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Circuit Quantum Electrodynamics with a Spin Qubit
K. D. Petersson, L. W. McFaul, M. D. Schroer, M. Jung, J. M. Taylor, A. A. Houck, J. R. Petta
TL;DR
Long-range interactions are important for scalable spin-based quantum computing, but conventional spin–cavity coupling is weak. This paper couples an InAs nanowire spin-orbit qubit to a superconducting cavity, demonstrating time-resolved spin dynamics and an estimated spin lifetime of about 1 µs.
Problem
Scalable spin-based quantum computing requires long-range qubit interactions, while weak magnetic coupling provides insufficient interaction strength.
Method
The authors use spin-orbit coupling to connect a single-electron spin-orbit qubit’s electric field to a high-quality-factor superconducting cavity.
Results
Time-resolved Rabi oscillations were demonstrated in the spin-orbit qubit, and its spin lifetime was estimated as T1 ∼1 µs.
Takeaways & Limitations
The hybrid quantum system demonstrates cavity-compatible coherent spin dynamics and enables measurement of the spin lifetime.
Takeaways & Limitations
A conventional cavity produces a spin-cavity vacuum Rabi frequency of only ∼10 Hz, described as far too weak for the intended coupling.
Abstract
from arXiv · showhide
Circuit quantum electrodynamics allows spatially separated superconducting qubits to interact via a "quantum bus", enabling two-qubit entanglement and the implementation of simple quantum algorithms. We combine the circuit quantum electrodynamics architecture with spin qubits by coupling an InAs nanowire double quantum dot to a superconducting cavity. We drive single spin rotations using electric dipole spin resonance and demonstrate that photons trapped in the cavity are sensitive to single spin dynamics. The hybrid quantum system allows measurements of the spin lifetime and the observation of coherent spin rotations. Our results demonstrate that a spin-cavity coupling strength of 1 MHz is feasible.