RF-free driving of nuclear spins with color centers in silicon carbide

TL;DR

This paper demonstrates RF-free coherent control of nuclear spins in silicon carbide using microwave pulses, simplifying quantum device operation and reducing power consumption.

Contribution

It introduces a method to control nuclear spins via microwave pulses alone, eliminating the need for RF fields in silicon carbide color centers.

Findings

Achieved 89% two-qubit tomography fidelity.

Demonstrated nearly T1-limited nuclear coherence times.

Controlled nuclear spins using hyperfine-enhanced effects with MW pulses.

Abstract

Color centers that enable nuclear-spin control without RF fields offer a powerful route towards simplified and scalable quantum devices. Such capabilities are especially valuable for quantum sensing and computing platforms that already find applications in biology, materials science, and geophysics. A key challenge is the coherent manipulation of nearby nuclear spins, which serve as quantum memories and auxiliary qubits but conventionally require additional high-power RF fields which increase the experimental complexity and overall power consumption. Finding systems where both electron and nuclear spins can be controlled using a single MW source is therefore highly desirable. Here, using a modified divacancy center in silicon carbide, we show that coherent control of a coupled nuclear spin is possible without any RF fields. Instead, MW pulses driving the electron spin also manipulate the nuclear spin through hyperfineenhanced effects, activated by a precisely tilted external magnetic field. We demonstrate high-fidelity nuclear-spin control, achieving 89% two-qubit tomography fidelity and nearly T1-limited nuclear coherence times. This approach offers a simplified and scalable route for future quantum applications.