Micro-Electromagnets for Free Particle Manipulation

Chungsok Lee

Marija Drndić, C. S. Lee, R. M. Westervelt

Marija Drndić, Kent S. Johnson, Joseph H. Thywissen +2 more

Micro-electromagnets for atom manipulation have been constructed, including magnetic mirrors (serpentine patterns) and traps (circular patterns). They consist of planar micron-scale Au wires on sapphire substrates fabricated using lithography and electroplating. At liquid nitrogen or helium temperatures in vacuum the wires support currents of several amperes with current density ∼108 A/cm2 and power dissipation ∼10 kW/cm2, and they produce magnetic fields to 0.3 T and gradients to 103 T/cm. The micro-electromagnet mirror was used to deflect a beam of metastable helium atoms at grazing angles ∼0.5 mrad.

Timir Datta, Raphael Tsu

The new concept of quantum wave-impedance (QWI), Z is introduced to answer the question whether there is impedance to a Schrodinger wave. Z will be an analogue of Maxwell's free space impedance (376.7 ohm) for electromagnetic waves. We show, for free particle wave function, the value of Z is in general not zero and purely real (resistive). As in quantum hall (QHE), Z can be expressed in terms of the fine structure constant, the electromagnetic permittivity and permeability of free space. Z is a determinant of the partitioning and flow of charge and energy transported by the quantum system. The scale factor of Z is about 12.9 kilo-ohms (per spin), so the corresponding wave conductance G is (77.5 micro-mho, per spin) double the unit of Landaur conductance. As functions of the quantum numbers (l,m,n) Z shows, peaks, valleys and plateaus; also as in QHE, both integer and fractional steps may be obtained. In microwave and optical technology, conventional impedance is an essential parameter. The quantum impedance defined here will be no exception in future technology.

Jeffrey Heward, Mark Edwards, Charles W. Clark

Masaaki Ashida, Shota Sasaki, Jun Naoi +5 more

Magnetic trapping and optical manipulation of micro-particles are combined in superfluid helium. Irradiation of pulsed light to a magnetically trapped superconducting particle causes simple damped oscillation of the particle. The analysis of the trajectory gives rise to the estimation of viscosity of the superfluid helium along with some properties of the trapped particle.