Spin coherent quantum transport of electrons between defects in diamond

Abstract

The nitrogen-vacancy color center in diamond has rapidly emerged as an important solid-state system for quantum information processing. While individual spin registers have been used to implement small-scale diamond quantum computing, the realization of a large-scale device requires development of an on-chip quantum bus for transporting information between distant qubits. Here we propose a method for coherent quantum transport of an electron and its spin state between distant NV centers. Transport is achieved by the implementation of spatial stimulated adiabatic Raman passage through the optical control of the NV center charge states and the confined conduction states of a diamond nanostructure. Our models show that for two NV centers in a diamond nanowire, high fidelity transport can be achieved over distances of order hundreds of nanometres in timescales of order hundreds of nanoseconds. Spatial adiabatic passage is therefore a promising option for realizing an on-chip spin quantum bus. 1 arXiv:1905.07084v1 [quant-ph]

Spin-to-Charge conversion with electrode confinement in diamond

“…The equation is a sum of all the interactions of the phonon modes ψ k ( r) with the discretised energy levels of the conduction band minimum from 1 to n, integrated over the phonon k-space. The phonons have a wavelength ω k and a temperature dependent distribution given by a Bose-Einstein distribution n B [19]. The phonon modes can be calculated by understanding that e-p scattering only occurs with dilational modes as they are the only modes with a non-zero divergence.…”

“…The technique promises to vastly improve the fidelity of spin readout which has applications for NV based quantum sensing, communications and computation. The design also creates a discrete three level system for stimulated Raman adiabatic passage (STIRAP) experiments [19]. The key to this process is ensuring that the spectral lines are narrow enough to be resolved.…”

“…This process can occur when ionizing from m s = 0 to the conduction band or m s = ±1 to the conduction band. Fine structure of the first two conduction band states is negligible due to the fact that there is no spin-orbit effects in the conduction band minimum [19].…”

Probing charge dynamics in diamond with an individual color center

“…A deeper understanding of the dynamics of charge carriers in diamond is required in order to move beyond isolated color centers to arrays. 6,8,17 In this work, we use an individual NV center to study charge dynamics in diamond. These dynamics include optically changing a defect's charge state through the photogeneration of free charge carriers from that defect, as well as the transport and capture of these charge carriers by other defects.…”

Defects by design: Quantum nanophotonics in emerging materials

“…Their article is a detailed guide for the design and operation of such microscopes, which have applications in biology, materials science, and geoscience. Meanwhile, Oberg et al [5] present an intriguing theoretical proposal to transfer an electron with a quantum-coherent spin state from one NV center to another one in a diamond quantum wire via stimulated Raman adiabatic passage. This method could lead to a scalable architecture for quantum computers based on NV centers or other quantum defects.…”