Ground-state energy fluctuations of a system coupled to a bath
Département de Physique Théorique, Université de Genève
CH-1211 Genève 4, Switzerland
2 Institute of Radioengineering and Electronics, Russian Academy of Sciences Mokhovaya ul. 11, 101999 Moscow, Russia
Accepted: 4 March 2002
It is often argued that a small non-degenerate quantum system coupled to a bath has a fixed energy in its ground state since a fluctuation in energy would require an energy supply from the bath. We consider a simple model of a harmonic oscillator (the system) coupled to a linear string and determine the mean-squared energy fluctuations. We also analyze the two-time correlator of the energy and discuss its behavior for a finite string.
PACS: 03.65.Yz – Decoherence; open systems; quantum statistical methods / 03.65.Ta – Foundations of quantum mechanics; measurement theory / 73.23.-b – Electronic transport in mesoscopic systems
© EDP Sciences, 2002