Abstract

In the first part we will address the question of indeterminism in standard quantum theory with respect to measurement processes. A priori, it is not clear whether the outcome of a measurement is determined by the initial quantum state of the measurement device. We disprove determinism in that sense by analyzing a correlated two-particle system in an initial spin singlet state and a measurement apparatus, which measures the spin of one of the particles.

The second part will investigate decoherence in the double slit experiment for a charged particle caused by an irradiated (monochromatic) laser wave. By calculating the decoherence parameter it will be shown that the laser wave destroys the interference pattern under certain conditions, namely a high laser intensity, long interaction time and a wavelength of the laser in the order of the slit distance. Our results and further quantum features also emphasize the non absoluteness of quantum events.