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Why does the wave-function of a quantum system collapse during a measurement? It maybe possible to answer this question, as in the many-worlds interpretation, without modifying the theory. In this case, quantum theory is exact. On the other hand, it maybe that the theory has to be modified, as in the phenomenological model of Spontaneous Collapse. This model proposes that every quantum particle in nature undergoes spontaneous collapse, and that collapse is a fundamental property of nature, along with Schrödinger evolution. The predictions of this model differ from those of quantum theory, and we review the current experimental bounds on these models. We also review work which attempts to provide a theoretical underpinning for this phenomenological model, including the possible role of gravity, and a possible inter-connection between the measurement problem and the problem of time in quantum theory.

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T. P. Singh, Tata Institute, Mumbai
TP seminar room 0.03
Contact: Claus Kiefer