Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
In this talk I will discuss an alternative to infation models, namely non singular bouncing models.Their advantage is to supress both the transplanckian problem and the big bang singularity. It also gives a scale invariant power spectrum in the case of amatter bounce.First we will study a toy model, the non singular matter bounce. Then we will try to see what is the effect when we add upradiation through a gauge fields. To do that we add up a coupling term between the scalar fields and the gauge fields to see if it destroys the bounce or not.
(n+1)-dimensional Lifshitz spacetime is deformed by logarithmic expansions in the way to admit a marginally relevant mode in which z is restricted by n=z+1. According to the holographic principle, the deformed spacetime is assumed to be dual for quantum critical theories, and then thermodynamics of generic black holes in the bulk describe the field theory with a dynamically generated momentum scale $Lambda$. This is a basically UV-expanded theory considered in higher dimensions of the Lifshitz holography from the previous works.
TBA
A recent analysis of gamma rays from the centre of our galaxy has provided possible evidence for a dark matter annihilation signal, with the dark matter taking the form of low-mass WIMPs annihilating predominantly to taus. We study an extended Higgs model proposed to yield such a dark matter candidate. Scanning over parameter space in this model, we find suitable areas that feature fairly little fine-tuning. In favoured areas, the cross-sections for invisible decays of neutral Higgses are predicted to be too low for detection atcolliders.
This is a very informal talk about some of the issues associated with the notion of "macroscopic realism" (MR) and its relation to quantum mechanics (QM).
Magnetic fields of stars can provide insight on their structure and evolution. These magnetic fields can be detected by exploiting the Zeeman effect. The theory behind detection and the method of Lease Squares Deconvolution will be described and preliminary results will be presented.
Neutron stars are the collapsed cores of massive stars that went under supernova explosions. They are found with high surface magnetic fields, rapid but steady rotation and high density comparable to that inside an atomic nucleus. In the past 20 years, many different classes of neutron stars have been discovered. One of the most enigmatic classes of neutron stars is the compact central objects (CCOs). Only seven of them have been discovered and their emission process are still not well understood.
The large number of high-energy rotational lines of C18O, available via the Herschel Space Observatory, provides an unprecedented ability to model the total C18O column density in hot cores. Using the emission from all the observed lines (up to J=16-15) we use an automated algorithm to model all transitions simultaneously.
Neutron stars are collapsed remnants of massive stars. One form of neutron star, pulsars, produce clock-like radio pulses, a result of their rotation combined with a misalignment of their rotation and magnetic axes. These pulses can be used in a variety of experiments in fundamental physics, including tests of gravity theories, constraining the properties of supranuclear density matter, and gravitational wave detection. In this talk, I will describe pulsar properties and explain how the above experiments are carried out, as well as show interesting recent results.