Coherent tunneling of lithium defect pairs in KCl crystals

¹Institut für Angewandte Physik, Universität Heidelberg, Albert-Überle-Str. 3-5, D-69120 Heidelberg, Germany
²Institut Laue-Langevin, B.P.156, 38042 Grenoble Cedex 9, France
³Department of Physics, University of Utah, Salt Lake City, USA

Received 8 August 1996, final version 27 January 1997, accepted 27 January 1997

Keywords: Tunneling states; Rotary echoes; Isotope effect.

Effective Hamiltonian for scalar theories in the Gaussian approximation

¹Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, D-69120 Heidelberg, Germany

Received 22 October 1996, revised version 13 January 1997, accepted 31 January 1997

Keywords: Hamiltonian field theory; Variational approach; Spontaneous symmetry breaking

Rapid evaluation of oscillating lattice sums

¹Hahn-Meitner-Institut, Glienicker Str. 100, D-14109 Berlin, Germany, and Department of Condensed Matter Physics, Royal Institut of Technology, S-100044 Stockholm, Sweden

Received 25 September 1996, revised version 17 February 1997, accepted 21 February 1997

Keywords: Lattice Summation; Dipole Interaction; Demagnetizing energy

Spin depolarization of spreading and propagating wave packets

¹Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany

Received 7 November 1996, accepted 31 January 1997

Keywords: Spreading and propagating of wave packets; Spin relaxation; Disorderd Larmor frequencies