In the post-Higgs era, the theoretical challenge in flavor symmetry is to show how it should also predict a scalar boson very much like the observed 126 GeV particle at the LHC. I will discuss such a model of quark and lepton flavor symmetry based on $S_3$ proposed originally in 2004. I will show that this model has the unique prediction of a measurable branching fraction of up to $10^{-7}$ for $B_s \to \tau^+ \mu^-$, but that for $B_s \to \tau^- \mu^+$ is suppressed by an additional factor of $(m_\mu/m_\tau)^2$.

We discuss thermodynamics of N M2- and M5-branes by using the method proposed by Smilga and Wiseman, which explains the black Dp-brane thermodynamics from the maximally supersymmetric U(N) Yang-Mills theories. As result we obtain the consistent results with the predictions from the eleven-dimensional supergravity by very simple calculations: The free energy of M2-branes is evaluated by using ABJM theory as F ~ N^{3/2}k^{1/2}T^3, and that of M5-branes is estimated by assuming some natural properties of 6d conformal field theory as F ~ N^3T^6.

１９世紀末から２０世紀初頭にウィーンで生まれもしくはウィーンで活躍した物理学者は例えば　 L. Boltzmann, V. Hess, E. Schrodinger, W. Pauli. L. Meitner など有名な例が多いです。 その物理学者の記念と なるところおよび町の雰囲気をこのセミナールで紹介したいと思います。 特に Boltzmann と Schrodinger の生涯を取り上げ、模範的な考え方 と生き方などについて皆さんと一緒に考えて見たいと思います。

ここ四半世紀、アハロノフの弱値 weak value という妖怪が、量子論界隈を徘徊してやむ事がなかった。「弱い測定 weak measurement」による実験的実現も得る一方、 数多くの論文の中で時に神秘的な装いで現れるこの弱値概念であるが、しかしこれを通常の量子力学の形式の中でどう理解すればいいのか、多くの研究家が頭を悩ませてきたのも事実である。今回の話では、この量子的弱値を、ヒルベルト空間の直交系を用いたごく普通の量子論の定式化の枠組みに、どう位置づけるかを考えてみたい。ここで鍵となるのが「量子演算子を完全に記述する弱値の一式」という考え方である。 さらにそのような一式を持ち出す利点を、「射影測定を行う時どのような場合に歴史を消せるか」という応用問題を取り上げて説明してみたい。

The inflaton must convert its energy into radiation after inflation, which, in a conventional scenario, is caused by the perturbative decay of inflaton.

However, the process of reheating would be much more complicated in some cases, since the decay products obtain masses from an oscillating inflaton and thermal environment. Hence, the conventional reheating scenario where the reheating takes place via the perturbative decay of inflaton can be modified. We study in detail processes of reheating: non-perturbative particle production from the inflaton and the subsequent evolution of inflaton/plasma system by taking account for the thermal dissipation of inflaton in a hot plasma.

In this talk, at first, I would like to explain general aspects of dynamics of oscillating scalar field in the early universe, and then, move on to its application to the reheating after inflation. In particular, I will show that the reheating temperature is significantly affected by the thermal dissipation; especially the deviation from the conventional reheating scenario becomes prominent for smaller inflaton mass.

n-DBI gravity is a gravitational theory motivated by Dirac-Born-Infeld type conformal scalar theory and designed to yield non-eternal inflation spontaneously without introducing any scalar field. It contains the space-time foliation provided by an everywhere time-like vector field n, which couples to the gravitational sector of the theory, but decouples in the small curvature limit. In my talk, I will explain some theoretical aspects of the model in detail by showing its interesting black hole solutions.

In the first talk, we will give an overview of string phenomenology.
In the second talk, we will argue cosmology in 4 dimensional N=1 supergravity which can be derived from type IIB supergravity in flux vacua. We will show that dark radiation, which is a reletivistic dark matter, is naturally generated from the decay of the overall volume modulus in the LARGE volume scenario. Then, the axionic superpartner of the modulus accounts for the dark radiation, which is constrained by the observation of CMB by the Planck satellite, while the modulus decay into Higgses through the Giudice-Masiero term gives the contribution to a reheating temperature of our sector. To obtain a viable reheating, we need, say, 9 Higgs doublet pairs; otherwise too much dark radiation is obtained. Hence, this illustrates a new type of moduli problem: Moduli-induced axion problem. Then, if viable, we can find also the candidates of cold (non-relativistic) dark matter, which are Wino and/or QCD axion.