Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 9: Transport: Quantum Coherence and Quantum Information Systems

TT 9.15: Vortrag

Montag, 25. Februar 2008, 18:00–18:15, H 2053

Preferred base for multiparticle states arising from subsequent two-particle scattering — •Ivo Knittel — Fachbereich Experimentalphysik, Campus, Geb. C6.3, 66041 Saarbrücken

For a quantum system coupled to its environment via a certain interaction operator, there exists a certain base, whose states exhibit minimal entanglement rate with environment states. For an interaction commuting with the position operator, this preferred base consists of highly localized states in position states.[1] This central result of decoherence theory is widely regarded as a solution of the 'preferred base' problem of the quantum theory of measurement [2]. However from decoherence theory it is not obvious how to construct the 'pointer states' for a given system. In this contribution, I investigate multiparticle states arising from a cascade of subsequent two-particle scattering events. This situation is met in a quasi-classical gas, or in the interaction of high-energy particles with a detector. A certain representation is constructed that is especially adapted to the multi-particle state arising from subsequent two-particle scattering events, and its time propagation.

[1] W. G Unruh, W. H. Zurek, Phys. Rev. D, 40, 1070 (1989) [2] M. Schlosshauer, Rev Mod. Phys. 76, 1267 (2004)