arXiv subjects

Per-Kristian Rekdal

Publications and source records attributed to Per-Kristian Rekdal.

2 recordsLinked to original sources

arXiv2005

Atomic spin decoherence near conducting and superconducting films

We derive scaling laws for the spin decoherence of neutral atoms trapped near conducting and superconducting plane surfaces. A new result for thin films sheds light on the measurement of Y.J. Lin, I. Teper, C. Chin, and V. Vuletić [Phys. Rev. Lett. \textbf{92}, 050404 (2004)]. Our calculation is based on a quantum-theoretical treatment of electromagnetic radiation near metallic bodies [P.K. Rekdal, S. Scheel, P.L. Knight, and E.A. Hinds, Phys. Rev. A \textbf{70}, 013811 (2004)]. We show that there is a critical atom-surface distance that maximizes the spin relaxation rate and we show how this depends on the skin depth and thickness of the metal surface. In the light of this impedance-matching effect we discuss the spin relaxation to be expected above a thin superconducting niobium layer.

quant-ph↗

arXiv2004

Thermal spin flips in atom chips

We derive the spontaneous and thermal spin-flip rates for a neutral two-level ultra-cold atom that is coupled to a magnetic field. We apply this theory to an atom in the vicinity of a 2-layer cylindrical absorbing dielectric body surrounded by an unbounded homogeneous medium. An analytical expression is obtained for the spontaneous and thermal spin-flip rate in this particular geometry. The corresponding lifetime is then computed numerically. We compare these theoretical lifetimes to those measured by Jones et al. [M.P.A. Jones, C.J. Vale, D. Sahagun, B.V. Hall, and E.A. Hinds, Phys. Rev. Lett. {\bf 91}, 080401 (2003)]. We investigate how the lifetime depends on the materials (skin depths) of the cylindrical body. We also show how scaling of the dimensions of the cylindrical body affects the lifetime when (i) the distance from the wire to the atom is fixed and (ii) when the distance from the wire to the atom is scaled.

quant-ph↗