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

Physical Review A

Generating maximally-path-entangled number states in two spin ensembles coupled to a superconducting flux qubit

Yusef Maleki, Aleksei M. Zheltikov

Published Jan 16, 2018• 27 citations
Publisher

Abstract

An ensemble of nitrogen-vacancy (NV) centers coupled to a circuit QED device is shown to enable an efficient, high-fidelity generation of high-N00N states. Instead of first creating entanglement and then increasing the number of entangled particles $N$, our source of high-N00N states first prepares a high-$N$ Fock state in one of the NV ensembles and then entangles it to the rest of the system. With such a strategy, high-$N$ N00N states can be generated in just a few operational steps with an extraordinary fidelity. Once prepared, such a state can be stored over a longer period of time due to the remarkably long coherence time of NV centers.

DOI
10.1103/physreva.97.012312

Related papers

Deterministic generation of a twin-Fock state of two nitrogen-vacancy ensembles via a superconducting flux qubit

Jin Xu, Tong Liu

The twin-Fock state plays a central role in quantum metrology and quantum information processing. Here, we propose a method to generate a twin-Fock state of two nitrogen-vacancy-center (NV) ensembles using a superconducting flux qubit. This state is deterministically prepared by simultaneously exciting two NV ensembles with the flux qubit. Numerical simulations demonstrate that twin-Fock states with n⩽6 can be prepared with high fidelity using current experimental technology. This proposal is universal and can be employed with other solid-state devices coupled to a superconducting qubit.

Applied Physics Letters•Oct 13, 2025•0 citations

Preparation of Macroscopic Entangled Coherent States in Nitrogen-Vacancy Centers Ensembles Coupled to a Superconducting Flux Qubit*

Liang-Wei Wang, Zhang-Cai Long

Abstract We propose a potentially practical scheme for creating macroscopic entangled coherent state between two separate nitrogen-vacancy center spin ensembles placed near a superconducting flux qubit. Through the collective magnetic coupling and the in situ tunability of the flux qubit, the arbitrary entangled coherent states of spin ensembles can be achieved with high success possibilities under the influence from decoherence of the flux qubit and spin ensembles. The experimental feasibility and challenge are justified using currently available technology.

Communications in Theoretical Physics•Jun 1, 2017•2 citations

One-step generation of multipartite entanglement among nitrogen-vacancy center ensembles

Wan-Lu Song, Zhang‐qi Yin, Wan-li Yang +3 more

We describe a one-step, deterministic and scalable scheme for creating macroscopic arbitrary entangled coherent states (ECSs) of separate nitrogen-vacancy center ensembles (NVEs) that couple to a superconducting flux qubit. We discuss how to generate the entangled states between the flux qubit and two NVEs by the resonant driving. Then the ECSs of the NVEs can be obtained by projecting the flux qubit, and the entanglement detection can be realized by transferring the quantum state from the NVEs to the flux qubit. Our numerical simulation shows that even under current experimental parameters the concurrence of the ECSs can approach unity. We emphasize that this method is straightforwardly extendable to the case of many NVEs.

Scientific Reports•Jan 13, 2015•26 citations

Controllable quantum state transfer and entanglement generation between distant nitrogen-vacancy-center ensembles coupled to superconducting flux qubits

Qiong Chen, Wan Li Yang, Mang Feng

We investigate the dissipative dynamics of a hybrid system consisting of two inductively coupled superconducting flux qubits (FQs), each of which couples magnetically with a nitrogen-vacancy-center spin ensemble (NVE). The system displays a series of damped oscillations under various experimental situations, where we obtain analytically the time-dependent populations associated with arbitrary values of the FQ-FQ inductively coupling strength $g$ and the FQ-NVE magnetically coupling strength $G$ in the one-excitation case. Our results show that a reliable high-fidelity quantum state transfer between the two distant NVEs can be realized by modulating the parameters $g$ and $G.$ Furthermore, we also present a potentially practical idea to entangle the two separate NVEs, which is within reach due to the currently available technology.

