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.
Suppose we are given two probability distributions on some N-element set. How many samples do we need to test whether the two distributions are close or far from each other in the L_1 norm? This problem known as Statistical Difference has been extensively studied during the last years in the field of property testing. I will describe quantum algorithms for Statistical Difference problem that provide a polynomial speed up in terms of the query complexity compared to the known classical lower bounds.
Astronomers have discovered many candidate black holes in the universe and have studied their properties in ever-increasing detail. Over the last decade, a few groups have developed observational tests for the presence of event horizons in candidate black holes. The talk will discuss one of these tests, which indicates that the supermassive black hole at the center of our Galaxy must have a horizon.
I will discuss the possibility that a 'Wilson line' degree of freedom can play the role of an inflaton in a warped flux compactification, in the context of the DBI inflationary scenario. I will show how warped DBI Wilson line inflation offers an attractive alternative to ordinary (position field) DBI inflation, inasmuch as observational and theoretical constraints get considerably relaxed. Thus, besides the large non-Gaussianities produced in DBI scenarios, Wilson lines allow for an observable amount of gravitational waves, within consistent approximations.
Over the last two years, the Compact Muon Solenoid (CMS) detector has been installed in the tunnel of the Large Hadron Collider (LHC) at CERN and commissioned to its full functionality. The CMS detector successfully collected beam halo and beam dump data, while the beams were circulating in the LHC in September 2008. After the LHC incident, the commissioning of CMS continued with a one month campaign of continuous cosmic rays data taking at nominal magnetic field. This allowed further tuning of the detector, consolidation of its operation and characterization of its performances.
Our universe is unquestionably quantum in nature. What does this mean? Why does it matter? What’s in it for me? Join us for a fun and fascinating session on “what you need to know about the quantum.” Find out why we can’t live without it. Discover what’s so unbelievably quirky about it. And learn how it empowers amazing technologies, from present day (e.g. every electronic device on the planet) to future possibilities including quantum computing and global quantum communication.
This course provides a thorough introduction to the bosonic string based on the Polyakov path integral and conformal field theory. We introduce central ideas of string theory, the tools of conformal field theory, the Polyakov path integral, and the covariant quantization of the string. We discuss string interactions and cover the tree-level and one loop amplitudes. More advanced topics such as T-duality and D-branes will be taught as part of the course. The course is geared for M.Sc. and Ph.D. students enrolled in Collaborative Ph.D. Program in Theoretical Physics.
This course provides a thorough introduction to the bosonic string based on the Polyakov path integral and conformal field theory. We introduce central ideas of string theory, the tools of conformal field theory, the Polyakov path integral, and the covariant quantization of the string. We discuss string interactions and cover the tree-level and one loop amplitudes. More advanced topics such as T-duality and D-branes will be taught as part of the course. The course is geared for M.Sc. and Ph.D. students enrolled in Collaborative Ph.D. Program in Theoretical Physics.
We derive geometric correlation functions in the new spinfoam model with coherent states techniques, making connection with quantum Regge calculus and perturbative quantum gravity. In particular we recover the expected scaling with distance for all components of the propagator. We expect the same technique to be well-suited for other spinfoam models.
To interface photons with solid-state devices, we investigated the coupling of optically active quantum dots with optical micro- and nano-cavities. Initial experimental progress have led to the unexpected observation of ultra low threshold lasing of a photonic crystal defect mode cavity embedded with only 1 to 3 InAs self-assembled quantum dots as gain medium. Photon correlation measurements confirmed the transition from a thermal light source to a coherent light source.
We have only scratched the surface of the potential for using large-scale structure (LSS) as a probe of fundamental physics/cosmology, i.e., quantitatively, we have only measured a small fraction of a percent of the accessible LSS information. Future measurements will probe dark energy, inflation, dark matter properties, neutrino masses, modifications of gravity, etc. with unprecedented precision.