Search Talks

Anthropic arguments based on selection effects for observers have been claimed to succesfully explain the measured value of the cosmological constant.In this talk I review the fundations of such claims in the context of probability theory and show that different (and equally legitimate) ways of assigning probabilities to candidate universes lead to totally different anthropic predictions. As an explicit example, I discuss a weighting scheme based on the total number of possible observations that observers can carry out over the entire lifetime of the Universe. I show that this leads to an extremely small probability for observing a value of the cosmological constant equal to or greater than what we now measure, in marked contrast with the usual result. I also discuss principles of consistent probabilistic reasoning, showing that the anthropic principle as applied in most of the literature is logically inconsistent. I conclude that current implementations of the anthropic principle display a worrysome lack of predictivity, and cannot be used to explain the value of the cosmological constant, nor, likely, any other physical parameters.

Abstract: This group of astronomical order is slowly yielding its secrets.It is the symmetry group of a rational conformal field theory. In thisintroductory talk, I will discuss the functions that constitute monstrousmoonshine and explain the importance of the monster group and itsconnections with better established parts of mathematics

The possibility that rotational invariance ins broken during the inflationary era is discussed. The implications of this for the microwave background asymmetry are derived using a model independent approach. A particular inflationary model that realizes these ideas is studied.

Hollywood movies about aliens abound, but do they really exist? The real scientific search for evidence of life, and particularly intelligent life, elsewhere in the cosmos is just as exciting as the “reel” version, and a lot more logical. So far, there is ‘life-as-we-know-it’ to guide our speculations and observations. But a new appreciation for the tenacity of life, a growing respect for the world of microbes, and new search technologies involving observatories and spacecraft are rapidly expanding our viewpoint. Many expect surprises. SETI is at the forefront of this research and has plans to extend its range out even further into the galaxy, looking for evidence of someone else’s technology. In the next few decades, scientists will take a much closer look at places within our solar system where liquid water (even vast oceans) may exist and harbor life. They will also probe the closest stars to see if other ‘Earths’ and biospheres exist. Dr. Jill Tarter will describe research in a discipline some call “the archaeology of the future”. Jill Tarter, extraterrestrial intelligence, SETI, \'archaeology of the future\', stardust, microbes, extreme life conditions, astrobiology, Kepler probe, Corot probe

We show that singlets composed of multiple multi-level quantum systems can naturally arise as the ground state of a physically-motivated Hamiltonian. The Hamiltonian needs to be one which simply exchanges the states of nearest neighbours in any graph of interacting d-level quantum systems (qudits) as long as the graph also has d sites. We point out that local measurements on some of these qudits, with the freedom of choosing a distinct measurement basis at each qudit randomly from an infinite set of bases, project the remainder onto a singlet state. One implication of this is that the entanglement in these states is very robust (persistent), while an application is in establishing an arbitrary amount of entanglement between well-separated parties (for subsequent use as a communication resource) by local measurements on an appropriate graph. Based on quant-ph/0602139.