Floquet-Enhanced Spin Swaps

TL;DR

This paper demonstrates how leveraging interactions and disorder in multi-qubit systems, inspired by discrete time crystal physics, can significantly enhance the fidelity of spin swap operations in quantum-dot spin qubits, with implications for quantum information processing.

Contribution

It introduces a novel method using time crystal physics to improve spin swap operations in semiconductor quantum-dot spins, revealing the stabilizing role of interactions and disorder.

Findings

Enhanced swap fidelity by up to an order of magnitude.

Confirmation of effective Ising interactions between qubits.

Potential for stabilizing quantum operations using non-equilibrium phenomena.

Abstract

The transfer of information between quantum systems is essential for quantum communication and computation. In quantum computers, high connectivity between qubits can improve the efficiency of algorithms, assist in error correction, and enable high-fidelity readout. However, as with all quantum gates, operations to transfer information between qubits can suffer from errors associated with spurious interactions and disorder between qubits, among other things. Here, we harness interactions and disorder between qubits to improve a swap operation for spin eigenstates in semiconductor gate-defined quantum-dot spins. We use a system of four electron spins, which we configure as two exchange-coupled singlet-triplet qubits. Our approach, which relies on the physics underlying discrete time crystals, enhances the quality factor of spin-eigenstate swaps by up to an order of magnitude. Our results show how interactions and disorder in multi-qubit systems can stabilize non-trivial quantum operations and suggest potential uses for non-equilibrium quantum phenomena, like time crystals, in quantum information processing applications. Our results also confirm the long-predicted emergence of effective Ising interactions between exchange-coupled singlet-triplet qubits.