## Upcoming Seminars

Date/Place | Nov. 21th (Tues.) 15:30-16:30 / H711 |
---|---|

Name | Nilay Kundu (YITP, Kyoto Univ.) |

Title | Second law of black-hole thermodynamics in Lovelock theories of gravity |

Abstract | In this talk we will discuss the construction of an entropy function for dynamical black holes in a specific higher derivative theory of gravity, namely Lovelock theories. As is known, in classical general relativity described by Einstein-Hilbert gravity, black holes behave as thermodynamic objects. The first law of black hole mechanics extends to higher derivative theories via the Noether charge construction of Wald. In order to extend the second law (which in Einstein-Hilbert theory owes to Hawking's area theorem) to higher derivative theories one needs a notion of entropy for dynamical black holes beyond the Noether charge construction. We will discuss one such possible extension for the Lovelock theories of gravity, treating the higher derivative terms as perturbations to Einstein's gravity. |

Date/Place | Nov. 28th (Tues.) 15:30-16:30 / H711 |
---|---|

Name | Jnanadeva Maharana (Bhubaneswar, India) |

Title | T-duality and Scattering of String States |

Abstract | I shall briefly recall the salient features of T-duality for a closed bosonic string compactified on a d-dimensional torus. The vertex operators associated with the closed compactified bosonic string in the massless sector will be introduced. They are defined in the weak field approximation. The symmetry properties of the S-matrix elements under T-duality for the moduli will be discussed. The Kawai-Lewellyn-Tye approach will be utilzed to show transformations of S-matrix elements under T-duality. |