Phonon Networks with Silicon-Vacancy Centers in Diamond Waveguides

Abstract

We propose and analyze a novel realization of a solid-state quantum network, where separated silicon-vacancy centers are coupled via the phonon modes of a quasi-one-dimensional diamond waveguide. In our approach, quantum states encoded in long-lived electronic spin states can be converted into propagating phonon wave packets and be reabsorbed efficiently by a distant defect center. Our analysis shows that under realistic conditions, this approach enables the implementation of high-fidelity, scalable quantum communication protocols within chip-scale spin-qubit networks. Apart from quantum information processing, this setup constitutes a novel waveguide QED platform, where strong-coupling effects between solid-state defects and individual propagating phonons can be explored at the quantum level.

Direct writing of single germanium vacancy center arrays in diamond

“…While the conversion yield is low at this point, this can be circumvented by employing larger implantation doses or other proven methods such as high temperature annealing and electron irradiation. More significantly, with the demonstrated technique, the GeV can be positioned with a nanometerscale spatial accuracy which will greatly benefit various of photonic structures such as photonic nano cavities [30][31][32] and waveguides [22,33]. Another possible direction is that this method can help generate coupled electron spins in germanium center as well as provide a platform to achieve entanglement between spins on the condition that the coherence time of GeV centers could be further enhanced.…”

Quantum state transfer via acoustic edge states in a 2D optomechanical array

“…In this case, quantum information can be stored in the long-lived spin degrees of freedom of the SiV ground state [58][59][60][61][62], where at low temperatures of T1 K coherence times exceeding T 2 ∼10 ms have been demonstrated [61,62]. At the same time the orbital degrees of freedom of the defect allow strong and tunable coupling to vibrational modes, as recently discussed in [28]. Combined with the ability to design chiral acoustic channels via OM interactions this coherent spin-phonon interface offers many new tools to overcome fundamental challenges in phononic quantum network applications.…”

“…As a first application for this setup we focus on the quantum-state transfer between TLS located in distant cavities via chiral acoustic edge channels. Compared to state transfer protocols in regular 1D phononic waveguides [23,26,28,29], this platform offers the advantages of a unidirectional propagation [35,[55][56][57], which is robust against local perturbations and where the direction can be controlled by external optical driving fields. While the basic protocol discussed in this work is very general, a naturally-suited system where these ideas can be implemented is an array of separated silicon vacancy (SiV) centers in a diamond OM crystal.…”

Quantum Dot Optomechanics in Suspended Nanophononic Strings

“…Our scheme could be also applied to QD‐molecules to dynamically switch coupling of charge and spin excitation by strain. Furthermore, our scheme can be directly applied to exciton and spin qubits of QD molecules or of optically active defect centers, for which recent proposals promise high fidelity quantum control schemes, or QDs forming in nanowires . Moreover, our work marks a first important step to interface optomechanical crystals with engineered dispersions of phonons and photons and operation frequencies in the GHz domain .…”