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J L Birman

Publications and source records attributed to J L Birman.

4 recordsLinked to original sources
PubMed2002

Report of a subcommittee on the nomenclature of n-dimensional crystallography. II. Symbols for arithmetic crystal classes, Bravais classes and space groups.

The Second Report of the Subcommittee on the Nomenclature of n-Dimensional Crystallography recommends specific symbols for R-irreducible groups in 4 and higher dimensions (nD), for centrings, for Bravais classes, for arithmetic crystal classes and for space groups (space-group types). The relation with higher-dimensional crystallographic groups used for the description of aperiodic crystals is briefly discussed. The Introduction discusses the general definitions used in the Report.

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PubMed2000

Implications of SU(2) symmetry on the dynamics of population difference in the two-component atomic vapor.

We present an exact many-body solution for the dynamics of the population difference N2-N1 induced by an rf field in the two-component atomic cloud characterized by equal scattering lengths. We show that no intrinsic decoherence occurs for N2-N1, provided that the exact intrinsic SU(2) symmetry holds. Decoherence for N2-N1 arises when deviations from the symmetry exist either in the scattering lengths or in the confining potentials. We suggest testing the evolution of N2-N1 by conducting echo-type experiments.

Journal Article↗