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:0912.3586 · Physical Review B

Superconducting cavity bus for single nitrogen-vacancy defect centers in diamond

Jason Twamley, S. D. Barrett

Published Jun 11, 2010• 85 citations
arXivHTMLPDF

Abstract

Circuit-QED has demonstrated very strong coupling between light and matter, and has the potential to engineer large quantum devices. Hybrid designs have been proposed which couple large ensembles of atomic and molecular systems to the superconducting resonator. We show that one can achieve an effective strong coupling between light and matter for much smaller ensembles (and even a single electronic spin), through the use of an interconnecting quantum system: in our case a persistent current qubit. Using this interconnect we show that one can effectively magnify the coupling strength between the light and matter by over five orders of magnitude $g\ensuremath{\sim}7\text{ }\text{Hz}\ensuremath{\rightarrow}100\text{ }\text{kHz}$ and enter a regime where a single nitrogen-vacancy (NV) electronic spin can shift the cavity resonance line by over $\ensuremath{\sim}20$ linewidths. With such strong coupling between an individual electronic spin in an NV and the light in the resonator, one has the potential build devices where the associated NV nuclear spins can be strongly coupled over centimeters via the superconducting bus.

DOI
10.1103/physrevb.81.241202

Related papers

Coupling a single NV center to a superconducting flux qubit via a nanomechanical resonator

Xinke Li, Sheng-li Ma, Ya-long Ren +2 more

We investigate the hybrid quantum system of a superconducting flux qubit, a single electronic spin associated with a negatively charged nitrogen vacancy (NV) center in diamond, and a high-quality magnetized nanomechanical resonator (NAMR). It is shown that the quantized motion of the NAMR can strongly couple to both the NV spin and the flux qubit. We estimate that the coupling strength of the NAMR to both the NV spin and the flux qubit can be about 2 π × 100 kHz, which is one order of magnitude larger than direct spin–qubit coupling. This enables the quantum state transfer to be faster and more robust against decoherence. The present work may provide an appealing way for quantum information processing based on hybrid solid-state quantum systems.

Journal of the Optical Society of America B•Nov 16, 2021•5 citations

Quantum interface between a transmon qubit and spins of nitrogen-vacancy centers

Yaowen Hu, Yipu Song, Luming Duan

Hybrid quantum circuits combining advantages of each individual system have provided a promising platform for quantum information processing. Here we propose an experimental scheme to directly couple a transmon qubit to an individual spin in the nitrogen-vacancy (NV) center, with a coupling strength three orders of magnitude larger than that for a single spin coupled to a coplanar waveguide microwave cavity. This direct coupling between the transmon and the NV center could be utilized to make a transmon bus, leading to a coherently virtual exchange among different single spins. Furthermore, we demonstrate that, by coupling a transmon to a low-density NV ensemble, a swap operation between the transmon and NV ensemble is feasible and a quantum nondemolition measurement on the state of the NV ensemble can be realized on the cavity-transmon-NV-ensemble hybrid system. Moreover, in this system, a virtual coupling can be achieved between the cavity and NV ensemble, which is much larger in magnitude than the direct coupling between the cavity and the NV ensemble. The photon state in the cavity can thus be stored into NV spins more efficiently through this virtual coupling.

arXiv:1709.08508•Physical Review A•Dec 1, 2017•12 citations

Strong Coupling of a Spin Ensemble to a Superconducting Resonator

Yuimaru Kubo, Florian R. Ong, Patrice Bertet +11 more

We report the realization of a quantum circuit in which an ensemble of electronic spins is coupled to a frequency tunable superconducting resonator. The spins are nitrogen-vacancy centers in a diamond crystal. The achievement of strong coupling is manifested by the appearance of a vacuum Rabi splitting in the transmission spectrum of the resonator when its frequency is tuned through the nitrogen-vacancy center electron spin resonance.

arXiv:1006.0251•Physical Review Letters•Sep 27, 2010•642 citations

Cavity QED with Magnetically Coupled Collective Spin States

Robert Amsüss, Christian Koller, Tobias Nöbauer +9 more

We report strong coupling between an ensemble of nitrogen-vacancy center electron spins in diamond and a superconducting microwave coplanar waveguide resonator. The characteristic scaling of the collective coupling strength with the square root of the number of emitters is observed directly. Additionally, we measure hyperfine coupling to (13)C nuclear spins, which is a first step towards a nuclear ensemble quantum memory. Using the dispersive shift of the cavity resonance frequency, we measure the relaxation time of the NV center at millikelvin temperatures in a nondestructive way.

arXiv:1103.1045•Physical Review Letters•Aug 3, 2011•330 citations

Robust quantum state transfer between a Cooper-pair box and diamond nitrogen-vacancy centers

Zhi‐Bo Feng

We propose a potentially practical scheme for quantum state transfer between a Cooper-pair box circuit and an electron spin ensemble of diamond nitrogen-vacancy (NV) centers. Both subsystems are placed into a common circuit QED and can be modeled as effective three-level subsystems under the appropriate external biases. Due to significant suppression of the photon decay, the robust state transfer between the two subsystems can be accomplished by using the technique of stimulated Raman adiabatic passage by individual microwave pulses, where a superconducting coplanar resonator serves as the quantum data bus. Numerical simulations show that the present scheme could offer a viable route towards robust quantum state transfer in hybrid solid-state systems.

