EPL is available also on-line on www.epljournal.org
Issue Europhys. Lett.
Volume 76, Number 4, November 2006
Page(s) 541 - 546
Section General
DOI http://dx.doi.org/10.1209/epl/i2006-10308-1
Published online 18 October 2006

Europhys. Lett., 76 (4), pp. 541-546 (2006)
DOI: 10.1209/epl/i2006-10308-1

An exactly solvable model of an avalanche-type measuring device

R. Merlin

The Harrison M. Randall Laboratory of Physics, The University of Michigan Ann Arbor, MI 48109-1040, USA


received 16 April 2006; accepted in final form 19 September 2006
published online 18 October 2006

Abstract
A quantum many-body model is presented with features similar to those of certain particle detectors. The energy spectrum contains a single, thermodynamically metastable "ready" state and macroscopically-distinct, ground "pointer" states. Transitions into classical-like states can be triggered by a single particle with the help of the thermal bath. Schrödinger cat states are associated with superpositions of inequivalent vacua, thus suggestion a relationship between wave function collapse and the dynamics of symmetry breaking in phase transformations.

PACS
03.65.Ta - Foundations of quantum mechanics; measurement theory.
03.70.+k - Theory of quantized fields.

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