Session B02: Gravitation / Cosmology I

Fundamental Physics Tests in Astrophysics

A promising testing ground for fundamental physics is provided by the high precision measurements and observations in the solar system and beyond. Searches for hypothetical tiny deviations from perfect spacetime symmetry, which may give a glimpse of a fundamental theory of physics, have interested a growing number of researchers worldwide. This area of research is reviewed and modern tests such as lunar laser ranging, pulsar observations and gravitational wave observations are discussed. Results are reported using a systematic framework that describes generic violations of spacetime, in particular CPT and Lorentz symmetry.   

Nonlinear Kinetic Inductance Devices for Future Millimeter Wave Detection

Submillimeter and far-infrared radiation, originating from the cosmic microwave background (CMB) and warm dust in star forming galaxies, make up a significant part of the radiation in the universe. Precise studies focusing on this radiation will help answer questions about how the universe formed and provide information on cornerstone topics in physics: the big bang, the search for dark matter, and the relation between quantum mechanics and gravitational fields. Traditionally, electromagnetic radiation in this spectrum has been detected with the use of bolometers; however, bolometers have reached their limit of sensitivity. For in-depth analyses of CMB, overall sensitivity must increase. Recent developments in microwave detection technology have attempted to reduce device size to achieve greater sensitivity, one example being the kinetic inductance parametric up-converter (KPUP). KPUPs use nonlinearity in the superconductors to observe a shift in resonant frequency by a change in inductance when a DC current is applied to an inductor-capacitor circuit. Additionally, nanofabrication allows for more devices per unit area, increasing overall sensitivity. This work will focus on the design of filter components for KPUP test chips and cryogenic testing.   

Testing for Lorentz Violation with Gravitational Waves

LIGO-VIRGO GW data provides a new means of testing for Lorentz violations. We focus on the gravity sector of the SME, where a possible observable effect is birefringence: we would observe a small shift in the arrival times between the two gravitational wave polarizations from a distant source at the detectors.   

Rolling With Quantum Fields

In cosmic inflation the quantum fluctuations of the inflaton are thought to break translational symmetry. Here we study the simpler problem of a classical rolling homogeneous field bi-quadratically coupled to a quantum field. We explicitly solve the problem using the newly developed classical-quantum correspondence, in which the dynamics of a quantum variable is seen to be equivalent to that of a complexified classical variable. We find that homogeneous initial conditions evolve homogeneously such that the quantum dynamics does not break translational invariance, contrary to the common lore of cosmic inflation.