A single nitrogen-vacancy defect coupled to a nanomechanical oscillator

Abstract

A single Nitrogen Vacancy (NV) center hosted in a diamond nanocrystal is positioned at the extremity of a SiC nanowire. This novel hybrid system couples the degrees of freedom of two radically different systems, i.e. a nanomechanical oscillator and a single quantum object. The dynamics of the nano-resonator is probed through time resolved nanocrystal fluorescence and photon correlation measurements, conveying the influence of a mechanical degree of freedom given to a non-classical photon emitter. Moreover, by immersing the system in a strong magnetic field gradient, we induce a magnetic coupling between the nanomechanical oscillator and the NV electronic spin, providing nanomotion readout through a single electronic spin. Spin-dependent forces inherent to this coupling scheme are essential in a variety of active cooling and entanglement protocols used in atomic physics, and should now be within the reach of nanomechanical hybrid systems.Owing to recent developments in cavity opto-and electro-mechanics [1-3], it is now realistic to envision the observation of macroscopic mechanical oscillators cooled by active or traditional cryogenic techniques close to their ground state of motion. This conceptually elegant accomplishment would give access to a vast playground for physicists if the resonator wavefunction could be coherently manipulated such as to create, maintain and probe Fock or other non-classical states. It would provide a remarkable opportunity to extend the pioneering experiments with trapped ions [4] to encompass macroscopic objects. However, standard continuous measurements techniques used to actively cool and probe the resonator [5], when utilized to manipulate its quantum state, tend to blur its non-classical nature. An attractive alternative consists in interfacing the mechanical degrees of freedom with a single quantum object such as a 2-level system whose quantum state can be externally controlled [6][7][8][9][10][11]. Successful realization of this type of coupling between a nanomechanical oscillator in the quantum regime and a phase qubit was recently reported [12] and motivates the development of similar hybrid quantum systems presenting extended coherence times at room temperature and compatible with continuous measurement approaches.Here we report a first step in this direction by coupling a nanomechanical oscillator to a single negatively-charged Nitrogen Vacancy (NV) defect hosted in a diamond nanocrystal attached to its extremity (fig 1a). In that context, the NV defect appears as an attractive quantum system, both for its optical and electronic spin properties. Indeed, perfect photostability at room temperature makes the NV defect a robust and practical single-photon source [13,14]. Moreover, the NV defect ground state is a spin triplet (fig 1b) which can be initialized and read-out by optical means, and manipulated by resonant microwave excitation with an unprecedented coherence time for a solid-state system under ambient conditions [15,16]. Such properties are at the heart of diamond-base...

Suppression of spin-bath dynamics for improved coherence of multi-spin-qubit systems

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A universal and ultrasensitive vectorial nanomechanical sensor for imaging 2D force fields

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Optomechanical analog of two-color electromagnetically induced transparency: Photon transmission through an optomechanical device with a two-level system

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