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Related papers: Completeness of the ZX-calculus

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The Gottesman-Knill theorem asserts that a quantum circuit composed of Clifford gates can be efficiently simulated on a classical computer. Here we revisit this theorem and extend it to quantum circuits composed of Clifford and T gates,…

Quantum Physics · Physics 2019-04-11 Sergey Bravyi , David Gosset

We apply the cutting stabiliser decomposition techniques [arXiv:2403.10964] to the quantum states generated from magic state cultivation [arXiv:2409.17595], post-selected upon all $+1$ measured values for simplicity. The resultant states to…

Quantum Physics · Physics 2025-09-23 Kwok Ho Wan , Zhenghao Zhong

In this paper, we give a modified version of the qutrit ZX-calculus, by which we represent qutrit graph states as diagrams and prove that the qutrit version of local complementation property is true if and only if the qutrit Hadamard gate…

Quantum Physics · Physics 2017-04-21 Xiaoyan Gong , Quanlong Wang

In this paper we exploit the utility of the triangle symbol which has a complicated expression in terms of spider diagrams in ZX-calculus, and its role within the ZX-representation of AND-gates in particular. First, we derive spider nest…

Quantum Physics · Physics 2021-09-07 Anthony Munson , Bob Coecke , Quanlong Wang

We introduce group surface codes, which are a natural generalization of the $\mathbb{Z}_2$ surface code, and equivalent to quantum double models of finite groups with specific boundary conditions. We show that group surface codes can be…

Quantum Physics · Physics 2026-03-06 Naren Manjunath , Vieri Mattei , Apoorv Tiwari , Tyler D. Ellison

Parametrised quantum circuits contain phase gates whose phase is determined by a classical algorithm prior to running the circuit on a quantum device. Such circuits are used in variational algorithms like QAOA and VQE. In order for these…

Quantum Physics · Physics 2025-08-27 John van de Wetering , Richie Yeung , Tuomas Laakkonen , Aleks Kissinger

Simulating physical systems on near-term quantum computers often requires preparing states within constrained subspaces, like those with fixed particle number or spin. We use Lie algebraic techniques to prove that hardware-efficient gates…

Quantum Physics · Physics 2026-05-05 Andreas Stergiou , Nicolas PD Sawaya

We introduce the first complete equational theory for quantum circuits. More precisely, we introduce a set of circuit equations that we prove to be sound and complete: two circuits represent the same unitary map if and only if they can be…

Quantum Physics · Physics 2023-11-15 Alexandre Clément , Nicolas Heurtel , Shane Mansfield , Simon Perdrix , Benoît Valiron

Prevailing proposals for the first generation of quantum computers make use of 2-level systems, or qubits, as the fundamental unit of quantum information. However, recent innovations in quantum error correction and magic state distillation…

Quantum Physics · Physics 2019-02-18 Luke E. Heyfron , Earl Campbell

A major challenge for scaling up superconducting quantum computers is unwanted couplings between qubits, which lead to always-on ZZ couplings that impact gate fidelities by shifting energy levels conditional on qubit states. To tackle this…

Quantum Physics · Physics 2024-12-30 Simon Pettersson Fors , Jorge Fernández-Pendás , Anton Frisk Kockum

The Scalable ZX-calculus is a compact graphical language used to reason about linear maps between quantum states. These diagrams have multiple applications, but they frequently have to be constructed in a case-by-case basis. In this work we…

Quantum Physics · Physics 2023-11-17 Augustin Borgna , Rafael Romero

We introduce a dichromatic calculus (RG) for qutrit systems. We show that the decomposition of the qutrit Hadamard gate is non-unique and not derivable from the dichromatic calculus. As an application of the dichromatic calculus, we depict…

Quantum Physics · Physics 2014-12-31 Quanlong Wang , Xiaoning Bian

The field of quantum machine learning (QML) explores how quantum computers can be used to more efficiently solve machine learning problems. As an application of hybrid quantum-classical algorithms, it promises a potential quantum advantages…

Quantum Physics · Physics 2022-10-24 Mark Koch

Quantum information science strives to leverage the quantum-mechanical nature of our universe in order to achieve large improvements in certain information processing tasks. In deep-space optical communications, current receivers for the…

Quantum Physics · Physics 2020-04-16 Narayanan Rengaswamy

We start by studying the subgroup structures underlying stabilizer circuits and we use our results to propose a new normal form for stabilizer circuits. This normal form is computed by induction using simple conjugation rules in the…

Quantum Physics · Physics 2021-07-05 Marc Bataille

This paper has two tightly intertwined aims: (i) To introduce an intuitive and universal graphical calculus for multi-qubit systems, the ZX-calculus, which greatly simplifies derivations in the area of quantum computation and information.…

Quantum Physics · Physics 2015-03-13 Bob Coecke , Ross Duncan

Finite group extensions offer a natural language to quantum computing. In a nutshell, one roughly describes the action of a quantum computer as consisting of two finite groups of gates: error gates from the general Pauli group P and…

Quantum Physics · Physics 2008-12-18 Michel Planat , Philippe Jorrand

We present a simple and efficient way to reduce the contraction cost of a tensor network to simulate a quantum circuit. We start by interpreting the circuit as a ZX-diagram. We then use simplification and local complementation rules to…

Quantum Physics · Physics 2023-05-05 Tristan Cam , Simon Martiel

Verifying equivalence between two quantum circuits is a hard problem, that is nonetheless crucial in compiling and optimizing quantum algorithms for real-world devices. This paper gives a Turing reduction of the (universal) quantum circuits…

Quantum Physics · Physics 2024-03-28 Jingyi Mei , Tim Coopmans , Marcello Bonsangue , Alfons Laarman

An efficient technique of computing on encrypted data allows a client with limited capability to perform complex operations on a remote fault-tolerant server without leaking anything about the input or output. Quantum computing provides…

Quantum Physics · Physics 2025-09-25 Mohit Joshi , Manoj Kumar Mishra , S. Karthikeyan