Abstract
Nuclear spins show long coherence times and are well isolated from the environment, which are properties making them promising for quantum information applications. Here, we present a method for nuclear spin readout by probing the transmission of a microwave resonator. We consider a single electron in a silicon quantum dot-donor device interacting with a microwave resonator via the electric dipole coupling and subjected to a homogeneous magnetic field and a transverse magnetic field gradient. In our scenario, the electron spin interacts with a $^{31}\mathrm{P}$ defect nuclear spin via the hyperfine interaction. We theoretically investigate the influence of the P nuclear spin state on the microwave transmission through the cavity and show that nuclear spin readout is feasible with current state-of-the-art devices. Moreover, we identify optimal readout points with strong signal contrast to facilitate the experimental implementation of nuclear spin readout. Furthermore, we investigate the potential for achieving coherent excitation exchange between a nuclear spin qubit and cavity photons.
Highlights
Nuclear spins are promising candidates for quantum information applications due to their long coherence times [1,2] that can even be observed up to room temperature [3]
We have investigated a system composed of a donor nuclear spin coupled to the spin of a single electron in a quantum dot (QD)-donor architecture via the hyperfine interaction
The electron is subject to a homogeneous magnetic field and a magnetic field gradient perpendicular to the homogeneous component, while it is dipole coupled to a microwave resonator
Summary
Nuclear spins are promising candidates for quantum information applications due to their long coherence times [1,2] that can even be observed up to room temperature [3]. The same mechanism can be used to realize a flopping-mode spin qubit with full electrical spin control via electric dipole spin resonance (EDSR) [34,35] In this system, a longitudinal magnetic field gradient leads to a shift of the phase and amplitude response of the cavity transmission depending on the strength of the field gradient [35]. Our detailed discussion of the expected characteristics in the cavity transmission indicates that the observable signature of the strong electron spin-photon coupling [20,21] is significantly altered by the state of the nuclear spin and could be used for nuclear spin state readout This prediction is verified by calculating the cavity transmission using input-output theory.
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