Abstract
We propose a novel optical and electrical hybrid scheme for the measurement of nuclear spin qubits in silicon. By combining the environmental insensitivity of the integer quantum Hall effect with the optically distinguishable hyperfine states of phosphorus impurities in silicon, our system can offer both nuclear spin measurement and robustness against environmental defects. 31P donor spins in isotopically purified 28Si are often discussed as very promising quantum memory qubits due to their extremely long decoherence times, and our proposed device offers an effective implementation for such a quantum memory system.
Highlights
Semiconductor qubit implementations hold many advantages over other qubit systems, such as long decoherence times and a wealth of current industry experience
Vqpc is the potential term for the quantum point contact (QPC) channel, which we have modeled as a parabolic potential along the x-axis, which is perpendicular to the direction of the edge state propagation
If single-shot measurement is achieved, by optically pumping on a pair of transitions beginning in the same electron spin state but opposite nuclear spin state we can a perform deterministic measurement of the donor-bound-electron spin, but in this case it is a destructive measurement
Summary
Semiconductor qubit implementations hold many advantages over other qubit systems, such as long decoherence times and a wealth of current industry experience. While we do not want the measurement to be sensitive to most defects in the device, we need the device to interact with one particular defect, a P donor which is located just below the inversion layer in the center of the Hall bar This donor could be implanted using single ion implantation through the optical aperture in the global gate [19], or be placed via registered STM techniques [20]. The neutral donor can bind a free exciton, creating the 4-quasi-particle complex comprised of two electrons coupled in a spin singlet, a hole, and the nucleus This metastable state can be resonantly excited with the laser, and will either decay optically or, three orders of magnitude more often, non-radiatively via Auger recombination, leaving the donor ionized. Either method is a deterministic quantum non-demolition measurement of the single donor nuclear spin
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