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Any technology requires precise benchmarking of its components, and the quantum technologies are no exception. Randomized benchmarking allows for the relatively resource economical estimation of the average gate fidelity of quantum gates…

Quantum Physics · Physics 2019-08-14 E. Onorati , A. H. Werner , J. Eisert

We present the generalization of the CNC formalism, based on closed and noncontextual sets of Pauli observables, to the setting of odd-prime-dimensional qudits. By introducing new CNC-type phase space point operators, we construct a…

Quantum Physics · Physics 2024-07-16 Michael Zurel , Arne Heimendahl

When the local dimension $d$ is an odd prime, the qudit Clifford group is only a 2-design, but not a 3-design, unlike the qubit counterpart. This distinction and its extension to Clifford orbits have profound implications for many…

Quantum Physics · Physics 2024-10-18 Huangjun Zhu , Chengsi Mao , Changhao Yi

Quantum measurements are slow, while classical processors are fast, yet existing hybrid protocols never exploit this asymmetry. In this work, we propose an alternative formulation of classical estimators as online algorithms that are…

Quantum Physics · Physics 2026-03-30 Marwa Marso , Sabrina Herbst , Jadwiga Wilkens , Vincenzo De Maio , Ivona Brandic , Richard Kueng

Quantum computing has potential to provide exponential speedups over classical computing for many important applications. However, today's quantum computers are in their early stages, and hardware quality issues hinder the scale of program…

We propose an efficient scheme for verifying quantum computations in the `high complexity' regime i.e. beyond the remit of classical computers. Previously proposed schemes remarkably provide confidence against arbitrarily malicious…

Quantum Physics · Physics 2017-05-24 Richard Jozsa , Sergii Strelchuk

We study measurements of the unitary generalization of Pauli operators. First, an analytical (constructive) solution to the eigenproblem of these operators is presented. Next, in the case of two subsystems, the Schmidt form of the…

Quantum Physics · Physics 2009-11-13 Tomasz Paterek

Quantifying quantum states' complexity is a key problem in various subfields of science, from quantum computing to black-hole physics. We prove a prominent conjecture by Brown and Susskind about how random quantum circuits' complexity…

We introduce a general framework for weak transversal gates -- probabilistic implementation of logical unitaries realized by local physical unitaries -- and propose a novel partially fault-tolerant quantum computing architecture that…

Quantum Physics · Physics 2025-10-10 Nobuyuki Yoshioka , Alireza Seif , Andrew Cross , Ali Javadi-Abhari

The following work presents a sufficiently general method for finding the parameters that characterise self-gravitating compact objects when their shadow contour is explicitly set. This method can be used in various algorithms to analyse…

General Relativity and Quantum Cosmology · Physics 2019-12-02 Vassil K. Tinchev

We present novel algorithms to estimate outcomes for qubit quantum circuits. Notably, these methods can simulate a Clifford circuit in linear time without ever writing down stabilizer states explicitly. These algorithms outperform previous…

Quantum Physics · Physics 2019-07-03 Patrick Rall , Daniel Liang , Jeremy Cook , William Kretschmer

We estimate the success probability of quantum protocols composed of Clifford operations in the presence of Pauli errors. Our method is derived from the fault-point formalism previously used to determine the success rate of low-distance…

Quantum Physics · Physics 2017-01-26 Smitha Janardan , Yu Tomita , Mauricio Gutierrez , Kenneth R. Brown

Scrambling of quantum information is an important feature at the root of randomization and benchmarking protocols, the onset of quantum chaos, and black-hole physics. Unscrambling this information is possible given perfect knowledge of the…

Quantum Physics · Physics 2024-03-06 Lorenzo Leone , Salvatore F. E. Oliviero , Seth Lloyd , Alioscia Hamma

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

The computation of \(\operatorname{tr}(AB)\) is essential in quantum science and artificial intelligence, yet classical methods for \( d \)-dimensional matrices \( A \) and \( B \) require \( O(d^2) \) complexity, which becomes infeasible…

Quantum Physics · Physics 2025-10-31 Yu Wang

For qubits, Monte Carlo estimation of the average fidelity of Clifford unitaries is efficient -- it requires a number of experiments that is independent of the number $n$ of qubits and classical computational resources that scale only…

Quantum Physics · Physics 2014-10-23 Giulia Gualdi , David Licht , Daniel M. Reich , Christiane P. Koch

Calculating the properties of Gibbs states is an important task in Quantum Chemistry and Quantum Machine Learning. Previous work has proposed a quantum algorithm which predicts Gibbs state expectation values for $M$ observables from only…

Quantum Physics · Physics 2024-09-10 Arnav Sharma , Kevin Obenland

Many quantum information protocols require the implementation of random unitaries. Because it takes exponential resources to produce Haar-random unitaries drawn from the full $n$-qubit group, one often resorts to $t$-designs. Unitary…

As quantum devices progress towards a quantum advantage regime, they become harder to benchmark. A particularly relevant challenge is to assess the quality of the whole computation, beyond testing the performance of each single operation.…

Quantum Physics · Physics 2026-04-03 Flavio Baccari , Pavel Kos , Georgios Styliaris

Quantum circuits are considered more powerful than classical circuits and require exponential resources to simulate classically. Clifford circuits are a special class of quantum circuits that can be simulated in polynomial time but still…

Quantum Physics · Physics 2025-12-09 Yuchen Pang , Edgar Solomonik