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:1104.1022 · Physical Review B

Greenberger-Horne-Zeilinger generation protocol for N superconducting transmon qubits capacitively coupled to a quantum bus

Samuel Aldana, Ying-Dan Wang, Christoph Bruder

Published Oct 17, 2011• 29 citations
arXivHTMLPDF

Abstract

We propose a circuit quantum electrodynamics (QED) realization of a protocol to generate a Greenberger-Horne-Zeilinger (GHZ) state for $N$ superconducting transmon qubits homogeneously coupled to a superconducting transmission line resonator in the dispersive limit. We derive an effective Hamiltonian with pairwise qubit exchange interactions of the $XY$ type, $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{g}(XX+YY)$, that can be globally controlled. Starting from a separable initial state, these interactions allow us to generate a multi-qubit GHZ state within a time ${t}_{\mathrm{GHZ}}\ensuremath{\sim}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{g}}^{\ensuremath{-}1}$. We discuss how to probe the nonlocal nature and the genuine $N$-partite entanglement of the generated state. Finally, we investigate the stability of the proposed scheme to inhomogeneities in the physical parameters.

DOI
10.1103/physrevb.84.134519

Related papers

One-step multiqubit Greenberger-Horne-Zeilinger state generation in a circuit QED system

Ying-Dan Wang, Stefano Chesi, Daniel Loss +1 more

We propose a one-step scheme to generate Greenberger-Horne-Zeilinger (GHZ) states for superconducting flux qubits or charge qubits in a circuit QED setup. The GHZ state can be produced within the coherence time of the multiqubit system. Our scheme is independent of the initial state of the transmission line resonator and works in the presence of higher harmonic modes. Our analysis also shows that the scheme is robust to various operation errors and environmental noise.

arXiv:0911.1396•Physical Review B•Mar 24, 2010•61 citations

Practical one-step synthesis of multipartite entangled states on superconducting circuits

Rui Tao, Xiao-Tao Mo, Zheng‐Yuan Xue +1 more

Quantum entanglement is an important resource for quantum information processing tasks. However, realistic multipartite entangled state production is very difficult. In this paper, we propose an efficient single-step scheme for generating many body Greenberger–Horne–Zeilinger (GHZ) states on superconducting circuits by using a superconducting transmission-line resonator (TLR) interact with [Formula: see text] superconducting transmon qubits. The distinct merit of our proposal is that it does not require the qubit-resonator coupling strengths to be the same, which is usually impractical experimentally, and thus is one of the main reasons for entanglement generation infidelity in previous single-step schemes. The removing of the uniform interaction requirement is achieved by modulating the qubits splitting frequencies with ac microwave fields, which results in tunable individual qubit-resonator coupling strength, and thus effective uniform qubit–qubit interaction Hamiltonian can be obtained. Since microwave control is conventional nowadays, our proposal can be directly tested experimentally, which makes previous multipartite entangled states generation schemes more efficient.

International Journal of Quantum Information•Oct 1, 2019•0 citations

Generation of Greenberger-Horne-Zeilinger States on Two-Dimensional Superconducting-Qubit Lattices via Parallel Multiqubit-Gate Operations

Wei Feng, Guo-Qiang Zhang, Qi-Ping Su +2 more

A recent major technological breakthrough in superconducting circuits is the realization of more than 50 qubits arranged on two-dimensional (2D) lattices with tunable nearest-neighbor couplings. We propose a protocol to generate Greenberger-Horne-Zeilinger (GHZ) states on 2D superconducting-qubit lattices by applying multiqubit controlled-$i$swap gates in parallel. The multiqubit gate can be naturally implemented based on an effective three-body interaction, which can be synthesized with appropriate detunings and coupling strengths between qubits. We simulate the preparation process of GHZ states with realistic parameters, and show a $37$-qubit GHZ state can be generated with a controlled-$i$swap depth of $3$. Our proposal provides a more promising method of generating GHZ states on the latest 2D superconducting-qubit architectures and will stimulate the preparation of multiqubit entangled states based on multiqubit gates.

Physical Review Applied•Dec 13, 2022•18 citations

Deterministic generation of Greenberger–Horne–Zeilinger entangled states of cat-state qubits in circuit QED

Chui‐Ping Yang, Zhen-Fei Zheng

We present an efficient method to generate a Greenberger-Horne-Zeilinger (GHZ) entangled state of three cat-state qubits via circuit QED. The GHZ state is prepared with three microwave cavities coupled to a superconducting transmon qutrit. Because the qutrit remains in the ground state during the operation, decoherence caused by the energy relaxation and dephasing of the qutrit is greatly suppressed. The GHZ state is created deterministically, because no measurement is involved. Numerical simulations show that the high-fidelity generation of a three-cqubit GHZ state is feasible with the present circuit QED technology. This proposal can be easily extended to create a N-cqubit GHZ state (N≥3), with N microwave or optical cavities coupled to a natural or artificial three-level atom.

arXiv:1910.08226•Optics Letters•Oct 12, 2018•29 citations

Fast generation of multiparticle entangled state for flux qubits in a circle array of transmission line resonators with tunable coupling

Zhihui Peng, Yu-xi Liu, Yasunobu Nakamura +1 more

We study a one-step approach to the fast generation of Greenberger-Horne-Zeilinger (GHZ) states in a circuit QED system with superconducting flux qubits. The GHZ state can be generated in about 10 ns, which is much shorter than the coherence time of flux qubits and comparable with the time of single-qubit operation. In our proposal a time-dependent microwave field is applied to a superconducting transmission line resonator (TLR) and displaces the resonator in a controlled manner, thus inducing indirect qubit-qubit coupling without residual entanglement between the qubits and the resonator. The design of a tunably coupled TLR circle array provides us with the potential for extending this one-step scheme to the case of many qubits coupled via several TLRs.

