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We present a method to conduct both quantum state reconstruction and entanglement purification simultaneously that is advantageous in several respects over previous work in this direction, showing that the number of Bell pairs necessary to…

Quantum Physics · Physics 2026-02-23 Takafumi Oka , Michal Hajdušek , Shota Nagayama , Rodney Van Meter

In this paper, we propose a protocol for complete Bell-state analysis for two superconducting-quantum-interference-device qubits. The Bell-state analysis could be completed by using a sequence of microwave pulses designed by the transition-…

Quantum Physics · Physics 2017-09-13 Yi-Hao Kang , Ye-Hong Chen , Zhi-Cheng Shi , Bi-Hua Huang , Jie Song , Yan Xia

We show that thresholds for fault-tolerant quantum computation are solely determined by the quality of single-system operations if one allows for d-dimensional systems with $8 \leq d \leq 32$. Each system serves to store one logical qubit…

Quantum Physics · Physics 2016-08-16 W. Dür , H. -J. Briegel

The stabilization of a quantum computer by repeated error correction can be reduced almost entirely to repeated preparation of blocks of qubits in quantum codeword states. These are multi-particle entangled states with a high degree of…

Quantum Physics · Physics 2007-05-23 Andrew M. Steane

Benchmarking the performance of quantum error correction codes in physical systems is crucial for achieving fault-tolerant quantum computing. Current methodologies, such as (shadow) tomography or direct fidelity estimation, fall short in…

Quantum Physics · Physics 2024-10-17 Junjie Chen , Pei Zeng , Qi Zhao , Xiongfeng Ma , You Zhou

Can one certify the preparation of a coherent, many-body quantum state by measurements with bounded accuracy in the presence of noise and decoherence? Here, we introduce a criterion to assess the fragility of large-scale quantum states…

Quantum Physics · Physics 2013-11-15 Florian Fröwis , Maarten van den Nest , Wolfgang Dür

We analyze the use of photonic links to enable large-scale fault-tolerant connectivity of locally error-corrected modules based on neutral atom arrays. Our approach makes use of recent theoretical results showing the robustness of surface…

This study explores the feasibility of utilizing quantum error correction (QEC) to generate and store logical Bell states in heralded quantum entanglement protocols, crucial for quantum repeater networks. Two lattice surgery-based protocols…

Quantum Physics · Physics 2025-08-12 Vladlen Galetsky , Nilesh Vyas , Alberto Comin , Janis Nötzel

We study active steering protocols for weakly measured qubits in the presence of error channels due to amplitude and phase noise. If the error rate is sufficiently small, the protocol approaches and stabilizes a predesignated pure target…

Quantum Physics · Physics 2025-01-23 Nico Ackermann , Samuel Morales , Alfredo Levy Yeyati , Sebastian Diehl , Reinhold Egger

Recent progress in quantum information has led to the start of several large national and industrial efforts to build a quantum computer. Researchers are now working to overcome many scientific and technological challenges. The program's…

Quantum Physics · Physics 2015-10-07 John M. Martinis

Integrated quantum photonic circuits are becoming increasingly complex. Accurate calibration of device parameters and detailed characterization of the prepared quantum states are critically important for future progress. Here we report on…

Quantum Physics · Physics 2013-06-17 H. W. Li , J. Wabnig , D. Bitauld , P. Shadbolt , A. Politi , A. Laing , J. L. O'Brien , A. O. Niskanen

The class of two-qubit Bell-diagonal states has been the workhorse for developing understanding about the geometry, dynamics, and applications of quantum resources. In this article, we present a quantum circuit for preparing Bell-diagonal…

Quantum Physics · Physics 2019-04-02 Mauro B. Pozzobom , Jonas Maziero

We present a technique that dramatically improves the accuracy of adiabatic state transfer for a broad class of realistic Hamiltonians. For some systems, the total error scaling can be quadratically reduced at a fixed maximum transfer rate.…

Quantum Physics · Physics 2012-01-17 Nathan Wiebe , Nathan S. Babcock

The noise in physical qubits is fundamentally asymmetric: in most devices, phase errors are much more probable than bit flips. We propose a quantum error correcting code which takes advantage of this asymmetry and shows good performance at…

Quantum Physics · Physics 2015-06-26 Lev Ioffe , Marc Mezard

Quantum gates in topological quantum computation are performed by braiding non-Abelian anyons. These braiding processes can presumably be performed with very low error rates. However, to make a topological quantum computation architecture…

Quantum Physics · Physics 2016-04-22 Adrian Hutter , James R. Wootton

A procedure is developed to automatically correct the bit flip and the arbitrary phase change errors in Generalized Bell states (GBS). The phase and parity characteristics of the GBS are encoded in ancilla bits without altering the state…

Quantum Physics · Physics 2010-10-12 Pratyush Pandey , Sriram Prasath E. , Manu Gupta , Prasanta K. Panigrahi

Secure quantum networks are a bedrock requirement for developing a future quantum internet. However, quantum channels are susceptible to channel noise that introduce errors in the transmitted data. The traditional approach to providing…

Quantum Physics · Physics 2025-05-30 Nitin Jha , Abhishek Parakh , Mahadevan Subramaniam

Quantum state purification, a process that aims to recover a state closer to a system's principal eigenstate from multiple copies of an unknown noisy quantum state, is crucial for restoring noisy states to a more useful form in quantum…

Quantum Physics · Physics 2025-09-25 Keming He , Chengkai Zhu , Hongshun Yao , Jinguo Liu , Yinan Li , Xin Wang

A multipartite quantum state violates a Bell inequality asymptotically if, after jointly processing by general local operations an arbitrarily large number of copies of it, the result violates the inequality. In the bipartite case we show…

Quantum Physics · Physics 2009-11-11 Ll. Masanes

We investigate the problem of bounding the quantum process fidelity given bounds on the fidelities between target states and the action of a process on a set of pure input states. We formulate the problem as a semidefinite program and prove…

Quantum Physics · Physics 2018-11-28 Karl Mayer , Emanuel Knill