Cosmology & Gravitation

This series consists of talks in the areas of Cosmology, Gravitation and Particle Physics.

Seminar Series Events/Videos

Currently there are no upcoming talks in this series.

 

Tuesday Apr 13, 2010
Speaker(s): 

We discuss a candidate mechanism through which one might address the various cosmological constant problems. We observe that the renormalization of gravitational couplings manifests non-local modifications to Einstein's equations as quantum corrected equations of motion, and in doing so offers a complimentary realization of the degravitation paradigm-- a realization through which its non-linear completion and the corresponding modified Bianchi identities are readily understood.

Collection/Series: 
Scientific Areas: 

 

Tuesday Apr 06, 2010
Speaker(s): 

After prodigious work over several decades, binary black hole mergers can now be simulated in fully nonlinear numerical relativity. However, these simulations are still restricted to mass ratios q = m2/m1 > 1/10, initial spins a/M < 0.9, and initial separations r/M < 10. Fortunately, analytical techniques like black-hole perturbation theory and the post-Newtonian approximation allow us to study much of this region in parameter space that remains inaccessible to numerical relativity.

Collection/Series: 
Scientific Areas: 

 

Tuesday Mar 23, 2010
Speaker(s): 

Stellar evolution from a protostar to neutron star is of one of the best
studied subjects in modern astrophysics. Yet, it appears that there is still
a lot to learn about the extreme conditions where the fundamental particle physics meets strong gravity regime. After all of the thermonuclear fuel is spent, and
after the supernova explosion, but before the remaining mass crosses its own
Schwarzschild radius, the temperature of the central core of the star might
become higher than the electroweak symmetry restoration temperature. The

Collection/Series: 
Scientific Areas: 

 

Tuesday Mar 09, 2010
Speaker(s): 

We report on a new class of fast-roll inflationary models. In a part of its parameter space, inflationary perturbations exhibit quite unusual phenomena such as scalar and tensor modes freezing out at widely different times, as well as scalar modes reentering the horizon during inflation. One specific point in parameter space is characterized by extraordinary behavior of the scalar perturbations. Freeze-out of

Collection/Series: 
Scientific Areas: 

 

Tuesday Mar 02, 2010
Speaker(s): 

Primordial non-Gaussianity has been traditionaly constrained using three-point function of the cosmic microwave background. Two years ago, however, Dalal et al have shown that non-Gaussianity of the local type induces a scale dependent bias for biased tracers of the underlying dark matter structure. This allows constraining of the primordial non-Gaussianity from measurements of large-scale structure provided by redshift surveys. I will discuss the technique, its theoretical aspects,

Collection/Series: 
Scientific Areas: 

 

Tuesday Feb 02, 2010
Speaker(s): 

The quest to understand the nature of dark matter is entering a remarkable data-rich era. Hypothetical stable, electrically neutral particles with TeV-scale mass and weak-strength couplings are a simple, theoretically appealing, but untested candidate for the dark matter. I will summarize recent results in both direct and indirect searches for dark matter, and highlight what upcoming data may teach us. I will also discuss the key role of accelerator-based experiments and novel astrophysical measurements in understanding dark matter and its connection to Standard Model physics.

Collection/Series: 
Scientific Areas: 

 

Monday Feb 01, 2010
Speaker(s): 

The LHC will explore fundamental physics at a new energy frontier. A spectrum of new particles at the TeV scale is expected on two theoretical grounds: explaining dark matter and generating the electroweak scale. Understanding the properties of such particles can clarify the nature of dark matter, the origin of the weak scale, symmetries of nature, and the multiverse. These particles can be discovered by identifying collision events characteristic of new physics in LHC data.

Collection/Series: 
Scientific Areas: 

 

Thursday Jan 21, 2010
Speaker(s): 

While the properties of gravity, and its consistency with General Relativity (GR), are well tested on solar system scales, within our system and the decay of binary pulsar orbits, they are, by comparison, poorly tested on cosmic scales. This is of particular interest as we try to understand the origins of cosmic acceleration, and whether they are a signature of deviations from GR.

Collection/Series: 
Scientific Areas: 

Pages