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Clifford group lies at the core of quantum computation -- it underlies quantum error correction, its elements can be used to perform magic state distillation and they form randomized benchmarking protocols, Clifford group is used to study…

Quantum Physics · Physics 2022-08-26 Sergey Bravyi , Joseph A. Latone , Dmitri Maslov

Creation and manipulation of entanglement with low error is essential in quantum information systems. In practice, two-qubit entangling gates constitute a dominant error source, limiting circuit depths and performance in fault-tolerant…

We propose a practical, scalable, and efficient scheme for quantum computation using spatially separated matter qubits and single photon interference effects. The qubit systems can be NV-centers in diamond, Pauli-blockade quantum dots with…

Quantum Physics · Physics 2009-11-10 Sean D. Barrett , Pieter Kok

We present and experimentally implement a real-time protocol for calibrating the frequency of a resonantly driven qubit, achieving exponential scaling in calibration precision with the number of measurements, up to the limit imposed by…

We construct a polynomial-time classical algorithm that samples from the output distribution of noisy geometrically local Clifford circuits with any product-state input and single-qubit measurements in any basis. Our results apply to…

Quantum Physics · Physics 2026-01-09 Jon Nelson , Joel Rajakumar , Dominik Hangleiter , Michael J. Gullans

Recent work (Nathan et al, arXiv:2405.05671) proposed an architecture for a dissipatively stabilized GKP qubit, and protocols for protected Clifford gates. Here we propose a protocol for a protected non-Clifford $\sqrt{T}$ gate at the…

Quantum Physics · Physics 2025-07-29 Liam O'Brien , Gil Refael , Frederik Nathan

The central challenge of quantum computing is implementing high-fidelity quantum gates at scale. However, many existing approaches to qubit control suffer from a scale-performance trade-off, impeding progress towards the creation of useful…

Gate fidelity -- an average fidelity over all possible input states -- is the workhorse metric for benchmarking quantum gates or circuits, yet fault-tolerant quantum computing ultimately depends on the worst-case behavior, typically…

Quantum Physics · Physics 2026-03-10 Kyoungho Cho , Ilkwon Sohn , Yongsoo Hwang , Jeongho Bang

As quantum circuits become more integrated and complex, additional error sources that were previously insignificant start to emerge. Consequently, the fidelity of quantum gates benchmarked under pristine conditions falls short of predicting…

Protocols for discriminating between a pair of channels or for estimating a channel parameter can often be aided by adaptivity or by entanglement between the probe states. This can make it difficult to bound the best possible performance…

Quantum Physics · Physics 2021-10-07 Jason L. Pereira , Leonardo Banchi , Stefano Pirandola

As quantum systems expand in size and complexity, manual qubit characterization and gate optimization will be a non-scalable and time-consuming venture. Physical qubits have to be carefully calibrated because quantum processors are very…

Quantum Physics · Physics 2022-05-26 Peng Qian , Shahid Qamar , Xiao Xiao , Yanwu Gu , Xudan Chai , Zhen Zhao , Nicolo Forcellini , Dong E. Liu

We report the first complete characterization of single-qubit and two-qubit gate fidelities in silicon-based spin qubits, including cross-talk and error correlations between the two qubits. To do so, we use a combination of standard…

Spin systems controlled and probed by magnetic resonance have been valuable for testing the ideas of quantum control and quantum error correction. This paper introduces an X-band pulsed electron spin resonance spectrometer designed for…

Quantum Physics · Physics 2016-05-25 Daniel K. Park , Guanru Feng , Robabeh Rahimi , Jonathan Baugh , Raymond Laflamme

An important step in building a quantum computer is calibrating experimentally implemented quantum gates to produce operations that are close to ideal unitaries. The calibration step involves estimating the systematic errors in gates and…

Quantum Physics · Physics 2021-10-22 Shelby Kimmel , Guang Hao Low , Theodore J. Yoder

A practical implementation of a quantum computer requires robust qubits that are protected against their noisy environment. Dynamical decoupling techniques have been successfully used in the past to offer protected high-fidelity gate…

Fault-tolerant quantum computing hinges on efficient logical compilation, in particular, translating high-level circuits into code-compatible implementations. Gate-by-gate compilation often yields deep circuits, requiring significant…

Quantum Physics · Physics 2026-02-16 Alexander Popov , Nico Meyer , Daniel D. Scherer , Guido Dietl

The fidelity of entangling operations is a key figure of merit in quantum information processing, especially in the context of quantum error correction. High-fidelity entangling gates in neutral atoms have seen remarkable advancement…

Quantum Physics · Physics 2025-02-21 Richard Bing-Shiun Tsai , Xiangkai Sun , Adam L. Shaw , Ran Finkelstein , Manuel Endres

We introduce a framework for the formal specification and verification of quantum circuits based on the Feynman path integral. Our formalism, built around exponential sums of polynomial functions, provides a structured and natural way of…

Quantum Physics · Physics 2019-01-30 Matthew Amy

We describe and expand upon the scalable randomized benchmarking protocol proposed in Phys. Rev. Lett. 106, 180504 (2011) which provides a method for benchmarking quantum gates and estimating the gate-dependence of the noise. The protocol…

Quantum Physics · Physics 2012-04-30 Easwar Magesan , Jay M. Gambetta , Joseph Emerson