Realization of fractional Fermi seas

TL;DR

This paper reports the experimental creation of fractional Fermi seas in a one-dimensional Bose gas, revealing exotic quantum states with fractional momentum occupancies and Friedel oscillations, advancing understanding of quantum statistics.

Contribution

First experimental realization of fractional Fermi seas in a Bose gas, demonstrating stable exotic quantum states with fractional occupancy and Friedel oscillations.

Findings

Observation of Friedel oscillations as signatures of FFS

Preparation of excited, stable Bose-gas states with fractional occupancies

Potential implications for quantum thermodynamics and quantum technologies

Abstract

The Pauli exclusion principle is a cornerstone of quantum physics: it governs the structure of matter. Extensions of this principle, such as Haldane's generalized exclusion statistics, predict the existence of exotic quantum states characterized by fractional Fermi seas (FFS), i.e. momentum distributions with uniform but fractional occupancies. Here, we report the experimental realization of fractional Fermi seas in an excited one-dimensional Bose gas prepared through ramping cycles in the interaction strength. The resulting excited yet stable Bose-gas states exhibit Friedel oscillations, smoking-gun signatures of the underlying FFS. The stabilization of these states offers an opportunity to deepen our understanding of quantum thermodynamics in the presence of exotic statistics and paves the way for applications in quantum information and sensing.