Spin amplification in realistic systems

TL;DR

This paper demonstrates a rapid, optimal control-based method for spin amplification in realistic systems, enabling faster and more robust excitation enhancement even amid decoherence and inhomogeneity.

Contribution

It introduces a novel fast spin amplification protocol using optimal control, applicable to superconducting and Rydberg atom systems, surpassing previous methods in speed.

Findings

Achieves spin amplification in times comparable to intrinsic interaction timescales.

Effective even with significant decoherence and inhomogeneity.

Applicable to superconducting and Rydberg atom systems.

Abstract

Spin amplification is the process that ideally increases the number of excited spins when one of them is excited initially. We show that by applying optimal control techniques to design classical drive pulse shapes, spin amplification can be achieved in a previously unexplored fast regime, with amplification times comparable to the intrinsic interaction timescale. This is an order of magnitude faster than the previous protocols and makes spin amplification possible even with significant decoherence and inhomogeneity in the spin system. The initial spin excitation can be delocalized over the entire ensemble, which is a more typical situation when a photon is collectively absorbed by the spins. We focus on the superconducting persistent-current artificial atoms and the Rydberg atoms as spins.