Fermi gases
Cavity quantum electrodynamics with strongly correlated matter
Our machine combines a high finesse optical cavity, where single or few photons interact strongly with atoms, and a Fermi gas of lithium atoms with tunable interactions.
Density-wave ordering in a unitary Fermi gas with photon mediated interactions
We have realized a Fermi gas featuring both strong, tunable contact interactions and photon-mediated, spatially structured long-range interactions in a transversely driven high-finesse optical cavity. Above a critical long-range interaction strength, DW order is stabilized in the system, which we identify via its superradiant light scattering properties. We quantitatively measure the variation of the onset of DW order as the contact interaction is varied across the BCS-BEC crossover, in qualitative agreement with a mean-field theory. The atomic DW susceptibility varies over an order of magnitude upon tuning the strength and the sign of the long-range interactions below the self-ordering threshold, demonstrating independent and simultaneous control over the contact and long-range interactions.Â
Read the paper in Nature
Optomechanical Response of a Strongly Interacting Fermi Gas
We study a Fermi gas with strong, tunable interactions dispersively coupled to a high-finesse cavity. Upon probing the system along the cavity axis, we observe a strong optomechanical Kerr nonlinearity originating from the density response of the gas to the intracavity field. Measuring the non-linearity as a function of interaction strength, we extract the zero-frequency density response function of the Fermi gas, and find an increase by a factor of two from the Bardeen-Cooper-Schrieffer to the Bose-Einstein condensate regime, in agreement with a theory based on operator-product expansion.
Read the paper in Phys. Rev. Research
Universal pair-polaritons in a strongly interacting Fermi gas
We have observed strong light-matter coupling on molecular transitions. This connects the optical spectrum of the coupled atom-cavity system to many-body physics in the strongly interacting Fermi gas, bridging over two orders of magnitudes energy differences. We also used this feature to realize a weakly-destructive, repeated measurement of the pair correlations in a Fermi gas.
Read the paper in Nature
Cavity-assisted preparation and detection of a unitary Fermi gas
We describe both the preparation scheme for cold Fermions in the cavity and show that the cavity can be used to track the population in the cloud in real time in a weakly destructive fashion.
Read the paper in New Journal of Physics
Strongly correlated Fermions strongly coupled to light
We have produced the first Fermi gas in strong coupling with light in a high finesse cavity.
Read the paper in Nature Communications
Compact bulk-machined electromagnets for quantum gas experiments
Our customizable, bulk machined coil design for quantum gases experiments
Read the paper in SciPost Physics
Universal noise in continuous transport measurements of interacting fermions
The theory of continous measurement of atom nummber and currents in strongly interacting Fermi gas using a high-finesse cavity
Read the paper in Physical Review A