Rotational decoherence dynamics in ultracold molecules induced by a tunable spin environment: The Central Rotor Model

TL;DR

This paper introduces the central rotor model, describing how ultracold molecules' rotational wavepacket dynamics are influenced by a tunable nuclear spin environment, revealing rich decoherence behaviors sensitive to magnetic fields.

Contribution

It proposes a new system-environment model for molecular rotation coupled to a tunable spin bath, extending the central spin paradigm with richer dynamics and experimental relevance.

Findings

Rotational decoherence is highly sensitive to external magnetic fields.

Numerical simulations demonstrate environment-dependent rotational dynamics.

Ultracold molecular gases are suitable for experimental realization of the model.

Abstract

We show that quantum rotational wavepacket dynamics in molecules can be described by a new system-environment model, which consists of a rotational subsystem coupled to a magnetically tunable spin bath formed by the nuclear spins within the molecule. The central rotor model shares similarities with the paradigmatic central spin model, but features much richer rotational dynamics that is sensitive to the molecule's environment, which can be initiated and probed with short laser pulses used to control molecular orientation and alignment. We present numerical simulations of the nuclear-spin-bath-induced rotational decoherence dynamics of KRb molecules, which exhibit remarkable sensitivity to an external magnetic field. Our results show that ultracold molecular gases provide a natural platform for the experimental realization of the CRM.