Since 2002 Perimeter Institute has been recording seminars, conference talks, public outreach events such as talks from top scientists 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 and 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.
Accessibly by anyone with internet, Perimeter aims to share the power and wonder of science with this free library.
During this talk we shall discuss the backreaction of quantum matter fields on classical backgrounds by means of the semiclassical Einstein equation.
We shall see that self consistent solutions of this coupled system exist in the case of cosmological spacetimes.
Furthermore, Einstein equations governing the backreaction will transfer quantum matter fluctuations to the metric.
In particular, we will see how the singular structure of quantum matter will affect the spectrum of metric perturbations
We construct the Haag Kaster net of von Neumann algebras for the Sine-Gordon model. This is joint work with Klaus Fredenhagen and Kasia Rejzner.
We show that a generic many-body Hamiltonian can be uniquely reconstructed from a single pair of initial-final states under the unitary time evolution. Interesting it is, this method is not practical due to its high complexity. We then propose a practical method for Hamiltonian reconstruction from multiple pairs of initial-final states. The stability of this method is mathematically proved and numerically verified.
This work is joint with Liujun Zou and Timothy Hsieh.
Recently they have been generalized to other 3d homogeneous spaces, namely 3d anti de Sitter space and half-pipe space, a 3d homogeneous space with a degenerate metric.
We show that generalized ideal tetrahedra correspond to dual tetrahedra in 3d Minkowski, de Sitter and anti de Sitter space. They are those geodesic tetrahedra whose faces are all lightlike.
I will discuss the application of Siegel paramodular forms to constructing new examples of holography. These forms are relevant to investigate the growth of coefficients in the elliptic genus of symmetric product orbifolds at large central charge. The main finding is that the landscape of symmetric product theories decomposes into two regions. In one region, the growth of the low energy states is Hagedorn, which indicates a stringy dual. In the other, the growth is much slower, and compatible with the spectrum of a supergravity theory on AdS_3.
I'll describe my recent work on black hole seeded vacuum decay, and proposals for testing seeded decay in cold atom experiments. I'll conclude with speculations on seeking insight into quantum black holes via experimentally constructing quantised analog black holes.
After a short introduction to the stochastic GW background I will highlight how one uses currently available LIGO/Virgo/Kagra data not only to learn about compact binaries and the large-scale-structure of our universe, but also to constrain particle physics models beyond the Standard Model, modified gravity proposals, and even quantum gravity theories.