Measurement Quantum Mechanics and Experiments on Quantum Zeno Effect

Abstract

Measurement quantum mechanics, the theory of a quantum system which undergoes a measurement process, is introduced by a loop of mathematical equivalencies connecting previously proposed approaches. The unique phenomenological parameter of the theory is linked to the physical properties of an informational environment acting as a measurement apparatus which allows for an objective role of the observer. Comparison with a recently reported experiment suggests how to investigate novel interesting regimes for the quantum Zeno effect.03.65.Bz, 42.50.Wm

Dynamics of decoherence in continuous atom-optical quantum nondemolition measurements

“…the beam variance. This qualitatively agrees with the result established in [11], concerning the direct proportionality between the measurement coupling constant and the temperature of the bath in which the meter is embedded [11]. Unlike the parameter γ, it is not possible to infer a simple relationship relating κ to the various parameters of the realistic configuration.…”

“…In this article, we analyze a model for QND measurements based on Lindblad formalism, specializing it to measurement strategies aimed at describing continuous quantum nondemolition counting of photons confined in a cavity or atoms interrogated to be in a certain internal state. The system is described by a density matrix with an evolution equation introduced for generic open quantum systems [10] and already applied to other, demolitive measurement schemes such as the ones involving the quantum Zeno effect in hyperfine atomic spectroscopy [11], optogravitational cavities [12], superconducting circuits [13], and trapped ions [14]. In both cases the evolution of the coherence of the monitored system is studied, providing a simple picture of its decay during continuous QND measurements.…”

Statistics of measurement of noncommuting quantum variables: Monitoring and purification of a qubit

“…͑17͒ for multidetector setup, complies with a Lindblad scheme. 33,34 We will show this explicitly in Appendix B. This guarantees the positivity of the "big" density matrix…”

Test of some fundamental principles in physics via quantum interference with neutrons and photons

“…Though there are several attempts to solve this old conundrum (some of them are equivalent [129]), here we will explain the restricted path integral formalism (RPIF) [130]. This particular choice has behind it a sound reason.…”