Explicit wavefunction collapse and quantum measurement

In this thesis, we are concerned with models of explicit wavefunction collapse as a possible solution to the measurement problem of quantum mechanics. We examine the models where collapse is to near-position eigenstates, originally introduced by Ghirardi, Rimini and Weber in 1986, where the wavefunction is spontaneously localized at random times. Subsequent models where some of the problems of the GRW model are solved, are discussed, for both sudden localization and continuous localization processes. We comment briefly on the possible origins of collapse. The consequences of possible wavefunction collapse on the operation of quantum computers are described. Finally, we look at an attempt to describe the collapse process in a Lorentz-invariant manner.