Single-nitrogen-vacancy-center quantum memory for a superconducting flux qubit mediated by a ferromagnet

We propose a quantum memory scheme to transfer and store the quantum state of a superconducting flux qubit (FQ) into the electron spin of a single nitrogen-vacancy (NV) center in diamond via yttrium iron garnet (YIG), a ferromagnet. Unlike an ensemble of NV centers, the YIG moderator can enhance the effective FQ-NV-center coupling strength without introducing additional appreciable decoherence. We derive the effective interaction between the FQ and the NV center by tracing out the degrees of freedom of the collective mode of the YIG spins. We demonstrate the transfer, storage, and retrieval procedures, taking into account the effects of spontaneous decay and pure dephasing. Using realistic experimental parameters for the FQ, NV center and YIG, we find that a combined transfer, storage, and retrieval fidelity higher than 0.9, with a long storage time of 10 ms, can be achieved. This hybrid system not only acts as a promising quantum memory, but also provides an example of enhanced coupling between various systems through collective degrees of freedom.

[1]  Yasunobu Nakamura,et al.  Bidirectional conversion between microwave and light via ferromagnetic magnons , 2016, 1601.03908.

[2]  Neil B. Manson,et al.  The nitrogen-vacancy colour centre in diamond , 2013, 1302.3288.

[3]  J. Clarke,et al.  The flux qubit revisited to enhance coherence and reproducibility , 2015, Nature Communications.

[4]  F. Nori,et al.  Quantum memory using a hybrid circuit with flux qubits and nitrogen-vacancy centers , 2013, 1301.1504.

[5]  Tom Douce,et al.  Coupling a single nitrogen-vacancy center to a superconducting flux qubit in the far-off-resonance regime , 2015 .

[6]  A R Plummer,et al.  Introduction to Solid State Physics , 1967 .

[7]  H. Primakoff,et al.  Field dependence of the intrinsic domain magnetization of a ferromagnet , 1940 .

[8]  D. DiVincenzo,et al.  Schrieffer-Wolff transformation for quantum many-body systems , 2011, 1105.0675.

[9]  D Budker,et al.  Solid-state electronic spin coherence time approaching one second , 2012, Nature Communications.

[10]  J. Clarke,et al.  Superconducting quantum bits , 2008, Nature.

[11]  Kae Nemoto,et al.  Coherent coupling of a superconducting flux qubit to an electron spin ensemble in diamond , 2011, Nature.

[12]  F. Nori,et al.  Cavity quantum electrodynamics with ferromagnetic magnons in a small yttrium-iron-garnet sphere , 2015, npj Quantum Information.

[13]  D. Loss,et al.  Long-Distance Entanglement of Spin Qubits via Ferromagnet , 2013, 1302.4017.

[14]  F. Nori,et al.  Hybrid quantum circuits: Superconducting circuits interacting with other quantum systems , 2012, 1204.2137.

[15]  C. Jooss,et al.  Straightforward field calculations for uniaxial hardmagnetic prisms: stray field distributions and dipolar coupling in regular arrays , 2008 .

[16]  S Onoda,et al.  Hybrid quantum circuit with a superconducting qubit coupled to a spin ensemble. , 2011, Physical review letters.

[17]  Yasunobu Nakamura,et al.  Quantum magnonics: The magnon meets the superconducting qubit , 2015, 1508.05290.

[18]  I. Kolokolov,et al.  The saga of YIG: Spectra, thermodynamics, interaction and relaxation of magnons in a complex magnet , 1993 .

[19]  J. Woodward,et al.  Rapid rise time pulsed magnetic field circuit for pump-probe field effect studies. , 2007, The Review of scientific instruments.

[20]  J. Prieto,et al.  Measurement of the intrinsic damping constant in individual nanodisks of YIG and YIGjPt , 2014, 1402.3630.

[21]  J Wrachtrup,et al.  Strong coupling of a spin ensemble to a superconducting resonator. , 2010, Physical review letters.

[22]  G Catelani,et al.  Flux qubits with long coherence times for hybrid quantum circuits. , 2014, Physical review letters.

[23]  Salomaa.  Schrieffer-Wolff transformation for the Anderson Hamiltonian in a superconductor. , 1988, Physical review. B, Condensed matter.

[24]  H. Carmichael.  Statistical Methods in Quantum Optics 1 , 1999 .

[25]  R. Stephenson.  A and V , 1962, The British journal of ophthalmology.

[26]  Patrick Maletinsky,et al.  High-efficiency resonant amplification of weak magnetic fields for single spin magnetometry at room temperature. , 2014, Nature nanotechnology.

[27]  Yasunobu Nakamura,et al.  Coherent coupling between a ferromagnetic magnon and a superconducting qubit , 2014, Science.

[28]  Yasunobu Nakamura,et al.  Hybridizing ferromagnetic magnons and microwave photons in the quantum limit. , 2014, Physical review letters.

[29]  S. Barrett,et al.  Superconducting cavity bus for single nitrogen-vacancy defect centers in diamond , 2009, 0912.3586.

[30]  M. Scully,et al.  Statistical Methods in Quantum Optics 1: Master Equations and Fokker-Planck Equations , 2003 .

[31]  J. Schrieffer,et al.  Relation between the Anderson and Kondo Hamiltonians , 1966 .

[32]  Charles Santori,et al.  Optical and spin coherence properties of nitrogen-vacancy centers placed in a 100 nm thick isotopically purified diamond layer. , 2012, Nano letters.