Control of a qubit state by a soliton propagating through a Heisenberg spin chain

TL;DR

This paper shows how nonlinear magnetic solitons traveling through a Heisenberg spin chain can be used to coherently control the state of a nearby qubit, with potential applications in quantum information processing.

Contribution

It introduces a method to map the interaction between solitons and a qubit onto a two-level system Hamiltonian, enabling controlled qubit manipulation via soliton parameters.

Findings

Solitons can coherently control qubit states.

The Hamiltonian maps onto a two-level system with soliton-dependent matrix elements.

Different soliton types (bright and dark) influence the qubit differently.

Abstract

We demonstrate that nonlinear magnetic solitary excitations (solitons) traveling through a Heisenberg spin chain may be used as a robust tool capable of coherent control of the qubit's state. The physical problem is described by a Hamiltonian involving the interaction between the soliton and the qubit. We show that under certain conditions the generic Hamiltonian may be mapped on that of a qubit two-level system with matrix elements depending on the soliton parameters. We considered the action of a bright and a dark solitons depending on the driving nonlinear wave function. We considered a local interaction restricted the closest to the qubit spin in the chain. We computed the expressions of the physical quantities of interest for all cases and analyzed their behavior in some special limits.