Events at Physics

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Events on Friday, October 28th, 2011

Cosmology Journal Club
An Informal discussion about a broad variety of arXiv papers related to Cosmology
Time: 12:00 pm
Place: 5242 Chamberlin Hall
Abstract: Please visit the following link for more details:
Please feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Le Zhang (
Host: Peter Timbie
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Theory Seminar (High Energy/Cosmology)
Phenomenology of a pseudoscalar inflaton: naturally large non-gaussianity
Time: 2:00 pm
Place: Chamberlin 5280
Speaker: Marco Peloso, University of Minnesota
Abstract: More than 20 years ago, it has been noted that pseudoscalar axions are one of the best candidates for the inflaton field, since the flatness of their potential is protected against radiative corrections by a shift symmetry. Axions have a specific coupling to gauge fields; however, such coupling has so far received little attention in connection to inflation. We show that this coupling can actually drastically change the phenomenological predictions of the most straightforward realizations of axion inflation. The signatures in the CMB anisotropies are highly distinctive and promising: a specific and large non-gaussianity of (nearly) equilateral shape, in addition to detectably large spectral tilt and gravity waves. The same coupling can also lead to observable gravitational waves at interferometers as Advanced LIGO/VIRGO. The current bounds on non-gaussianity imply that the coupling of a pseudo-scalar inflaton to any gauge field must be smaller than about 1/10^{16} GeV; this limit is about 5 orders of magnitude stronger than the analogous limit for the coupling of the QCD axion to photons.
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Physics Department Colloquium
Nature Adorns a Vacuum: The Casimir Force
Time: 3:30 pm
Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
Speaker: Steve Lamoreaux, Yale University
Abstract: In 1948, Hendrik Casimir showed that two perfectly conducting parallel plates will be mutually attracted. This attraction is due to the modification of the the electromagnetic field mode structure between the plates, which leads to a change in the zero point energy of the field. It has only been within the last 15 years that this force has been measured to good precision, and recently the effect of finite temperature (300 K) has been measured, for the first time, in our laboratory at Yale. The notion that boundaries can affect the zero point energy of a system has broad application throughout physics, and some applications will be discussed, along with an overview of our experimental work.
Host: Heeger
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