Self-generated quantum gauge fields in arrays of Rydberg atoms

TL;DR

This paper explores how density-dependent quantum gauge fields emerge in Rydberg atom arrays, revealing their influence on ground-state phases, current vortices, and spontaneous gauge field generation beyond mean-field approximations.

Contribution

It introduces a theoretical model of dynamical quantum gauge fields in Rydberg atom systems, highlighting their effects on phase behavior and transport properties.

Findings

Formation of current vortices in density wave phases

Quantum gauge field persists without density interactions

Spontaneous gauge field generation at critical hopping strength

Abstract

As shown in recent experiments [V. Lienhard et al., Phys. Rev. X 10, 021031 (2020)], spin-orbit coupling in systems of Rydberg atoms can give rise to density-dependent Peierls Phases in second-order hoppings of Rydberg spin excitations and nearest-neighbor (NN) repulsion. We here study theoretically a one-dimensional zig-zag ladder system of such spin-orbit coupled Rydberg atoms at half filling. The second-order hopping is shown to be associated with an effective gauge field, which in mean-field approximation is static and homogeneous. Beyond the mean-field level the gauge potential attains a transverse quantum component whose amplitude is dynamical and linked to density modulations. We here study the effects of this to the possible ground-state phases of the system. In a phase where strong repulsion leads to a density wave, we find that as a consequence of the induced quantum gauge field a regular pattern of current vortices is formed. However also in the absence of density-density interactions the quantum gauge field attains a non-vanishing amplitude. Above a certain critical strength of the second-order hopping the energy gain due to gauge-field induced transport overcomes the energy cost from the associated build-up of density modulations leading to a spontaneous generation of the quantum gauge field.