A quantum many-body spin system in an optical lattice clock

TL;DR

This paper demonstrates the use of ultracold ${}^{87}$Sr atoms in an optical lattice clock to study strongly interacting quantum many-body effects, revealing complex dynamics and correlations in a highly coherent system.

Contribution

It introduces a new platform for exploring quantum many-body physics using optical lattice clocks with precisely controlled interactions and coherence.

Findings

Observation of many-body dynamics and beyond-mean-field effects

Derivation of a Hamiltonian explaining distorted lineshapes and spin noise

Detection of density-dependent frequency shifts and coherence decay

Abstract

Strongly interacting quantum many-body systems are fundamentally compelling and ubiquitous in science. However, their complexity generally prevents exact solutions of their dynamics. Precisely engineered ultracold atomic gases are emerging as a powerful tool to unravel these challenging physical problems. Here we present a new laboratory for the study of many-body effects: strongly interacting two-level systems formed by the clock states in ${}^{87}$Sr, which are used to realize a neutral atom optical clock that performs at the highest level of optical-atomic coherence and with precision near the limit set by quantum fluctuations. Our measurements of the collective spin evolution reveal signatures of many-body dynamics, including beyond-mean-field effects. We derive a many-body Hamiltonian that describes the experimental observation of severely distorted lineshapes, atomic spin coherence decay, density-dependent frequency shifts, and correlated quantum spin noise. These investigations open the door to exploring quantum many-body effects and entanglement in quantum systems with optical energy splittings, using highly coherent and precisely controlled optical lattice clocks.