Wider research context:
Non-equilibrium dynamics and relaxation is central to many of the most fundamental questions in quantum physics. Significant progress was made for weakly interacting systems, and for discrete lattice settings, but there are very few experimental investigations in the strongly interacting regime. Here we propose a set of experiments to look at non-equilibrium evolution and relaxation in strongly interacting 1d systems of Bosons, Fermions and in the BEC-BCS cross over.
Objectives
We focus on two main objectives exploring non-equilibrium evolution and relaxation in the strongly interacting regime and the BEC-BCS crossover: (1) Experimental test of the recently developed Generalized Hydrodynamics (GHD), a new method to describe dynamics in 1d systems. We will investigate if GHD can be extended towards very strong interactions, the BEC BCS Cross over and to 1d Fermions. (2) Nonequilibrium evolution of 1d quantum systems in the whole range from strongly interacting Bosons through the BEC-BCSS cross over deep into 1d- Fermion systems.
Methods
Experiments will be conducted with strongly interacting quantum gas of 6-Li fermions and 6-Li2 bosonic molecules in a single layer of 1d optical lattice traps. The 1d systems will be individually probed (1) in situ through the evolution of density and momentum (rapidity); and (2) the evolution of coherences and the order parameter by interference and correlations. Splitting a single 1d system into double well potentials enables matter wave interference. Single atom sensitive florescence imaging will be used to probe at the level of single systems, and to realize correlation measurements and spatially resolved detection of order parameter giving insight into superfluid phases.
Innovation
Strong suppression of inelastic processes for 6Li2 molecules offers a unique window to extend nonequilibrium studies into the strongly interacting regime and to long evolution times. Tunability of the interactions using Feshbach resonances enables to explore a large variety of systems ranging from strongly interacting bosons to Tonks gas (fermionized bosons), and through the BEC-BCS crossover to superfluid fermions.
We will develop and implement methods to probe the order parameter of superfluid Fermi gas through interference and correlation.
Our proposed setup has the unique advantages:
- Directly probing single systems of 1d gases mitigating effects of ensemble averaging.
- Highly sensitive fluorescence imaging allows quantum limited measurement and detailed studies of (high order) correlations in density and phase.
- Significantly enhance the statistics by parallel experimental realizations in an array of 1d-traps.