Physical Review A•Mar 13, 2015•26 citations

Entanglement of quantum node based on hybrid system of diamond nitrogen-vacancy center spin ensembles and superconducting quantum circuits

Xueqin Li, Zhao Yun-Fang, Tang Yan-ni +1 more

Quantum entanglement is a kernel of quantum computation and quantum communication. We introduce a theoretical scheme to achieve the entanglement between two separated quantum nodes in a hybrid system. The proposed hybrid system based on diamond nitrogen-vacancy (NV) center spin ensemble is coherently coupled to a superconducting quantum circuit consisting of two quantum nodes and a quantum channel. Each node in our setup is composed of an NV center spin ensemble magnetically coupled to a superconducting coplanar resonator. The NV center spin ensemble composed of N identical and non-interacting NV spins, is placed in the magnetic field antinode of the superconducting coplanar resonator where the coupling is maximized. An array of superconducting quantum interference devices (SQUIDs) is inserted in the central conductor of resonator to make its frequency tunable with the magnetic flux threading through the SQUID loops. This flux is generated by passing current through an on-chip wire, so that the resonator can be brought in resonance with the NV center spins without changing their Zeeman splitting. Quantum qubits encoded into two separate nodes are connected by a vacuum superconducting coplanar resonator that is used as a quantum channel. This setup can potentially take the best elements of each individual system:NV center spin ensemble with longer coherence time capable of preparing, storing and releasing photonic quantum information, and the superconducting quantum circuits are easy to manipulate externally and can perform quantum logic gates to control quantum information rapidly. In order to realize the entanglement between two separated quantum nodes, firstly, we make a canonical transformation and obtain the Hamiltonian of the system that is reduced to two NV center spin ensembles resonantly coupled to a single mode of the superconducting coplanar resonator. Then we put forward the hybrid NV center spin-photon qubit encoding. In this hybrid encoding, the NV center spin and photon degrees of freedom enter on an equal footing into the definition of the qubit, in which case, quantum channel will switch on when three superconducting coplanar resonators are in resonance with each other, and all the manipulations can perform simply by tuning the frequencies of the superconducting coplanar resonators. Under the precise control of the evolution time, high fidelity entanglement between two separated quantum nodes is achieved. We show that this proposal can provide high fidelity quantum entanglement under realistic conditions, both in the resonant and the dispersive interaction cases. This hybrid quantum system will exhibit long coherence time and possess features like easy fabrication, integratability, and potential scalability. Furthermore, the quantum node composed of an NV center spin ensemble magnetically coupled to a superconducting coplanar resonator can be respectively integrated, which has practical applications in the realization of quantum information transmission and quantum entanglement among multiple quantum nodes.

