Atoms Trained

Laser Trapping and Cooling of Atoms

Laser cooling methods have made a dramatic impact on physics, resulting in three Nobel Prizes. Laser-cooled atoms are used for Bose-Einstein condensation, atomic clocks, ultra-cold collisions, and quantum information processing. Some of the contributions of Prof. Walker and the Atom Trainers are:

  • First diode-laser atom trap (Cs), light-intensity dependence of ultracold collisions
  • Discovery and explanation of light-induced collective phenomena in traps
  • First Magneto-optical Trap of Rb atoms.
  • Spin-polarized trapping of atoms.
  • First observation of Landau-Zener excitation in ultracold collisions. 
  • First use of trapped atoms as target for scattering experiments. 
  • Demonstration of funnel-loaded trap 
  • Spatial heterodyne imaging of atoms– 1/1000 photon per atom.
  • New concepts in single atom, single photon sources 
  • Record trapped-atom densities in Holographic Atom Trap
  • High fidelity quantum manipulation of atoms in an array of traps
  • Coherent Rabi Oscillations With Rydberg Atoms 
  • Rydberg Blockade of single atoms 10 μm apart.
  • First Neutral Atom CNOT gate 
  • Deterministic entanglement of neutral atom pairs 
  • Review article on quantum information with Rydberg atoms 
  • Production of Atomic Fock states using Rydberg blockade 
  • Coherence and blockade of W-states of ensembles 
  • Non-destructive readout of atomic qubits 
  • Continuously tunable Rydberg RF detector 

Spin-polarized atoms

Optical Pumping is an important method for producing spin polarized samples of atoms and nuclei for magnetic-resonance imaging, polarized ion beams for accelerators, targets for scattering experiments, and high sensitivity detectors such as magnetometers. Major contributions include:

  • Origin of spin-rotation interaction in alkali–noble-gas molecules 
  • Reliable estimates of spin-exchange and spin-relaxation rates 
  • Prediction (subsequently experimentally confirmed by groups at Argonne and Erlangen) of
    nuclear polarization of H and D atoms by spin-exchange at high fields. 
  • Discovery of alkali-alkali spin-relaxation due to triplet dimer formation 
  • Invention of new narrow-band high power laser sources 
  • Discovery of Xe-Xe molecular spin relaxation
  • State-of-the-art measurements of spin-relaxation rates. 
  • Hybrid spin-exchange optical pumping.
  • Discovery of ‘X-factor’ polarization limits of Rb-3He.
  • Major review article on spin-exchange optical pumping. 
  • Novel method for atomic magnetometry 
  • Discovery of angular momentum selection rule violation 
  • First detection of fetal magnetocardiography with an atomic magnetometer 
  • Xe comagnetometry search for axion-like particles 
  • Demonstration of synchronous spin-exchange optical pumping 
  • High performance co-magnetometry using Xe isotopes