distinguishing two unitary transformations, or quantum gates, is analyzed and a function reflecting their statistical distinguishability is found. Given two unitary operations, $U_1$ and $U_2$, it is proved that there always…

Quantum Physics · Physics 2009-11-07 A. Acin

Quantum computing has emerged as a powerful tool for solving complex problems intractable for classical computers, particularly in popular fields such as cryptography, optimization, and neurocomputing. In this paper, we present a new…

Quantum Physics · Physics 2024-09-24 Xuan-Bac Nguyen , Hoang-Quan Nguyen , Hugh Churchill , Samee U. Khan , Khoa Luu

Quantum process tomography is an experimental technique to fully characterize an unknown quantum process. Standard quantum process tomography suffers from exponentially scaling of the number of measurements with the increasing system size.…

Quantum Physics · Physics 2022-08-02 Shichuan Xue , Yong Liu , Yang Wang , Pingyu Zhu , Chu Guo , Junjie Wu

We introduce a new family of quantum circuits for which the scrambling of a subspace of non-local operators is classically simulable. We call these circuits `super-Clifford circuits', since the Heisenberg time evolution of these operators…

Quantum Physics · Physics 2020-07-22 Mike Blake , Noah Linden

Many insights into the quantum world can be found by studying it from amongst more general operational theories of physics. In this thesis, we develop an approach to the study of such theories purely in terms of the behaviour of their…

Quantum Physics · Physics 2019-02-04 Sean Tull

In this paper we prove a collection of results on the structure of permutations in the Clifford Hierarchy. First, we leverage results from the cryptography literature on affine equivalence classes of 4-bit permutations which we use to find…

Quantum Physics · Physics 2025-08-05 Jonas T. Anderson , Andrew Connelly

In this note we prove a necessary set of conditions which must be satisfied by any controlled gate in the qubit Clifford Hierarchy. These conditions are straightforward to derive yet quite restricting. We also extend our proofs to gates…

Quantum Physics · Physics 2025-03-25 Jonas T. Anderson , Matthew Weippert

Schemes of classical shadows have been developed to facilitate the read-out of digital quantum devices, but similar tools for analog quantum simulators are scarce and experimentally impractical. In this work, we provide a measurement scheme…

Quantum Physics · Physics 2024-12-18 Janek Denzler , Antonio Anna Mele , Ellen Derbyshire , Tommaso Guaita , Jens Eisert

Simulation of quantum matters is a significant application of quantum computers. In contrast to the unitary operation which can be realized naturally on a quantum computer, the implementation of nonunitary operation, widely used in…

Quantum Physics · Physics 2021-12-21 Tong Liu , Jin-Guo Liu , Heng Fan

Unknown unitary inversion is a fundamental primitive in quantum computing and physics. Although recent work has demonstrated that quantum algorithms can invert arbitrary unknown unitaries without accessing their classical descriptions,…

Quantum Physics · Physics 2025-06-26 Yin Mo , Tengxiang Lin , Xin Wang

An obfuscator is an algorithm that translates circuits into functionally-equivalent similarly-sized circuits that are hard to understand. Efficient obfuscators would have many applications in cryptography. Until recently, theoretical…

Cryptography and Security · Computer Science 2017-10-11 Gorjan Alagic , Stacey Jeffery , Stephen P. Jordan

Quantum computations that involve only Clifford operations are classically simulable despite the fact that they generate highly entangled states; this is the content of the Gottesman-Knill theorem. Here we isolate the ingredients of the…

Quantum Physics · Physics 2007-05-23 Sean Clark , Richard Jozsa , Noah Linden

Gaussian processes (GP) are a widely used model for regression problems in supervised machine learning. Implementation of GP regression typically requires $O(n^3)$ logic gates. We show that the quantum linear systems algorithm [Harrow et…

Quantum Physics · Physics 2019-05-29 Zhikuan Zhao , Jack K. Fitzsimons , Joseph F. Fitzsimons

Quantum algorithms are sequences of abstract operations, performed on non-existent computers. They are in obvious need of categorical semantics. We present some steps in this direction, following earlier contributions of Abramsky, Coecke…

Quantum Physics · Physics 2016-11-09 Dusko Pavlovic

In this paper is shown an application of Clifford algebras to the construction of computationally universal sets of quantum gates for $n$-qubit systems. It is based on the well-known application of Lie algebras together with the especially…

Quantum Physics · Physics 2009-11-06 Alexander Yu. Vlasov

The Quantum Oracle Classification (QOC) problem is to classify a function, given only quantum black box access, into one of several classes without necessarily determining the entire function. Generally, QOC captures a very wide range of…

Computational Complexity · Computer Science 2015-10-29 Mark Zhandry