Evolution of Fermion Pairing from Three to Two Dimensions

TL;DR

This study investigates how fermion pairing evolves from three to two dimensions in a strongly interacting Fermi gas, revealing dimensionality-dependent pairing gaps and confirming theoretical models in the 2D limit.

Contribution

It provides experimental insights into the dimensional crossover of fermion pairing and validates theoretical predictions in the 2D regime.

Findings

Opening of a pairing gap in RF spectra with decreasing dimensionality

Measured binding energies match two-body theoretical predictions

In 2D limit, data agrees with zero-temperature mean-field BEC-BCS theory

Abstract

We follow the evolution of fermion pairing in the dimensional crossover from 3D to 2D as a strongly interacting Fermi gas of $^6$Li atoms becomes confined to a stack of two-dimensional layers formed by a one-dimensional optical lattice. Decreasing the dimensionality leads to the opening of a gap in radio-frequency spectra, even on the BCS-side of a Feshbach resonance. The measured binding energy of fermion pairs closely follows the theoretical two-body binding energy and, in the 2D limit, the zero-temperature mean-field BEC-BCS theory.