Dressed Qubits in Nuclear Spin Baths

TL;DR

This paper introduces a method to encode dressed qubits in quantum dots using electron and nuclear spins, leveraging hyperfine interactions for quantum logic and decoherence protection.

Contribution

It proposes a novel encoding scheme that transforms hyperfine and dipole interactions into logical operations, enhancing qubit coherence.

Findings

Hyperfine coupling acts as a logic gate.

Nuclear dipole interactions are harnessed for protection.

Effective nuclear Hamiltonian resembles a pairing Hamiltonian.

Abstract

We present a method to encode a \textit{dressed} qubit into the product state of an electron spin localized in quantum dot and its surrounding nuclear spins via a dressing transformation. In this scheme, the hyperfine coupling and a portion of nuclear dipole dipole interaction become logic gates, while they are the sources of decoherence in electron spin qubit proposals. We discuss errors and corrections for the dressed qubits. Interestingly, the effective Hamiltonian of nuclear spins is equivalent to a pairing Hamiltonian, which provides the microscopic mechanism to protect dressed qubits against decoherence.