Quantum Emulations of New Materials Using Ultracold Atoms
Abstract
During the grant period, we had major results in three different areas. (1) Strongly interacting Fermi gases. Since arbitrary mixtures of hyperfine states can be created using RF population transfer, we could extend our studies to imbalanced Fermi gases. A major highlight has been the exploration of the phase diagram of this system [1]. Using RF spectroscopy, we determined the pair size [2] and the gap parameter [3] of the superfluid.(2) A second area of activity was the development of a new method for thermometry [4]and for adiabatic cooling [5] using a two-component Mott insulator in a magnetic field gradient (spin gradient thermometry and spin gradient demagnetization cooling). (3) We characterized Fermi systems by observing fluctuations in the density and spin density.This method was applied to the ideal (non-interacting) Fermi gas [6], and to systems with attractive [7] and repulsive interactions [8]. For repulsive interactions, we ruled out that the simple Stoner model which predicts itinerant ferromagnetism for fermions with shortrange repulsion is incorrect, since the ferromagnetic phase transition is preempted by formation of fermions pairs.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 2014
- Accession Number
- AD1194509
Entities
People
- Wolfgang Ketterle
Organizations
- Massachusetts Institute of Technology