Astronomy and Astrophysics Seminars
Fluctuating gravitational field as an explanation for quantum decoherence: its implication and detection
by Ms. Sayantani Bera, (Dept. of Astronomy & Astrophysics, Tata Institute of Fundamental Resear)
Tuesday, March 21, 2017 from to (Asia/Kolkata)
at DAA ( A269 )
at DAA ( A269 )
The theory of quantum mechanics, despite being highly successful, is plagued with foundational issues such as the “measurement problem”. Understanding the process of “measurement” and the random collapse of the wavefunctions from a more profound perspective than the standard Copenhagen picture have been one of the major aims in foundational quantum mechanics. Possibilities that the wavefunction collapse is a manifestation of the non-standard coupling of the quantum particles with the background gravitational field have also been explored in this context. In this talk, I will focus on one such proposal called the “Schrodinger-Newton scheme” in the semi-classical theory of gravity. This theory deals with the effect of self-gravity of a quantum particle on its wavefunction evolution leading to a spontaneous collapse. However, this is a deterministic theory and in order to account for the random outcomes one has to introduce stochasticity in the evolution equation. I will discuss possible ways to introduce stochasticity in the dynamics by considering separately an external stochastic gravity background and by taking into account the higher order fluctuation terms to the Schrodinger-Newton equation itself. I will derive the “decoherence time” in these two cases and show that they match with the previously known “Diosi-Penrose” criterion, which might be an indication of a universal scale at which the interplay of gravity and quantum mechanics becomes important. Lastly, I will briefly talk about scenarios where such effects can be experimentally detected.