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The performance of quantum error correction can be significantly improved if detailed information about the noise is available, allowing to optimize both codes and decoders. It has been proposed to estimate error rates from the syndrome…

Quantum Physics · Physics 2022-09-21 Thomas Wagner , Hermann Kampermann , Dagmar Bruß , Martin Kliesch

The preparation of a quantum state using a noisy quantum computer (gate noise strength $\delta$), will necessarily affect an O($\delta$)-fraction of the qubits, no matter which protocol is used. Here, we show that fault-tolerant quantum…

Quantum Physics · Physics 2026-02-20 Matthias Christandl , Omar Fawzi , Ashutosh Goswami

The highest information rate at which quantum error-correction schemes work reliably on a channel, which is called the quantum capacity, is proven to be lower bounded by the limit of the quantity termed coherent information maximized over…

Quantum Physics · Physics 2007-05-23 Mitsuru Hamada

This paper proves the threshold result, which asserts that quantum computation can be made robust against errors and inaccuracies, when the error rate, $\eta$, is smaller than a constant threshold, $\eta_c$. The result holds for a very…

Quantum Physics · Physics 2007-05-23 Dorit Aharonov , Michael Ben-Or

In this paper we estimate the fidelity of stabilizer and CSS codes. First, we derive a lower bound on the fidelity of a stabilizer code via its quantum enumerator. Next, we find the average quantum enumerators of the ensembles of finite…

Quantum Physics · Physics 2017-02-10 Alexei Ashikhmin

We address the task of verifying whether a quantum computer, designed to be protected by a specific stabilizer code, correctly encodes the corresponding logical qubits. To achieve this, we develop a general framework for subspace…

Quantum Physics · Physics 2024-12-10 Congcong Zheng , Xutao Yu , Zaichen Zhang , Ping Xu , Kun Wang

Orthogonal geometric constructions are the basis of many many quantum error-correcting codes (QEC), but strict orthogonality constraints limit design flexibility and resource efficiency. We introduce a quasi-orthogonal geometric framework…

We show that quantum circuits cannot be made fault-tolerant against a depolarizing noise level of approximately 45%, thereby improving on a previous bound of 50% (due to Razborov). Our precise quantum circuit model enables perfect gates…

Quantum Physics · Physics 2007-05-23 Harry Buhrman , Richard Cleve , Monique Laurent , Noah Linden , Alexander Schrijver , Falk Unger

We propose a quantum-state-certification protocol for stabilizer states, motivated by application in in-situ testing of NISQ-era quantum computer systems: The number of qubits is bounded, and in terms of cost of running the protocol,…

Quantum Physics · Physics 2025-07-21 Dirk Oliver Theis

This paper aims to give an overview of the current state of fault-tolerant quantum computing, by surveying a number of results in the field. We show that thresholds can be obtained for a simple noise model as first proved in [AB97, Kit97,…

Quantum Physics · Physics 2011-11-08 Daan Staudt

The compass model on a square lattice provides a natural template for building subsystem stabilizer codes. The surface code and the Bacon-Shor code represent two extremes of possible codes depending on how many gauge qubits are fixed. We…

Quantum Physics · Physics 2019-06-05 Muyuan Li , Daniel Miller , Michael Newman , Yukai Wu , Kenneth R. Brown

Typical stabilizer codes aim to solve the general problem of fault-tolerance without regard for the structure of a specific system. By incorporating a broader representation-theoretic perspective, we provide a generalized framework that…

Quantum Physics · Physics 2026-03-30 Zachary P. Bradshaw , Margarite L. LaBorde , Dillon Montero

We extend a low-rate improvement of the random coding bound on the reliability of a classical discrete memoryless channel to its quantum counterpart. The key observation that we make is that the problem of bounding below the error exponent…

Quantum Physics · Physics 2007-05-23 Alexander Barg

A novel scheme is presented for fault-tolerant quantum computation based on the cluster model. Some relevant logical cluster states are constructed in concatenation by post-selection through verification, without necessity of recovery…

Quantum Physics · Physics 2010-08-24 Keisuke Fujii , Katsuji Yamamoto

An important outstanding challenge that must be overcome in order to fully utilize the XY surface code for correcting biased Pauli noise is the phenomena of fragile temporal boundaries that arise during the standard logical state…

Quantum Physics · Physics 2024-08-16 Pei-Kai Tsai , Yue Wu , Shruti Puri

Collective coherent (CC) errors are inevitable, as every physical qubit undergoes free evolution under its kinetic Hamiltonian. These errors can be more damaging than stochastic Pauli errors because they affect all qubits coherently,…

Quantum Physics · Physics 2025-11-14 En-Jui Chang

We consider realistic, multi-parameter error models and investigate the performance of the surface code for three possible fault-tolerant superconducting quantum computer architectures. We map amplitude and phase damping to a diagonal Pauli…

Quantum Physics · Physics 2012-12-21 Joydip Ghosh , Austin G. Fowler , Michael R. Geller

I discuss how to perform fault-tolerant quantum computation with concatenated codes using local gates in small numbers of dimensions. I show that a threshold result still exists in three, two, or one dimensions when next-to-nearest-neighbor…

Quantum Physics · Physics 2015-06-26 Daniel Gottesman

Quantum computers have the potential to change the way we solve computational problems. Due to the noisy nature of qubits, the need arises to correct physical errors occurring during computation. The surface code is a promising candidate…

Quantum Physics · Physics 2024-05-06 Gyorgy P. Geher , Ophelia Crawford , Earl T. Campbell

Fault-tolerant quantum computing based on surface codes has emerged as a popular route to large-scale quantum computers capable of accurate computation even in the presence of noise. Its popularity is, in part, because the fault-tolerance…

Quantum Physics · Physics 2022-07-04 Jing Hao Chai , Hui Khoon Ng