Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:quant-ph/9812085

Measuring the entangled Bell and GHZ aspects using a single-qubit shuttle

Ulf Larsen

Published Dec 30, 1998• 1 citation
arXivHTMLPDF

Abstract

A complete, non-demolition procedure is established for measuring multi-qubit entangled states, such as the Bell-states and the GHZ-states, which is essential in certain processes of quantum communication, computation, and teleportation. No interaction between the individual parts of the entangled system, nor with any environment is required. A small probe (e.g. a single qubit) takes care of all interaction with the system, and is used repeatedly. The probe-qubit interaction is of the simplest form, and only this one type of interaction is required to perform a complete measurement. The process may be divided into elementary local operations and interactions, taking place sequentially as the probe visits each of the qubits. A shuttle mode is described, which may be repeated indefinitely. By the quantum Zeno effect, the entangled states can be maintained until released in a predictable state. This shuttle process is stable, and self-correcting, by virtue of the standard measurements performed repeatedly on the probe.

DOI
10.48550/arxiv.quant-ph/9812085

Related papers

Local measurement for a set of n -qubit maximally entangled states in cavity QED

Chui‐Ping Yang, Siyuan Han

An approach for performing a local measurement on a set of complete $n$-qubit maximally entangled states via cavity QED is presented. The method operates essentially by creating a single photon in the cavity through one qubit and then performing a joint multiqubit phase shift on the remaining qubits with the assistance of the photon. It is shown that for three-level qubit systems, a complete set of ${2}^{n}$ $n$-qubit maximally entangled states can be measured simultaneously, deterministic and independent of the number of qubits. Hence, the method is very efficient for realizing multiqubit GHZ-state measurement which is important to quantum information processing and communication.

Physical Review A•May 14, 2007•6 citations

GHZ transform (I): Bell transform and quantum teleportation

Yong Zhang, Kun Zhang

It is well-known that maximally entangled states such as the Greenberger-Horne-Zeilinger (GHZ) states, with the Bell states as the simplest examples, are widely exploited in quantum information and computation. We study the application of such maximally entangled states from the viewpoint of the GHZ transform, which is a unitary basis transformation from the product states to the GHZ states. The algebraic structure of the GHZ transform is made clear and representative examples for it are verified as multi-qubit Clifford gates. In this paper, we focus on the Bell transform as the simplest example of the GHZ transform and apply it to the reformulation of quantum circuit model of teleportation and the reformulation of the fault-tolerant construction of single-qubit gates and two-qubit gates in teleportation-based quantum computation. We clearly show that there exists a natural algebraic structure called the teleportation operator in terms of the Bell transform to catch essential points of quantum teleportation, and hence we expect that there would also exist interesting algebraic structures in terms of the GHZ transform to play important roles in quantum information and computation.

arXiv:1401.7009•Jan 27, 2014•1 citation

Weight-four parity checks with silicon spin qubits

Brennan Undseth, Nicola Meggiato, Yi-Hsien Wu +7 more

Recent advances in coherent spin shuttling have made sparse semiconductor spin qubit arrays an appealing solid-state platform to realize quantum processors. The dynamic and long-range connectivity enabled by shuttling is also essential for many quantum error-correction (QEC) schemes. Here, we demonstrate a silicon spin-qubit device that comprises a shuttling bus for coherently transporting qubits that can interact at four isolated locations we call bus stops. We dynamically populate the array and tune all single- and two-qubit operations using shuttling and quantum non-demolition (QND) spin measurements, without access to charge sensing in most of the device. We achieve universal control of the effective five-qubit processor and select the connectivity required to form a surface-code stabilizer plaquette that supports X- and Z-type parity checks up to weight-four. We use the parity checks to generate multi-qubit entanglement between all qubit combinations in the array and report the genuine entanglement of a five-qubit Greenberger-Horne-Zeilinger (GHZ) state, constituting the largest such state ever constructed with gate-defined semiconductor spins. This work opens immediate opportunities to pursue QEC experiments with spin qubits, and the protocols developed here lay the groundwork for the modular calibration and operation of sparse spin qubit arrays.

cond-mat.mes-hallCross-listedarXiv:2601.23267•Feb 2, 2026•0 citations

Complete deterministic multi-electron Greenberger-Horne-Zeilinger state analyzer for quantum communication

Hai‐Rui Wei, Bao‐Cang Ren, Mei Zhang +2 more

We present a scheme for the multi-electron Greenberger-Horne-Zeilinger (GHZ) state analyzer, resorting to an interface between the polarization of a probe photon and the spin of an electron in a quantum dot embedded in a microcavity. All the multi-spin GHZ states can be completely discriminated by using single-photon detectors and linear optical elements. Our scheme has some features. First, it is a complete GHZ-state analyzer for multi-electron spin systems. Second, the initial entangled states remain after being identified and they can be used for a successive task. Third, the electron qubits are static and the photons play a role of a medium for information transfer, which has a good application in quantum repeater in which the electron qubits are used to store the information and the photon qubits are used to transfer the information between others.

arXiv:1209.4732•Sep 21, 2012•1 citation

Entanglement and separability of qubits systems related to measurement processes, Hilbert-Schmidt(HS)decompositions and general Bell states

Y. Ben-Aryeh

Separability and entanglement for n-qubits systems are quantified by using Hilbert-Schmidt (HS) decompositions in which the density matrices are decomposed into various terms representing certain one qubit, two-qubits,and larger qubits measurements. The present method is more general than previous methods for bipartite systems as it can be used for quantification of entanglement for large n-qubits systems.We demonstrate the use of such method by analyzing three qubits GHZ states, and three qubits general Bell states produced by a certain multiplications of Braid operators, operating on the computational basis of states. Quantum correlations are obtained by measuring all qubits of these systems, while a measurement of a part of the system gives only classical correlations. Quantification of entanglement for these systems is given by the use of HS decompositions.

arXiv:1412.0213•Nov 30, 2014•1 citation

Single-photon two-qubit entangled states: preparation and measurement

Yoon-Ho Kim

We implement experimentally a deterministic method to prepare and measure single-photon two-qubit entangled states, in which the polarization and the spatial modes of a single-photon each represent a quantum bit. All four single-photon Bell-states can be easily prepared and measured deterministically using linear optical elements alone.

