Talks

Long before the emergence of planets, stars, or galaxies, the universe consisted of an exploding quantum soup of “elementary” particles. Encoded in this formless, shapeless soup were seeds of cosmic structure, which over billions of years grew into the beautiful and complex universe we observe today. The lecture will explore the connection between the “inner space” of the quantum and the “outer space” of the cosmos. The inner space/outer space connection may hold the key to the nature of the dark matter holding together our galaxy and the mysterious dark energy pulling apart our universe. Edward W. Kolb (known to most as Rocky) is a founding head of the NASA/Fermilab Astrophysics Group at Fermi National Accelerator Laboratory and a Professor of Astronomy and Astrophysics at The University of Chicago. Presently he is the Director of the Particle Astrophysics Center at Fermilab. A native of New Orleans, he received his Ph.D. in physics from the University of Texas. Postdoctoral research was performed at the California Institute of Technology and Los Alamos National Laboratory where he was the J. Robert Oppenheimer Research Fellow. He has served on editorial boards of several international scientific journals as well as Astronomy magazine. In addition to over 200 scientific papers, he is a co-author of The Early Universe, the standard textbook on particle physics and cosmology. His book for the general event, Blind Watchers of the Sky, received the 1996 Emme Award of the American Aeronautical Society. Rocky teaches cosmology to non-science majors at the University of Chicago and is involved with pre-college education enrichment programs. He has traveled the world, if not yet the Universe, giving scientific and event lectures. He has appeared in several television productions, and can also be seen in the OMNIMAX/IMAX film The Cosmic Voyage. His distinctions include: Fellow of the American Academy of Arts and Sciences, Fellow of the American Physical Society, recipient of the 2003 Oersted Medal of the American Association of Physics Teachers, winner of the 1993 Quantrell Prize for teaching excellence at the University of Chicago, Harlow Shapley Visiting Lecturer and Centennial Lecturer with the American Astronomical Society. He has also presented event lectures at the Royal Society of London, and in Rio de Janeiro, Valencia, and Barcelona. cosmos, quantum, cosmology, universe, galaxies collide, Barnes, Hibbard, Newton, Einstein, relativity, space, time, origin of the universe, dark energy, expansion history, vacuum quantum, Vera Rubin, invisible universe, dark matter, quantum universe, Higgs potential, Big Bang Theory, Hubble, WIMPS, cosmic background radiation

Adiabatic Quantum Computation is not only a possibly more robust alternative to standard quantum computation. Since it considers a continuous-time evolution of the system, it also provides a natural bridge towards studying the dynamics of interacting many-particle quantum systems, quantum phase transitions and other issues in fundamental physics. After a brief review of adiabatic quantum computation, I will show our recent results on the dynamics of entanglement and fidelity for the search and Deutsch algorithms including several variations and optimization. I will show how these studies led to suggesting an alternative definition of entanglement and compare the results, and discuss possible implications for considering entanglement a resource. I will conclude with an outlook on further applications and extensions of adiabatic quantum computation.

Einstein\'s famous equation E=mc2 asserts that energy and mass are different aspects of the same reality. It is usually associated with the idea that small amounts of mass can be converted into large amounts of energy. For fundamental physics, however, the more important idea is just the opposite. Researchers want to explain how mass itself arises, by explaining it in terms of more basic concepts. In this lecture targeted for a general audience, Prof. Wilczek will explain how this goal can, to a remarkable extent, be achieved. He will also discuss some of the consequences - an explanation of why gravity is so feeble - and suggestions for new physical phenomena at the Large Hadron Collider (LHC) in Geneva. Prof. Wilczek is a distinguished scientist and lecturer. He is the author of Fantastic Realities: 49 Mind Journeys and a trip to Stockholm and co-author of Longing for the Harmonies. In addition to many distinguished memberships and affiliations, he is a member of Perimeter Institute’s Scientific Advisory Committee.

Category theory is a general language for describing things and processes - called "objects" and "morphisms". In this language, many counterintuitive features of quantum theory turn out to be properties shared by the category of Hilbert spaces and the category of cobordisms, in which objects are choices of "space" and emorphisms are choices of "spacetime". This striking fact suggests that "n-categories with duals" are a promising language for a quantum theory of spacetime. We sketch the historical development of these ideas from Feynman diagrams to string theory, topological quantum field theory, spin networks and spin foams, and especially recent work on open-closed string theory, 3d quantum gravity coupled to point particles, and 4d BF theory coupled to strings.

It has recently been proposed by Nayeri, Brandenberger and Vafa, that the thermodynamics of strings in the early universe can provide us with a causal mechanism to generate a scale invariant spectrum of primordial density fluctuations, without requiring an intervening epoch of inflation. We will review this mechanism, and report on more recent work which has uncovered several observational consequences of the NBV mechanism, some of which in principle, will be distinguishable from the generic predictions of inflation.

We propose a new brane world scenario. In our model, the Universe starts as a small bulk filled with a dense gas of branes. The bulk is bounded by two orbifold fixed planes. An initial stage of isotropic expansion ends once a weak potential between the orbifold fixed planes begins to dominate, leading to contraction of the extra spatial dimensions. Depending on the form of the potential, one may obtain either a non-inflationary scenario which solves the entropy and horizon problem, or an improved brane-antibrane inflation model.

Clifton, Bub, and Halvorson claim to be able to derive quantum mechanics from information-theoretic axioms. However, their derivation relies on the auxiliary assumption that the relevant probabilities for measurement outcomes can be represented by the observables (self-adjoint operators) and states of a C*-algebra. There are legitimate probability theories that are not so representable --- in particular, the nonlocal boxes of Popescu and Rohrlich. We explain the impact of nonlocal boxes on the interpretation of the CBH derivation, and we discuss possible generalizations of the CBH derivation in the framework of these more general probability theories.

Radiation Delivery, cancer, radiation therapy, electron, isocentre, planned target volume, adaptive radiotherapy, multi-leaf collimator, energy deposition, multi-beam delivery, intensity modulation, optimal radiation treatment, matrix inversion, inverse planning optimization, symmetries, fast inverse dose optimization