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.
The path integral is a very elegant formulation of quantum theory. It can also be an incredibly useful one, since it allows us to use methods of statistical physics, like computer simulations.
In this talk I will introduce the subject of Markov Chain Monte Carlo simulations to solve the path integral over geometries. This general introduction will use examples from Causal Dynamical Triangulations, Causal Set Theory and Non Commutative geometry to show how different issues can be explored in this manner.
The orbital angular momentum in a chiral superfluid has posed a paradox for several decades. For example, for the $p+ip$-wave superfluid of $N$ fermions, the total orbital angular momentum should be $N/2$ if all the fermions form Cooper pairs. On the other hand, it appears to be substantially suppressed from $N/2$, considering that only the fermions near the Fermi surface would be affected by the pairing interaction. To resolve the long-standing question, we studied chiral superfluids in a two-dimensional circular well, in terms of a conserved charge and spectral flows.
The primary objective of an effective field theory is modelling observables at the given scale. The subject of this talk is a notion of observable at a given scale in a context that does not rely on a metric background.
In order for quantum fluctuations during inflation to be converted to classical stochastic perturbations, they must couple to an environment which produces decoherence. Gravity introduces inevitable nonlinearities or mode couplings. We study their contribution to quantum-to-classical behavior during inflation. Working in the Schrodinger picture, we evolve the wavefunctional for scalar fluctuations, accounting for minimal gravitational nonlinearities. The reduced density matrix for a given mode is then found by integrating out shorter-scale modes.
I will present a pedagogical introduction on the application of tensor networks to the renormalization group. This program has resulted in a non-perturbative, real-space RG approach for lattice systems and the multi-scale entanglement renormalization ansatz (MERA). The MERA is currently of interest in a wide range of research areas, from statistical mechanics to condensed matter, from quantum field theory to holography in quantum gravity.