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Related papers: Learning quantum circuits of some $T$ gates

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We present an algorithm for efficiently approximating of qubit unitaries over gate sets derived from totally definite quaternion algebras. It achieves $\varepsilon$-approximations using circuits of length $O(\log(1/\varepsilon))$, which is…

Quantum Physics · Physics 2015-10-16 Vadym Kliuchnikov , Alex Bocharov , Martin Roetteler , Jon Yard

Demonstrating quantum advantage in machine learning tasks requires navigating a complex landscape of proposed models and algorithms. To bring clarity to this search, we introduce a framework that connects the structure of parametrized…

Quantum Physics · Physics 2025-12-23 Sergi Masot-Llima , Elies Gil-Fuster , Carlos Bravo-Prieto , Jens Eisert , Tommaso Guaita

Measuring global quantum properties-such as the fidelity to complex multipartite states-is both an essential and experimentally challenging task. Classical shadow estimation offers favorable sample complexity, but typically relies on…

Quantum Physics · Physics 2026-02-11 Qingyue Zhang , Dayue Qin , Zhou You , Feng Xu , Jens Eisert , You Zhou

The ability to efficiently simulate random quantum circuits using a classical computer is increasingly important for developing Noisy Intermediate-Scale Quantum devices. Here we present a tensor network states based algorithm specifically…

Quantum Physics · Physics 2021-02-24 Chu Guo , Youwei Zhao , He-Liang Huang

We initiate the study of parameterized complexity of $\textsf{QMA}$ problems in terms of the number of non-Clifford gates in the problem description. We show that for the problem of parameterized quantum circuit satisfiability, there exists…

Quantum Physics · Physics 2023-07-13 Srinivasan Arunachalam , Sergey Bravyi , Chinmay Nirkhe , Bryan O'Gorman

This work presents a precise connection between Clifford circuits, Shor's factoring algorithm and several other famous quantum algorithms with exponential quantum speed-ups for solving Abelian hidden subgroup problems. We show that all…

Quantum Physics · Physics 2014-09-18 Juan Bermejo-Vega , Cedric Yen-Yu Lin , Maarten Van den Nest

In this paper we treat a cavity QED quantum computation. Namely, we consider a model of quantum computation based on n atoms of laser-cooled and trapped linearly in a cavity and realize it as the n atoms Tavis-Cummings Hamiltonian…

Quantum Physics · Physics 2007-07-02 Kazuyuki Fujii , Kyoko Higashida , Ryosuke Kato , Yukako Wada

Random quantum states have various applications in quantum information science. We discover a new ensemble of quantum states that serve as an $\epsilon$-approximate state $t$-design while possessing extremely low entanglement, magic, and…

Quantum Physics · Physics 2025-12-25 Wonjun Lee , Minki Hhan , Gil Young Cho , Hyukjoon Kwon

The treewidth of a graph is a useful combinatorial measure of how close the graph is to a tree. We prove that a quantum circuit with $T$ gates whose underlying graph has treewidth $d$ can be simulated deterministically in…

Quantum Physics · Physics 2009-07-12 Igor L. Markov , Yaoyun Shi

The Clifford group is a finite subgroup of the unitary group generated by the Hadamard, the CNOT, and the Phase gates. This group plays a prominent role in quantum error correction, randomized benchmarking protocols, and the study of…

Quantum Physics · Physics 2021-11-17 Sergey Bravyi , Ruslan Shaydulin , Shaohan Hu , Dmitri Maslov

Identifying the symmetry properties of quantum states is a central theme in quantum information theory and quantum many-body physics. In this work, we investigate quantum learning problems in which the goal is to identify a hidden symmetry…

Quantum Physics · Physics 2026-05-28 Marcel Hinsche , Jens Eisert , Jose Carrasco

The Clifford group is the set of gates generated by controlled-Z gates, the phase gate and the Hadamard gate. We will say that a n-qubit state is a Clifford state if it can be prepared using Clifford gates. These states are known as the…

Quantum Physics · Physics 2023-08-03 Frederic Latour , Oscar Perdomo

For random quantum circuits on $n$ qubits of depth $\Theta(\log n)$ with depolarizing noise, the task of sampling from the output state can be efficiently performed classically using a Pauli path method [Aharonov et al. Proceedings of the…

Quantum Physics · Physics 2025-05-07 Guillermo González-García , J. Ignacio Cirac , Rahul Trivedi

In quantum computing the decoherence time of the qubits determines the computation time available and this time is very limited when using current hardware. In this paper we minimize the execution time (the depth) for a class of circuits…

An $n$-qubit quantum circuit is said to be peaked if it has an output probability that is at least inverse-polynomially large as a function of $n$. We describe a classical algorithm with quasipolynomial runtime $n^{O(\log{n})}$ that…

Quantum Physics · Physics 2023-09-18 Sergey Bravyi , David Gosset , Yinchen Liu

We show that states obtained from deep random Clifford circuits doped with non-Clifford phase gates (including T-gates and $\sqrt{\mathrm{T}}$-gates) can be disentangled completely, provided the number of non-Clifford gates is smaller or…

Quantum Physics · Physics 2026-01-08 Gerald E. Fux , Benjamin Béri , Rosario Fazio , Emanuele Tirrito

Simulating Clifford and near-Clifford circuits using the extended stabilizer formalism has become increasingly popular, particularly in quantum error correction. Compared to the state-vector approach, the extended stabilizer formalism can…

Quantum Physics · Physics 2026-05-18 Vu Tuan Hai , Bui Cao Doanh , Le Vu Trung Duong , Pham Hoai Luan , Yasuhiko Nakashima

Randomized benchmarking is a technique for estimating the average fidelity of a set of quantum gates. For general gatesets, however, it is difficult to draw robust conclusions from the resulting data. Here we propose a new method based on…

Quantum Physics · Physics 2019-07-31 Jonas Helsen , Xiao Xue , Lieven M. K. Vandersypen , Stephanie Wehner

Anticoncentration describes how an ensemble of quantum states spreads over the allowed Hilbert space, leading to statistically uniform output probability distributions. In this work, we investigate the anticoncentration of random Clifford…

Quantum Physics · Physics 2025-10-14 Beatrice Magni , Alexios Christopoulos , Andrea De Luca , Xhek Turkeshi

Using the tensor product representation in the density matrix renormalization group, we show that a quantum circuit of Grover's algorithm, which has one-qubit unitary gates, generalized Toffoli gates, and projective measurements, can be…

Quantum Physics · Physics 2007-05-23 A. Kawaguchi , K. Shimizu , Y. Tokura , N. Imoto
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