Condensed Matter Seminar, Cheng Chin, U of Chicago,“Ferromagnetic domains and roton excitations in a dilute Bose superfluid”

Mon, Nov 24, 2014, 1:15 pm to 2:30 pm
PCTS Seminar Room
We present a new scheme to engineer the energy-momentum dispersion of atoms in optical lattices. By hybridizing bands, we identify a novel quantum phase transition from the emergence of superfluid domains with ferromagnetic interactions. Bragg spectroscopy within one domain reveals the appearance of roton excitations, which strongly suppress superfluidity near the quantum critical point.