Field-dependent superradiant quantum phase transition of molecular magnets in microwave cavities

TL;DR

This paper predicts a tunable superradiant quantum phase transition in molecular magnets within microwave cavities, characterized by a sudden increase in emitted radiation and electric dipole moment, detectable with current technology.

Contribution

It introduces a model showing a magnetic-field-tunable superradiant phase transition in molecular magnets coupled to microwave cavities, distinct from standard two-level systems.

Findings

Superradiant transition occurs at a critical coupling strength.

Transition can be tuned by an external magnetic field.

The transition involves a measurable electric dipole moment.

Abstract

We find a superradiant quantum phase transition in the model of triangular molecular magnets coupled to the electric component of a microwave cavity field. The transition occurs when the coupling strength exceeds a critical value which, in sharp contrast to the standard two-level emitters, can be tuned by an external magnetic field. In addition to emitted radiation, the molecules develop an in-plane electric dipole moment at the transition. We estimate that the transition can be detected in state of the art microwave strip-line cavities containing $10^{15}$ molecules.