Quantum Sensing Using Atomic Clocks for Nuclear and Particle Physics

TL;DR

This paper discusses how atomic clocks and quantum sensors can be used for high-precision measurements to detect tiny energy shifts caused by external fields, aiding research in nuclear and particle physics.

Contribution

It reviews the application of atomic clocks as quantum sensors for detecting minute energy shifts relevant to fundamental physics, highlighting recent advancements and potential for new discoveries.

Findings

Atomic clocks achieve fractional uncertainties of 10^{-18} or lower.

Quantum sensors can detect tiny energy shifts from hypothetical fields.

Constraints on coupling constants have been established through atomic measurements.

Abstract

Technologies for manipulating single atoms have advanced drastically in the past decades. Due to their excellent controllability of internal states, atoms serve as one of the ideal platforms as quantum systems. One major research direction in atomic systems is the precise determination of physical quantities using atoms, which is included in the field of precision measurements. One of such precisely measured physical quantities is energy differences between two energy levels in atoms, which is symbolized by the remarkable fractional uncertainty of $10^{-18}$ or lower achieved in the state-of-the-art atomic clocks. Two-level systems in atoms are sensitive to various external fields and can, therefore, function as quantum sensors. The effect of these fields manifests as energy shifts in the two-level system. Traditionally, such shifts are induced by electric or magnetic fields, as recognized even before the advent of precision spectroscopy with lasers. With high-precision measurements, tiny energy shifts caused by hypothetical fields weakly coupled to ordinary matter or by small effects mediated by massive particles can be potentially detectable, which are conventionally dealt with in the field of nuclear and particle physics. In most cases, the atomic systems as quantum sensors have not been sensitive enough to detect such effects. Instead, experiments searching for these interactions have placed constraints on coupling constants, except in a few cases where effects are predicted by the Standard Model of particle physics. Nonetheless, measurements and searches for these effects in atomic systems have led to the emergence of a new field of physics.