Physical Review A•Aug 24, 2012•35 citations

Coupling Nitrogen-Vacancy Centers in Diamond to Superconducting Flux Qubits

D. Marcos, Martijn Wubs, Jacob M. Taylor +3 more

We propose a method to achieve coherent coupling between nitrogen-vacancy (NV) centers in diamond and superconducting (SC) flux qubits. The resulting coupling can be used to create a coherent interaction between the spin states of distant NV centers mediated by the flux qubit. Furthermore, the magnetic coupling can be used to achieve a coherent transfer of quantum information between the flux qubit and an ensemble of NV centers. This enables a long-term memory for a SC quantum processor and possibly an interface between SC qubits and light.

arXiv:1001.4048•Physical Review Letters•Nov 17, 2010•258 citations

Towards Realizing a Quantum Memory for a Superconducting Qubit: Storage and Retrieval of Quantum States

Shiro Saito, Xiaobo Zhu, Robert Amsüss +7 more

We have built a hybrid system composed of a superconducting flux qubit (the processor) and an ensemble of nitrogen-vacancy centers in diamond (the memory) that can be directly coupled to one another, and demonstrated how information can be transferred from the flux qubit to the memory, stored, and subsequently retrieved. We have established the coherence properties of the memory and succeeded in creating an entangled state between the processor and memory, demonstrating how the entangled state's coherence is preserved. Our results are a significant step towards using an electron spin ensemble as a quantum memory for superconducting qubits.

arXiv:1308.5130•Physical Review Letters•Sep 5, 2013•112 citations
An ensemble of nitrogen-vacancy (NV) centers coupled to a circuit QED device is shown to enable an efficient, high-fidelity generation of high-N00N states. Instead of first creating entanglement and then increasing the number of entangled particles NNN, our source of high-N00N states first prepares a high-NNN Fock state in one of the NV ensembles and then entangles it to the rest of the system. With such a strategy, high-NNN N00N states can be generated in just a few operational steps with an extraordinary fidelity. Once prepared, such a state can be stored over a longer period of time due to the remarkably long coherence time of NV centers.
The twin-Fock state plays a central role in quantum metrology and quantum information processing. Here, we propose a method to generate a twin-Fock state of two nitrogen-vacancy-center (NV) ensembles using a superconducting flux qubit. This state is deterministically prepared by simultaneously exciting two NV ensembles with the flux qubit. Numerical simulations demonstrate that twin-Fock states with n⩽6 can be prepared with high fidelity using current experimental technology. This proposal is universal and can be employed with other solid-state devices coupled to a superconducting qubit.
Abstract We propose a potentially practical scheme for creating macroscopic entangled coherent state between two separate nitrogen-vacancy center spin ensembles placed near a superconducting flux qubit. Through the collective magnetic coupling and the in situ tunability of the flux qubit, the arbitrary entangled coherent states of spin ensembles can be achieved with high success possibilities under the influence from decoherence of the flux qubit and spin ensembles. The experimental feasibility and challenge are justified using currently available technology.
We describe a one-step, deterministic and scalable scheme for creating macroscopic arbitrary entangled coherent states (ECSs) of separate nitrogen-vacancy center ensembles (NVEs) that couple to a superconducting flux qubit. We discuss how to generate the entangled states between the flux qubit and two NVEs by the resonant driving. Then the ECSs of the NVEs can be obtained by projecting the flux qubit, and the entanglement detection can be realized by transferring the quantum state from the NVEs to the flux qubit. Our numerical simulation shows that even under current experimental parameters the concurrence of the ECSs can approach unity. We emphasize that this method is straightforwardly extendable to the case of many NVEs.
We investigate the dissipative dynamics of a hybrid system consisting of two inductively coupled superconducting flux qubits (FQs), each of which couples magnetically with a nitrogen-vacancy-center spin ensemble (NVE). The system displays a series of damped oscillations under various experimental situations, where we obtain analytically the time-dependent populations associated with arbitrary values of the FQ-FQ inductively coupling strength ggg and the FQ-NVE magnetically coupling strength GGG in the one-excitation case. Our results show that a reliable high-fidelity quantum state transfer between the two distant NVEs can be realized by modulating the parameters ggg and G.G.G. Furthermore, we also present a potentially practical idea to entangle the two separate NVEs, which is within reach due to the currently available technology.
We propose a method to achieve coherent coupling between nitrogen-vacancy (NV) centers in diamond and superconducting (SC) flux qubits. The resulting coupling can be used to create a coherent interaction between the spin states of distant NV centers mediated by the flux qubit. Furthermore, the magnetic coupling can be used to achieve a coherent transfer of quantum information between the flux qubit and an ensemble of NV centers. This enables a long-term memory for a SC quantum processor and possibly an interface between SC qubits and light.
We have built a hybrid system composed of a superconducting flux qubit (the processor) and an ensemble of nitrogen-vacancy centers in diamond (the memory) that can be directly coupled to one another, and demonstrated how information can be transferred from the flux qubit to the memory, stored, and subsequently retrieved. We have established the coherence properties of the memory and succeeded in creating an entangled state between the processor and memory, demonstrating how the entangled state's coherence is preserved. Our results are a significant step towards using an electron spin ensemble as a quantum memory for superconducting qubits.