S. K. Dutta

Effects of static and random magnetic fields on atoms in a gray optical lattice

We study magnetic field-induced modifications of the well-to-well tunneling behavior of atoms in a one-dimensional grey optical lattice. Measurements of the tunneling frequency as a function of the applied magnetic field reveal several tunneling resonances. We further show that the tunneling signal can be suppressed by randomly varying the symmetry of the potential wells. The tunneling is suppressed most effectively if the autocorrelation time of the lattice-well variation is on the order of the tunneling time. Experimental and theoretical results are in good agreement.

Long-lived states in cold Rydberg gases

Summary form only given. Laser-cooled atoms can be excited into Rydberg states to study Rydberg gases at high densities and low atomic velocities. Dense clouds of such atoms undergo virtually complete ionization when their density exceeds a critical value dependent on the principal quantum number n. We report a new regime in which the excited Rydberg population spontaneously evolves into long-lived high-l states, the lifetimes of which exceed the natural lifetimes of the initially excited Rydberg levels by two orders of magnitude. /sup 87/Rb atoms are collected and cooled to 50 /spl mu/K in a magneto optical trap (MOT), which is periodically turned off for 50 ms. 1 ms after the shutdown of the MOT the Rydberg atoms are created via a two-step excitation process using a 5 /spl mu/s long diode laser pulse.

Ponderomotive optical lattices: a method for trapping Rydberg atoms

Summary form only given. Cooling and trapping in atomic systems have ushered in a revolution in the fields of opto-mechanical control, high precision spectroscopy, quantum electrodynamics and quantum information; to date, however, these advances have been restricted almost exclusively to near-ground state atoms. Highly excited atoms, or Rydberg atoms, have been explored for decades as testing grounds for quantum mechanics, quantum chaos, wavepacket manipulation and, more recently, quantum computing. Though the cooling of Rydberg atoms has been proposed and the generation of cold Rydberg atoms from cold ground state atoms has been achieved, the ability to trap cold Rydberg atoms remains an important and unaddressed milestone. We present a method to trap Rydberg atoms in any electronic state based on the weakly-bound nature of the Rydberg electron.