Artificial electromagnetism for neutral atoms: Escher staircase and Laughlin liquids

We show how lasers may create fields which couple to neutral atoms in the same way that the electromagnetic fields couple to charged particles. These fields are needed for using neutral atoms as an analog quantum computer for simulating the properties of many-body systems of charged particles. They allow for seemingly paradoxical geometries, such as a ring where atoms continuously reduce their potential energy while moving in a closed path. We propose neutral atom experiments which probe quantum Hall effects and the interplay between magnetic fields and periodic potentials.Comment: 4 pages, 1 color figure, RevTeX 4; v2 Revised introduction, additional reference

Superfluidity and Swallowtails; Hysteretic Behavior in Bose Condensates

We present a theory of hysteretic phenomena in Bose gases, using superfluidity in one dimensional rings and in optical lattices as primary examples. Through this study we are able to give a physical interpretation of swallowtail loops recently found by many authors in the mean-field energy structure of trapped atomic gases. These loops are a generic sign of hysteresis, and in the present context are an indication of superfluidity. We have also calculated the rate of decay of metastable current carrying states due to quantum fluctuations.Comment: 32 pages, 15 figures, REVTeX4; v2: added references, corrected fonts in figure

Heating from Continuous Number Density Measurements in Optical Lattices

We explore the effects of continuous number density measurement on atoms in an optical lattice. By integrating a master equation for quantum observables, we calculate how single particle correlations decay. We consider weakly- and strongly- interacting bosons and noninteracting fermions. Even in the Mott regime, such measurements destroy correlations and increase the average energy, as long as some hopping is allowed. We explore the role of spatial resolution, and find that the heating rate is proportional to the amount of information gained from such measurements.Comment: 10 pages, 4 figure

Magnetic field dependence of Raman coupling in Alkali atoms

We calculate the magnetic field dependence of Rabi rates for two-photon optical Raman processes in alkali atoms. Due to a decoupling of the nuclear and electronic spins, these rates fall with increasing field. At the typical magnetic fields of alkali atom Feshbach resonances (B\sim 200G-1200G), the Raman rates have the same order of magnitude as their zero field values, suggesting one can combine Raman-induced gauge fields/spin-orbital coupling with strong Feshbach-induced interactions. The exception is $^6$Li, where there is a factor of 7 suppression in the Raman coupling, compared to its already small zero-field value.Comment: 5 pages, 4 figure