Talk detail

Participant	Singh, Dinesh
Institution	University of Regina - 3737 Wascana Parkway - Regina - Saskatchewan - Canada

Session	QG2	Accepted		Order	Time
Talk	Oral abstract	Title	A New Perspective on Path Integral Quantum Mechanics in Curved Space-Time
Co-authors
Abstract	A fundamentally different approach to path integral quantum mechanics in curved space-time is presented, as compared to the standard approaches currently available in the literature. Within the context of scalar particle propagation in a locally curved background, such as described by Fermi or Riemann normal co-ordinates, this approach requires use of a constructed unitary projection operator to rotate the initial, intermediate, and final position ket vectors onto their respective local tangent spaces, defined at each proper time step along some arbitrary classical reference worldline. Proper time translation is described using a quantum mechanical representation of Lie transport, that while strictly non-unitary in operator form, nevertheless correctly describes free-particle propagation in the absence of space-time curvature. This propagator yields the prediction that all probability violating terms due to curvature contribute to a quantum violation of the weak equivalence principle, while the remaining terms that conserve probability also correspondingly satisfy the weak equivalence principle, at least to leading order in the particle's Compton wavelength. Furthermore, this propagator possesses an overall curvature-dependent and gauge-invariant phase factor that identically vanishes for zero net spatial separation between the initial and final position.

Session	AT3	Accepted		Order	Time
Talk	Oral abstract	Title	Bounded Orbits of Classical Spinning Particles in Black Hole Space-Time Backgrounds
Co-authors
Abstract	The Mathisson-Papapetrou-Dixon (MPD) equations describe the dynamics of a spinning test particle due to direct spin-curvature coupling, while propagating in a general gravitational background. As such, it is theoretically possible to use the MPD equations as a diagnostic tool to probe the structure of curved space-time in suitable astrophysical contexts. An illustration of this is given by comparing the numerical simulation of a spinning test particle in quasi-elliptical motion around a Kerr black hole with that of a non-rotating dynamical black hole in its late-time ringdown state following a merger with another black hole. The latter is described in terms of the Vaidya metric for several cases of an oscillating mass function with predetermined surface profiles and amplitude strengths, to serve as a calibration tool for understanding their correspondence with the spinning particle’s orbital response. As a proof-of-principle concept, leading-order gravitational waveforms generated by the spinning particle are compared for both space-time backgrounds, assuming that the spinning particle is a solar mass millisecond pulsar orbiting a thousand solar mass black hole. In so doing, the MPD equations provide another means to search for signatures of black hole mergers and observationally probe the verification of the black hole no-hair theorem.