Coherent dynamics of a nuclear-spin-isomer superposition

TL;DR

This paper proposes a scheme to create and analyze a quantum superposition between nuclear-spin isomers in molecules, using an avoided crossing to induce strong coupling, thus advancing molecular quantum control.

Contribution

It introduces a novel method to generate nuclear-spin-isomer superpositions via avoided crossings, modeling the dynamics with a four-level Hamiltonian applicable to similar systems.

Findings

Successful modeling of coherent dynamics in nuclear-spin-isomer superpositions

Identification of regimes for strong coupling and coherence preservation

Potential for extending the approach to other molecular systems

Abstract

Preserving quantum coherence with the increase of a system's size and complexity is a major challenge. Molecules, with their diverse sizes and complexities and many degrees of freedom, are an excellent platform for studying the transition from quantum to classical behavior. While most quantum-control studies of molecules focus on vibrations and rotations, we focus here on creating a quantum superposition between two nuclear-spin isomers of the same molecule. We present a scheme that exploits an avoided crossing in the spectrum to create strong coupling between two uncoupled nuclear-spin-isomer states, hence creating an isomeric qubit. We model our scheme using a four-level Hamiltonian and explore the coherent dynamics in the different regimes and parameters of our system. Our four-level model and approach can be applied to other systems with a similar energy-level structure.