Parametric description of the quantum measurement process

¹ School of Mathematical Sciences, The University of Nottingham, University Park - Nottingham NG7 2RD, UK
² Dipartimento di Fisica ed Astronomia dell'Università di Firenze - Via G. Sansone 1, I-50019 Sesto F.no, Firenze, Italy
³ Istituto Nazionale di Fisica Nucleare, sezione di Firenze - Via G. Sansone 1, I-50019 Sesto F.no, Firenze, Italy
⁴ Istituto dei Sistemi Complessi ISC-CNR, UoS Dipartimento di Fisica - Via G. Sansone 1, I-50019 Sesto F.no, Firenze, Italy

Received: 14 May 2015
Accepted: 5 August 2015

Abstract

We present a description of the measurement process based on the parametric representation with environmental coherent states. This representation is specifically tailored for studying quantum systems whose environment needs being considered through the quantum-to-classical crossover. Focusing upon projective measures, and exploiting the connection between large-N quantum theories and the classical limit of related ones, we manage to push our description beyond the pre-measurement step. This allows us to show that the outcome production follows from a global-symmetry breaking, entailing the observed system's state reduction, and that the statistical nature of the process is brought about, together with the Born's rule, by the macroscopic character of the measuring apparatus.