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arXiv:quant-ph/0106008

Second Quantization of Cini Model for High Order Quantum Decoherence in Quantum Measurement

Dong Zhou, Guangri Jin, C. P. Sun

Published Jun 2, 2001• 0 citations
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Abstract

By making the second quantization for the Cini Model of quantum measurement without wave function collapse [M. Cini, Nuovo Cimento, B73 27(1983)], the second order quantum decoherence (SOQD) is studied with a two mode boson system interacting with an idealized apparatus composed by two quantum oscillators. In the classical limit that the apparatus is prepared in a Fock state with a very large quantum number, or in a coherent state with average quantum numbers large enough, the SOQD phenomenon appears similar to the first order case of quantum decoherence.

DOI
10.48550/arxiv.quant-ph/0106008

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By making the second quantization for the Cini Model of quantum measurement without wave function collapse [M. Cini, Nuovo Cimento, B73 27(1983)], the second order quantum decoherence (SOQD) is studied with a two mode boson system interacting with an idealized apparatus composed by two quantum oscillators. In the classical limit that the apparatus is prepared in a Fock state with a very large quantum number, or in a coherent state with average quantum numbers large enough, the SOQD phenomenon appears similar to the first order case of quantum decoherence.
I start from the observation that the usual treatment of the object and the apparatus as independent systems in discussions of the quantum measurement process is not obviously consistent with a field theoretic picture. In such connection I consider a non relativistic second quantization model in which the role of the object is played by a particle out of the sea of the other particles in a macroscopic equilibrium state of the global system and the role of the apparatus index by the number of ions produced in certain given regions. In the framework of a formalism developed in preceding papers and in connection with the problem of decoherence, I also consider a specific, even if rather artificial, prescription to introduce a formal continuous monitoring of the particle distribution functions which would give an objective character to the macroscopic variables.
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The interaction of a quantum system with the environment leads to the so-called quantum decoherence. Beyond its fundamental significance, the understanding and the possible control of this dynamics in various scenarios is a key element for mastering quantum information processing. Here we report the quantitative probing of what can be called the quantum decoherence of detectors, a process reminiscent of the decoherence of quantum states in the presence of coupling with a reservoir. We demonstrate how the quantum features of two single-photon counters vanish under the influence of a noisy environment. We thereby experimentally witness the transition between the full-quantum operation of the measurement device to the "semi-classical regime", described by a positive Wigner function. The exact border between these two regimes is explicitely determined and measured experimentally.
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