arXiv:1111.5676•Physical Review B•Jan 30, 2012•22 citations

One-Step Generation of Multi-Qubit GHZ and W States in Superconducting Transmon Qubit System

Gui-Long Gao, Gen-Chang Cai, Shou-Sheng Huang +2 more

We propose a one-step method to prepare multi-qubit GHZ and W states with transmon qubits capacitively coupled to a superconducting transmission line resonator (TLR). Compared with the scheme firstly introduced by Wang et al. [ Phys. Rev. B 81 (2010) 104524 ], our schemes have longer dephasing time and much shorter operation time because the transmon qubits we used are not only more robust to the decoherence and the unavoidable parameter variations, but also have much stronger coupling constant with TLR. Based on the favourable properties of transmons and TLR, our method is more feasible in experiment.

Communications in Theoretical Physics•Feb 1, 2012•3 citations
We propose a circuit quantum electrodynamics (QED) realization of a protocol to generate a Greenberger-Horne-Zeilinger (GHZ) state for NNN superconducting transmon qubits homogeneously coupled to a superconducting transmission line resonator in the dispersive limit. We derive an effective Hamiltonian with pairwise qubit exchange interactions of the XYXYXY type, g\ifmmode~\else˜\fi(XX+YY)\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{g}(XX+YY)g\ifmmode~\else˜\fi​(XX+YY), that can be globally controlled. Starting from a separable initial state, these interactions allow us to generate a multi-qubit GHZ state within a time tGHZ\ensuremath∼g\ifmmode~\else˜\fi\ensuremath−1{t}_{\mathrm{GHZ}}\ensuremath{\sim}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{g}}^{\ensuremath{-}1}tGHZ​\ensuremath∼g\ifmmode~\else˜\fi​\ensuremath−1. We discuss how to probe the nonlocal nature and the genuine NNN-partite entanglement of the generated state. Finally, we investigate the stability of the proposed scheme to inhomogeneities in the physical parameters.
Quantum entanglement is an important resource for quantum information processing tasks. However, realistic multipartite entangled state production is very difficult. In this paper, we propose an efficient single-step scheme for generating many body Greenberger–Horne–Zeilinger (GHZ) states on superconducting circuits by using a superconducting transmission-line resonator (TLR) interact with [Formula: see text] superconducting transmon qubits. The distinct merit of our proposal is that it does not require the qubit-resonator coupling strengths to be the same, which is usually impractical experimentally, and thus is one of the main reasons for entanglement generation infidelity in previous single-step schemes. The removing of the uniform interaction requirement is achieved by modulating the qubits splitting frequencies with ac microwave fields, which results in tunable individual qubit-resonator coupling strength, and thus effective uniform qubit–qubit interaction Hamiltonian can be obtained. Since microwave control is conventional nowadays, our proposal can be directly tested experimentally, which makes previous multipartite entangled states generation schemes more efficient.
A recent major technological breakthrough in superconducting circuits is the realization of more than 50 qubits arranged on two-dimensional (2D) lattices with tunable nearest-neighbor couplings. We propose a protocol to generate Greenberger-Horne-Zeilinger (GHZ) states on 2D superconducting-qubit lattices by applying multiqubit controlled-iiiswap gates in parallel. The multiqubit gate can be naturally implemented based on an effective three-body interaction, which can be synthesized with appropriate detunings and coupling strengths between qubits. We simulate the preparation process of GHZ states with realistic parameters, and show a 373737-qubit GHZ state can be generated with a controlled-iiiswap depth of 333. Our proposal provides a more promising method of generating GHZ states on the latest 2D superconducting-qubit architectures and will stimulate the preparation of multiqubit entangled states based on multiqubit gates.
We present an efficient method to generate a Greenberger-Horne-Zeilinger (GHZ) entangled state of three cat-state qubits via circuit QED. The GHZ state is prepared with three microwave cavities coupled to a superconducting transmon qutrit. Because the qutrit remains in the ground state during the operation, decoherence caused by the energy relaxation and dephasing of the qutrit is greatly suppressed. The GHZ state is created deterministically, because no measurement is involved. Numerical simulations show that the high-fidelity generation of a three-cqubit GHZ state is feasible with the present circuit QED technology. This proposal can be easily extended to create a N-cqubit GHZ state (N≥3), with N microwave or optical cavities coupled to a natural or artificial three-level atom.
We study a one-step approach to the fast generation of Greenberger-Horne-Zeilinger (GHZ) states in a circuit QED system with superconducting flux qubits. The GHZ state can be generated in about 10 ns, which is much shorter than the coherence time of flux qubits and comparable with the time of single-qubit operation. In our proposal a time-dependent microwave field is applied to a superconducting transmission line resonator (TLR) and displaces the resonator in a controlled manner, thus inducing indirect qubit-qubit coupling without residual entanglement between the qubits and the resonator. The design of a tunably coupled TLR circle array provides us with the potential for extending this one-step scheme to the case of many qubits coupled via several TLRs.
We propose a one-step method to prepare multi-qubit GHZ and W states with transmon qubits capacitively coupled to a superconducting transmission line resonator (TLR). Compared with the scheme firstly introduced by Wang et al. [ Phys. Rev. B 81 (2010) 104524 ], our schemes have longer dephasing time and much shorter operation time because the transmon qubits we used are not only more robust to the decoherence and the unavoidable parameter variations, but also have much stronger coupling constant with TLR. Based on the favourable properties of transmons and TLR, our method is more feasible in experiment.