Quantum Electronics and Laser Science Conference•Dec 10, 2005•0 citations
A complete, non-demolition procedure is established for measuring multi-qubit entangled states, such as the Bell-states and the GHZ-states, which is essential in certain processes of quantum communication, computation, and teleportation. No interaction between the individual parts of the entangled system, nor with any environment is required. A small probe (e.g. a single qubit) takes care of all interaction with the system, and is used repeatedly. The probe-qubit interaction is of the simplest form, and only this one type of interaction is required to perform a complete measurement. The process may be divided into elementary local operations and interactions, taking place sequentially as the probe visits each of the qubits. A shuttle mode is described, which may be repeated indefinitely. By the quantum Zeno effect, the entangled states can be maintained until released in a predictable state. This shuttle process is stable, and self-correcting, by virtue of the standard measurements performed repeatedly on the probe.
An approach for performing a local measurement on a set of complete nnn-qubit maximally entangled states via cavity QED is presented. The method operates essentially by creating a single photon in the cavity through one qubit and then performing a joint multiqubit phase shift on the remaining qubits with the assistance of the photon. It is shown that for three-level qubit systems, a complete set of 2n{2}^{n}2n nnn-qubit maximally entangled states can be measured simultaneously, deterministic and independent of the number of qubits. Hence, the method is very efficient for realizing multiqubit GHZ-state measurement which is important to quantum information processing and communication.
It is well-known that maximally entangled states such as the Greenberger-Horne-Zeilinger (GHZ) states, with the Bell states as the simplest examples, are widely exploited in quantum information and computation. We study the application of such maximally entangled states from the viewpoint of the GHZ transform, which is a unitary basis transformation from the product states to the GHZ states. The algebraic structure of the GHZ transform is made clear and representative examples for it are verified as multi-qubit Clifford gates. In this paper, we focus on the Bell transform as the simplest example of the GHZ transform and apply it to the reformulation of quantum circuit model of teleportation and the reformulation of the fault-tolerant construction of single-qubit gates and two-qubit gates in teleportation-based quantum computation. We clearly show that there exists a natural algebraic structure called the teleportation operator in terms of the Bell transform to catch essential points of quantum teleportation, and hence we expect that there would also exist interesting algebraic structures in terms of the GHZ transform to play important roles in quantum information and computation.
Recent advances in coherent spin shuttling have made sparse semiconductor spin qubit arrays an appealing solid-state platform to realize quantum processors. The dynamic and long-range connectivity enabled by shuttling is also essential for many quantum error-correction (QEC) schemes. Here, we demonstrate a silicon spin-qubit device that comprises a shuttling bus for coherently transporting qubits that can interact at four isolated locations we call bus stops. We dynamically populate the array and tune all single- and two-qubit operations using shuttling and quantum non-demolition (QND) spin measurements, without access to charge sensing in most of the device. We achieve universal control of the effective five-qubit processor and select the connectivity required to form a surface-code stabilizer plaquette that supports X- and Z-type parity checks up to weight-four. We use the parity checks to generate multi-qubit entanglement between all qubit combinations in the array and report the genuine entanglement of a five-qubit Greenberger-Horne-Zeilinger (GHZ) state, constituting the largest such state ever constructed with gate-defined semiconductor spins. This work opens immediate opportunities to pursue QEC experiments with spin qubits, and the protocols developed here lay the groundwork for the modular calibration and operation of sparse spin qubit arrays.
We present a scheme for the multi-electron Greenberger-Horne-Zeilinger (GHZ) state analyzer, resorting to an interface between the polarization of a probe photon and the spin of an electron in a quantum dot embedded in a microcavity. All the multi-spin GHZ states can be completely discriminated by using single-photon detectors and linear optical elements. Our scheme has some features. First, it is a complete GHZ-state analyzer for multi-electron spin systems. Second, the initial entangled states remain after being identified and they can be used for a successive task. Third, the electron qubits are static and the photons play a role of a medium for information transfer, which has a good application in quantum repeater in which the electron qubits are used to store the information and the photon qubits are used to transfer the information between others.
Separability and entanglement for n-qubits systems are quantified by using Hilbert-Schmidt (HS) decompositions in which the density matrices are decomposed into various terms representing certain one qubit, two-qubits,and larger qubits measurements. The present method is more general than previous methods for bipartite systems as it can be used for quantification of entanglement for large n-qubits systems.We demonstrate the use of such method by analyzing three qubits GHZ states, and three qubits general Bell states produced by a certain multiplications of Braid operators, operating on the computational basis of states. Quantum correlations are obtained by measuring all qubits of these systems, while a measurement of a part of the system gives only classical correlations. Quantification of entanglement for these systems is given by the use of HS decompositions.