Where is everybody? : Starts With A Bang
Greetings from Avignon , where I’m attending a conference on “Progress on Old and New Themes” in cosmology. (Name chosen to create a clever acronym .) Avignon Day 1: Calculating Non-Gaussianities | Cosmic Variance
Yesterday’s talks were devoted to the idea of dark matter, which as you know is the hottest topic in cosmology these days, both theoretically and experimentally. Eric Armengaud and Lars Bergstrom gave updates on the state of direct searches and indirect searches for dark matter, respectively. John March-Russell gave a theory talk about possible connections between dark matter and the baryon asymmetry. The density of dark matter and ordinary matter in the universe is the same, to within an order of magnitude, even though we usually think of them as arising from completely different mechanisms. That’s a coincidence that bugs some people, and the last couple of years have seen a boomlet of papers proposing models in which the two phenomena are actually connected. Tracy Slatyer gave an update on proposals for a new dark force coupled to dark matter, which could give rise to interesting signatures in both direct and indirect detection experiments. Avignon Day 4: Dark Matter | Cosmic Variance
Is space like a chessboard? Mar. 20, 2011 — Physicists at UCLA set out to design a better transistor and ended up discovering a new way to think about the structure of space. Space is usually considered infinitely divisible -- given any two positions, there is always a position halfway between. But in a recent study aimed at developing ultra-fast transistors using graphene, researchers from the UCLA Department of Physics and Astronomy and the California NanoSystems Institute show that dividing space into discrete locations, like a chessboard, may explain how point-like electrons, which have no finite radius, manage to carry their intrinsic angular momentum, or "spin." While studying graphene's electronic properties, professor Chris Regan and graduate student Matthew Mecklenburg found that a particle can acquire spin by living in a space with two types of positions -- dark tiles and light tiles. The particle seems to spin if the tiles are so close together that their separation cannot be detected.
Progress on Old and New Themes in cosmology (PONT) 2011 (18-22 April 2011) In conjunction with a having a key associated with your account, to have the possibility of exporting private event information necessitates the creation of a persistent key. This new key is also associated with your account and whilst it is active the data which can be obtained through using this key can be obtained by anyone in possession of the link provided. Due to this reason, it is extremely important that you keep links generated with this key private and for your use only. If you think someone else may have acquired access to a link using this key in the future, you must immediately remove it from 'My Profile' under the 'HTTP API' tab and generate a new key before regenerating iCalendar links. I have read and understood the above.
"Non-Gaussianities in the temperature fluctuations of the Cosmic Microwave Background" sounds like a perfect conversation topic to put your date to sleep, but if you have an interest in Cosmology or Quantum Gravity, it's definitely something you should have heard about. The Cosmic Microwave Background (CMB) is radiation we receive today from a time when the universe was about 300,000 years young. At that time, radiation decoupled from matter and since then, photons could travel almost undisturbed. Non-Gaussianities in the CMB
Chiral perturbation theory Chiral perturbation theory (ChPT) is an effective field theory constructed with a Lagrangian consistent with the (approximate) chiral symmetry of quantum chromodynamics (QCD), as well as the other symmetries of parity and charge conjugation. ChPT is a theory which allows one to study the low-energy dynamics of QCD. As QCD becomes non-perturbative at low energy, it is impossible to use perturbative methods to extract information from the partition function of QCD. Lattice QCD is one alternative method that has proved successful in extracting non-perturbative information. In the low-energy regime of QCD, the degrees of freedom are no longer quarks and gluons , but rather hadrons .