Long range magnetic dipole-dipole interaction mediated by a superconductor

TL;DR

This paper proposes a theoretical method using superconducting nanostructures to enhance and control magnetic dipole-dipole interactions between spin qubits, potentially improving solid-state quantum computing.

Contribution

It introduces a novel approach to mediate long-range qubit coupling via superconducting structures, with detailed analytical and simulation analysis.

Findings

Superconducting apertures channel magnetic flux effectively.

Enhanced dipole-dipole interaction over longer distances.

Potential for engineered controllable spin systems.

Abstract

Quantum computation and simulation requires strong coherent coupling between qubits, which may be spatially separated. Achieving this coupling for solid-state based spin qubits is a long-standing challenge. Here we theoretically investigate a method for achieving such coupling, based on superconducting nano-structures designed to channel the magnetic flux created by the qubits. We detail semi-classical analytical calculations and simulations of the magnetic field created by a magnetic dipole, depicting the spin qubit, positioned directly below nanofabricated apertures in a superconducting layer. We show that such structures could channel the magnetic flux, enhancing the dipole-dipole interaction between spin qubits and changing its scaling with distance, thus potentially paving the way for controllably engineering an interacting spin system.