Prospective of Zr$^{3+}$ ion as a THz atomic clock

TL;DR

This paper proposes a new THz atomic clock based on the transition in triply ionized zirconium (Zr IV), demonstrating its potential for precise frequency measurement and applications in quantum thermometry.

Contribution

It introduces the Zr IV transition as a feasible THz atomic clock and provides detailed analysis of systematic shifts affecting its accuracy.

Findings

Transition frequency is about 37.52 THz.

Estimated systematic shifts include blackbody radiation and Zeeman effects.

Proposed clock can be useful for quantum thermometry and frequency metrology.

Abstract

We demonstrate transition between the fine structure splitting of the ground state of triply ionized zirconium (Zr IV) is suitable for a terahertz (THz) atomic clock. Its transition frequency is about 37.52 THz and is mainly guided by the magnetic dipole (M1) transition and can be accessible by a readily available laser. We suggest to consider stable even isotopes of Zr and $M_J= \pm 1/2$ sublevels (i.e. $|4D_{3/2},M_J=\pm 1/2\rangle \rightarrow |4D_{5/2},M_J=\pm 1/2\rangle$ clock transition) for the experimental advantage. By performing necessary calculations, we have estimated possible systematics due to blackbody radiation, ac Stark, electric quadrupole and second-order Zeeman shifts along with shifts due to the second-order Doppler effects. The proposed THz atomic clock can be very useful in quantum thermometry and frequency metrology.