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Related papers: Unitary synthesis with fewer T gates

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How many T gates are needed to approximate an arbitrary $n$-qubit quantum state to within error $\varepsilon$? Improving prior work of Low, Kliuchnikov, and Schaeffer, we show that the optimal asymptotic scaling is…

Quantum Physics · Physics 2025-10-13 David Gosset , Robin Kothari , Kewen Wu

We study ancilla-free approximation of single-qubit unitaries $U\in {\rm SU}(2)$ by gate sequences over Clifford+$G$, where $G\in\{T,V\}$ or their generalization. Let $p$ denote the characteristic factor of the gate set (e.g., $p=2$ for…

Quantum Physics · Physics 2025-10-10 Kaoru Sano , Hayata Morisaki , Seiseki Akibue

Multiplication over binary fields is a crucial operation in quantum algorithms designed to solve the discrete logarithm problem for elliptic curve defined over $GF(2^n)$. In this paper, we present an algorithm for constructing quantum…

Quantum Physics · Physics 2025-01-28 Vivien Vandaele

We show how to directly and efficiently approximate arbitrary one-qubit unitaries, bypassing the Euler decomposition and the magnitude approximation problem, at the cost of one ancillary qubit. Our technique also applies to approximating…

Quantum Physics · Physics 2026-04-23 Vadym Kliuchnikov , Jendrik Brachter , Marcus P. da Silva

Our goal in this paper is to construct optimal topological generators for compact unitary Lie groups, extending the work of a letter of Sarnak and arXiv:1704.02106 on golden and super-golden gates to higher dimensions. To do so we consider…

Number Theory · Mathematics 2025-09-12 Rahul Dalal , Shai Evra , Ori Parzanchevski

We consider the problem of Clifford testing, which asks whether a black-box $n$-qubit unitary is a Clifford unitary or at least $\varepsilon$-far from every Clifford unitary. We give the first 4-query Clifford tester, which decides this…

Quantum Physics · Physics 2025-10-09 Marcel Hinsche , Zongbo Bao , Philippe van Dordrecht , Jens Eisert , Jop Briët , Jonas Helsen

Since quantum computing is currently in the NISQ-Era, compilation strategies to reduce the number of gates executed on specific hardware are required. In this work, we utilize the concept of synthesis of a data structure called Clifford…

Quantum Physics · Physics 2024-10-31 David Winderl , Qunsheng Huang , Arianne Meijer-van de Griend , Richie Yeung

We give a simple proof of a formula for the minimal time required to simulate a two-qubit unitary operation using a fixed two-qubit Hamiltonian together with fast local unitaries. We also note that a related lower bound holds for arbitrary…

Quantum Physics · Physics 2007-05-23 Andrew M. Childs , Henry L. Haselgrove , Michael A. Nielsen

Quantum algorithms may be described by sequences of unitary transformations called quantum gates and measurements applied to the quantum register of n quantum bits, qubits. A collection of quantum gates is called universal if it can be used…

Quantum Physics · Physics 2007-05-23 M. Mottonen , J. J. Vartiainen

Unitary synthesis is an optimization technique that can achieve optimal multi-qubit gate counts while mapping quantum circuits to restrictive qubit topologies. Because synthesis algorithms are limited in scalability by their exponentially…

Quantum Physics · Physics 2022-08-10 Mathias Weiden , Justin Kalloor , John Kubiatowicz , Ed Younis , Costin Iancu

We show that $n$-bit integers can be factorized by independently running a quantum circuit with $\tilde{O}(n^{3/2})$ gates for $\sqrt{n}+4$ times, and then using polynomial-time classical post-processing. The correctness of the algorithm…

Quantum Physics · Physics 2024-01-09 Oded Regev

We develop an angular momentum representation and implementation of the Clifford+T set of unitaries for qutrits. We show that local gates from this set can be realized by the sole use of suitable rotations and one-axis-twisting operations,…

Quantum Physics · Physics 2026-04-28 F. E. S. Steinhoff

Quantum gates executed on physical hardware are inevitably degraded by environmental noise. While state purification effectively distills static quantum resources, the dynamic execution of quantum algorithms requires a higher-order approach…

Quantum Physics · Physics 2026-04-02 Jiayi Zhao , Yu-Ao Chen , Guocheng Zhen , Chengkai Zhu , Ranyiliu Chen , Xin Wang

We propose a general method for preparing stabilizer states with reduced two-qubit gate count and depth compared to the state of the art. The method starts from a graph state representation of the stabilizer state and iteratively reduces…

The leading paradigm for performing computation on quantum memories can be encapsulated as distill-then-synthesize. Initially, one performs several rounds of distillation to create high-fidelity magic states that provide one good T gate, an…

Quantum Physics · Physics 2017-02-15 Earl T. Campbell , Mark Howard

State-of-the-art quantum circuit optimization (QCO) algorithms for T-count reduction often lead to a substantial increase in two-qubit gate count (2Q-count) -- a drawback that existing 2Q-count optimization techniques struggle to address…

Quantum Physics · Physics 2025-08-19 Mu-Te Lau , Hsiang-Chun Yang , Hsin-Yu Chen , Chung-Yang Ric Huang

As a cornerstone for many quantum linear algebraic and quantum machine learning algorithms, controlled quantum state preparation (CQSP) aims to provide the transformation of $|i\rangle |0^n\rangle \to |i\rangle |\psi_i\rangle $ for all…

Quantum Physics · Physics 2023-05-17 Pei Yuan , Shengyu Zhang

We show that it is possible to reduce the number of two-qubit gates needed for the construction of an arbitrary controlled-unitary transformation by up to two times using a tunable controlled-phase gate. On the platform of linear optics,…

Quantum Physics · Physics 2015-04-22 Karel Lemr , Karol Bartkiewicz , Antonín Černoch , Miloslav Dušek , Jan Soubusta

In this work we improve the runtime of recent classical algorithms for strong simulation of quantum circuits composed of Clifford and T gates. The improvement is obtained by establishing a new upper bound on the stabilizer rank of $m$…

Quantum Physics · Physics 2021-12-22 Hammam Qassim , Hakop Pashayan , David Gosset

The Unitary Synthesis Problem (Aaronson-Kuperberg 2007) asks whether any $n$-qubit unitary $U$ can be implemented by an efficient quantum algorithm $A$ augmented with an oracle that computes an arbitrary Boolean function $f$. In other…

Quantum Physics · Physics 2023-10-16 Alex Lombardi , Fermi Ma , John Wright