Experimental Observation of the 2D-1D Dimensional Crossover in Strongly Interacting Ultracold Bosons

TL;DR

This study experimentally investigates the transition from two to one dimension in strongly interacting ultracold bosons, revealing how quantum correlations evolve during the dimensional crossover through precise momentum distribution measurements.

Contribution

It provides the first detailed experimental observation of the 2D-1D crossover in strongly interacting ultracold bosons, supported by ab-initio theoretical analysis.

Findings

Observation of a varying two-slope structure in the momentum distribution

Demonstration of dimensionality-dependent decay of one-body correlations

Insights into the interplay of dimensionality, interactions, and temperature in quantum regimes

Abstract

Dimensionality plays an essential role in determining the nature and properties of a physical system. For quantum systems the impact of interactions and fluctuations is enhanced in lower dimensions, leading to a great diversity of genuine quantum effects for reduced dimensionality. In most cases, the dimension is fixed to some integer value. Here, we experimentally probe the dimensional crossover from two to one dimension using strongly interacting ultracold bosons in variable lattice potentials and compare the data to ab-initio theory that takes into account non-homogeneous trapping and non-zero temperature. From a precise measurement of the momentum distribution we analyze the characteristic decay of the one-body correlation function in the two dimensionalities and then track how the decay is modified in the crossover. A varying two-slope structure is revealed, reflecting the fact that the particles see their dimensionality as being one or two depending on whether they are probed on short or long distances, respectively. Our observations demonstrate how quantum properties in the strongly-correlated regime evolve in the dimensional crossover as a result of the interplay between dimensionality, interactions, and temperature.