We calculate the dynamics of one- and two-body correlation functions in a homogeneous Bose gas at zero temperature following a sudden change in the interaction strength, in the continuum and in a lattice. By choosing suitable examples, we highlight features in the correlation functions that emerge due to the interactions and the band structure. We find that interactions dramatically change the way correlations build up and subsequently decay following a quench.

We calculate the magnetic-field dependence of Rabi rates for two-photon optical Raman processes in alkali-metal atoms. Due to a decoupling of the nuclear and electronic spins, these rates fall with increasing field. At the typical magnetic fields of alkali-metal-atom Feshbach resonances (B∼200-1200 G), the Raman rates have the same order of magnitude as their zero-field values, suggesting one can combine Raman-induced gauge fields or spin-orbital coupling with strong Feshbach-induced interactions.

We use a high-temperature expansion to explore spin correlations around a single hole in a two-dimensional lattice filled with a hard-core two-component bose gas. We find that the spins around the hole develop ferromagnetic order and quantify the degree of polarization at temperatures of the order of the hopping energy, finding a measurably nonzero polarization. We also discuss the effect of fixing the overall magnetization of the system for finite-sized systems. © 2013 American Physical Society.

Motivated by recent observations, we study the stability of a Bose-Einstein condensate within a spin-dependent honeycomb lattice towards forming a "twisted superfluid" state. Our exhaustive numerical search fails to find this phase, pointing to possible non-mean-field physics. © 2013 American Physical Society.

The recently discovered shear modulus anomaly in solid 4He bears a strong similarity to the phenomenon of supersolidity in solid 4He and can lead to the period shift and dissipative signals in torsional oscillator experiments that are nearly identical to the classic NCRI signals observed by Kim and Chan. In the experiments described here, we attempt to isolate the effects of these two phenomena on the resonance periods of torsion oscillators. We have constructed a triple compound oscillator with distinct normal modes.

We theoretically study trapped one-dimensional Fermi gases in the presence of spin-orbit coupling induced by Raman lasers. The gas changes from a conventional (nontopological) superfluid to a topological superfluid as one increases the intensity of the Raman lasers above a critical chemical-potential-dependent value. Solving the Bogoliubov-de Gennes equations self-consistently, we calculate the density of states in real and momentum space at finite temperatures.

The torsional oscillator is the chief instrument for investigating supersolidity in solid 4He. These oscillators can be sensitive to the elastic properties of the solid helium, which show anomalies over the same range of temperature in which the supersolid phenomenon appears. In this report we present a detailed study of the influence of the elastic properties of the solid on the periods of torsional oscillators for the various designs that have been commonly employed in supersolid measurements.

We study the vortex structures of a (pseudo)spin-1/2 Fermi gas experiencing a uniform effective magnetic field in an anisotropic trap that interpolates between quasi-one dimensional (1D) and quasi-two dimensional (2D). At a fixed chemical potential, reducing the anisotropy (or equivalently increasing the attractive interactions or increasing the magnetic field) leads to instabilities towards pair density waves and vortex lattices. Reducing the chemical potential stabilizes the system. We calculate the phase diagram and explore the density and pair density.

By combining experiments and numerical simulations, we investigate the redistribution of quasimomentum in a gas of atoms trapped in an optical lattice when the lattice depth is rapidly reduced. We find that interactions lead to significant momentum redistribution on millisecond time scales, thereby invalidating previous assumptions regarding adiabaticity. Our results indicate band mapping is an inaccurate probe of the equilibrium quasimomentum distributions of interacting bosons in the single-band regime. © 2012 American Physical Society.

We report on a numerical experiment in which we use time-dependent potentials to braid non-Abelian quasiparticles. We consider lattice bosons in a uniform magnetic field within the fractional quantum Hall regime, where ν, the ratio of particles to flux quanta, is near 1/2, 1, or 3/2. We introduce time-dependent potentials which move quasiparticle excitations around one another, explicitly simulating a braiding operation which could implement part of a gate in a quantum computation.