The tasks and perspectives of stringy theory of knots

The tasks and perspectives of stringy theory of knots

Alexei Morozov

ITEP Moscow

04.10.2012 Thursday/Perşembe 15:00

Place/Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
İnfo/Bilgi :  msgsufizik.net
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Acoustic superradiance from a vortex in Bose – Einstein condensates

Acoustic superradiance from a vortex in Bose – Einstein condensates

Nader Ghazanfari

Koç University, Physics Dept., İstanbul

27.09.2012 Thursday/Perşembe 15:00

Özet/Abstract : Unruh’s efforts to make a connection between propagation of sound in non-homogenous media and propagation of light in curved space time resulted in surprising systems appropriate for studying different features of the black holes such as spontaneous radiation and stimulated emissions. Acoustic superradiance is the analogue of Penrose process as a stimulated emission which is the extraction of energy from a rotating black hole. This process occurs in curved spacetime that is the geometry of rotating black holes. Event horizon in such a spacetime exists inside a region called ergoregion, and since the rotating energy of the black hole is located in between event horizon and ergosphere the extracting of energy becomes possible. In other words, in this process, the wave solution of the field equation is scattered from ergo region with an increase in its amplitude. Vortex geometry could be a nice analogue of a black hole in order to observe Penrose process since it reveals an effective ergo region which is also simple to be achieved is experiments.

Place/Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
İnfo/Bilgi :  msgsufizik.net

Perturbative construction of QED using ERG

Perturbative construction of QED using ERG

Hidenori Sonoda

Kobe University Physics Dept.

13.09-2012 Thursday / Perşembe 15:00

Özet / Abstract : I would like to explain how to use the exact renormalization group (Wilson-Polchinski differential equation) to construct QED perturbatively.  I first introduce the necessary tools using a real scalar theory as a concrete example.  I then explain how to construct QED by imposing the Ward-Takahashi identity to the solution of the ERG differential equation.  I end the talk by deriving the Khalatnikov-Landau equation for the gauge parameter dependence of the correlation functions.

Place/Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
İnfo/Bilgi :  msgsufizik.net

Cosmology in nonlinear massive gravity

Cosmology in nonlinear massive gravity

A. Emir Gümrükçüoğlu
Kavli IPMU, University of Tokyo

06-09-2012 Perşembe/Thursday 15:00

Özet/Abstract : General theory of relativity, in which the interactions have an infinite range, is in agreement with current experimental and observational data. On the other hand, from a theorist’s point of view, it is an interesting question whether the range of gravity can be consistently made to be finite, or equivalently, whether graviton can have a non-zero mass. This has been one of the most persistent challenges in classical field theory for the last 70 years. Recently, de Rham, Gabadadze and Tolley constructed a nonlinear theory of massive gravity, which successfully avoids the complications encountered before. Moreover, the theory has also phenomenological relevance, since the graviton mass may account for the accelerated expansion of the present universe, providing an alternative to dark energy. I will present self-accelerating cosmological solutions in the framework of this theory. The cosmological perturbations around these background have an interesting behaviour: instead of the 5 degrees of freedom expected from a massive spin-2 field, only the 2 gravity wave polarizations are dynamical, at linear level. However, nonlinear analysis of the extra modes reveal the existence of ghost instabilities. This implies that a consistent universe solution in this theory should be inhomogeneous and/or anisotropic.

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
Tarih : 6 Eylül 2012 Perşembe, 15:00

Mimar Sinan Güzel Sanatlar Üniversitesi Fizik Bölümü / Mimar Sinan Fine Arts University Physics Department

Mimar Sinan Güzel Sanatlar Üniversitesi Fizik Bölümü gayri resmi web sitesine hoşgeldiniz ! Resmi siteye bu linkten ulaşabilirsiniz.

Welcome to the unofficial web site of Mimar Sinan Fine Arts University Physics Department ! The official site can be found here.

msgsufizik.net