Acta Physica Sinica•Jan 1, 2018•2 citations
Circuit-QED has demonstrated very strong coupling between light and matter, and has the potential to engineer large quantum devices. Hybrid designs have been proposed which couple large ensembles of atomic and molecular systems to the superconducting resonator. We show that one can achieve an effective strong coupling between light and matter for much smaller ensembles (and even a single electronic spin), through the use of an interconnecting quantum system: in our case a persistent current qubit. Using this interconnect we show that one can effectively magnify the coupling strength between the light and matter by over five orders of magnitude g\ensuremath∼7 Hz\ensuremath→100 kHzg\ensuremath{\sim}7\text{ }\text{Hz}\ensuremath{\rightarrow}100\text{ }\text{kHz}g\ensuremath∼7 Hz\ensuremath→100 kHz and enter a regime where a single nitrogen-vacancy (NV) electronic spin can shift the cavity resonance line by over \ensuremath∼20\ensuremath{\sim}20\ensuremath∼20 linewidths. With such strong coupling between an individual electronic spin in an NV and the light in the resonator, one has the potential build devices where the associated NV nuclear spins can be strongly coupled over centimeters via the superconducting bus.
We investigate the hybrid quantum system of a superconducting flux qubit, a single electronic spin associated with a negatively charged nitrogen vacancy (NV) center in diamond, and a high-quality magnetized nanomechanical resonator (NAMR). It is shown that the quantized motion of the NAMR can strongly couple to both the NV spin and the flux qubit. We estimate that the coupling strength of the NAMR to both the NV spin and the flux qubit can be about 2 π × 100 kHz, which is one order of magnitude larger than direct spin–qubit coupling. This enables the quantum state transfer to be faster and more robust against decoherence. The present work may provide an appealing way for quantum information processing based on hybrid solid-state quantum systems.
Hybrid quantum circuits combining advantages of each individual system have provided a promising platform for quantum information processing. Here we propose an experimental scheme to directly couple a transmon qubit to an individual spin in the nitrogen-vacancy (NV) center, with a coupling strength three orders of magnitude larger than that for a single spin coupled to a coplanar waveguide microwave cavity. This direct coupling between the transmon and the NV center could be utilized to make a transmon bus, leading to a coherently virtual exchange among different single spins. Furthermore, we demonstrate that, by coupling a transmon to a low-density NV ensemble, a swap operation between the transmon and NV ensemble is feasible and a quantum nondemolition measurement on the state of the NV ensemble can be realized on the cavity-transmon-NV-ensemble hybrid system. Moreover, in this system, a virtual coupling can be achieved between the cavity and NV ensemble, which is much larger in magnitude than the direct coupling between the cavity and the NV ensemble. The photon state in the cavity can thus be stored into NV spins more efficiently through this virtual coupling.
We report strong coupling between an ensemble of nitrogen-vacancy center electron spins in diamond and a superconducting microwave coplanar waveguide resonator. The characteristic scaling of the collective coupling strength with the square root of the number of emitters is observed directly. Additionally, we measure hyperfine coupling to (13)C nuclear spins, which is a first step towards a nuclear ensemble quantum memory. Using the dispersive shift of the cavity resonance frequency, we measure the relaxation time of the NV center at millikelvin temperatures in a nondestructive way.
We propose a potentially practical scheme for quantum state transfer between a Cooper-pair box circuit and an electron spin ensemble of diamond nitrogen-vacancy (NV) centers. Both subsystems are placed into a common circuit QED and can be modeled as effective three-level subsystems under the appropriate external biases. Due to significant suppression of the photon decay, the robust state transfer between the two subsystems can be accomplished by using the technique of stimulated Raman adiabatic passage by individual microwave pulses, where a superconducting coplanar resonator serves as the quantum data bus. Numerical simulations show that the present scheme could offer a viable route towards robust quantum state transfer in hybrid solid-state systems.
Quantum entanglement is a kernel of quantum computation and quantum communication. We introduce a theoretical scheme to achieve the entanglement between two separated quantum nodes in a hybrid system. The proposed hybrid system based on diamond nitrogen-vacancy (NV) center spin ensemble is coherently coupled to a superconducting quantum circuit consisting of two quantum nodes and a quantum channel. Each node in our setup is composed of an NV center spin ensemble magnetically coupled to a superconducting coplanar resonator. The NV center spin ensemble composed of N identical and non-interacting NV spins, is placed in the magnetic field antinode of the superconducting coplanar resonator where the coupling is maximized. An array of superconducting quantum interference devices (SQUIDs) is inserted in the central conductor of resonator to make its frequency tunable with the magnetic flux threading through the SQUID loops. This flux is generated by passing current through an on-chip wire, so that the resonator can be brought in resonance with the NV center spins without changing their Zeeman splitting. Quantum qubits encoded into two separate nodes are connected by a vacuum superconducting coplanar resonator that is used as a quantum channel. This setup can potentially take the best elements of each individual system:NV center spin ensemble with longer coherence time capable of preparing, storing and releasing photonic quantum information, and the superconducting quantum circuits are easy to manipulate externally and can perform quantum logic gates to control quantum information rapidly. In order to realize the entanglement between two separated quantum nodes, firstly, we make a canonical transformation and obtain the Hamiltonian of the system that is reduced to two NV center spin ensembles resonantly coupled to a single mode of the superconducting coplanar resonator. Then we put forward the hybrid NV center spin-photon qubit encoding. In this hybrid encoding, the NV center spin and photon degrees of freedom enter on an equal footing into the definition of the qubit, in which case, quantum channel will switch on when three superconducting coplanar resonators are in resonance with each other, and all the manipulations can perform simply by tuning the frequencies of the superconducting coplanar resonators. Under the precise control of the evolution time, high fidelity entanglement between two separated quantum nodes is achieved. We show that this proposal can provide high fidelity quantum entanglement under realistic conditions, both in the resonant and the dispersive interaction cases. This hybrid quantum system will exhibit long coherence time and possess features like easy fabrication, integratability, and potential scalability. Furthermore, the quantum node composed of an NV center spin ensemble magnetically coupled to a superconducting coplanar resonator can be respectively integrated, which has practical applications in the realization of quantum information transmission and quantum entanglement among multiple quantum nodes.