The quantum measurement problem: nature of the apparatus

Venugopalan, A. ; Kumar, D. ; Ghosh, R. (1995) The quantum measurement problem: nature of the apparatus Current Science, 68 (1). pp. 62-67. ISSN 0011-3891

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Official URL: http://www.ias.ac.in/j_archive/currsci/68/1/62-67/...

Abstract

By considering the measurement of a quantum spin by two different models of the measuring apparatus, we try to throw some light on the nature of the apparatus that can perform quantum measurement. Our scheme is to consider a quantum spin in interaction with another quantum system playing the role of an apparatus, which in turn is dissipatively coupled to an environment. The coupling with the environment drives the density matrix of the apparatus to a diagonal form. However, measurement is performed only when the reduced density matrix of the apparatus contains correlations with the states of the spin. The two examples considered here show that this happens when the quantum apparatus has a well-defined classical limit. If the apparatus does not have a well-defined classical limit, the reduced density matrix of the apparatus is not correlated with the states of the measured system.

Item Type:Article
Source:Copyright of this article belongs to Current Science Association.
ID Code:75742
Deposited On:26 Dec 2011 12:33
Last Modified:18 May 2016 19:40

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