Upcoming Seminars

Date/Place Oct. 16th (Tue.) 15:30-16:30 / H711
Name Yu Hamada (Kyoto University)
Title Axial U(1) current in Grabowska and Kaplan’s formulation
Abstract Recently, Grabowska and Kaplan suggested a non-perturbative formulation of a chiral gauge theory (arXiv: 1511.03649). This formulation consists of the conventional domain-wall fermion and a gauge field that evolves by the gradient flow from one domain wall to the other. In this talk, I will briefly review their formulation and some related works. I will also discuss the QCD axial U(1) current in the formulation. It is found that the naive definition of the current does not reproduce the axial anomaly because the current includes a contribution from the bulk. I will suggest the correct definition of the current. This talk is based on the collaboration with Hikaru Kawai (arXiv: 1705.01317).

 

Date/Place Oct. 23th (Tue.) 15:30-16:30 / H711
Name Hiroyuki Tashiro (Nagoya University)
Title Cosmology with the measurements of redshifted 21 cm signals
Abstract Observations of cosmological 21 cm signals are expected to provide a new window to the universe. The observed signals are sensitive to the structure formation, the thermal evolution and the expansion history of the universe. Recently the first detection of the cosmological 21 cm signal around the redshift 20 was claimed by the EDGES collaboration. In this talk, I will give the theoretical introduction of cosmological 21 cm observations. Reviewing the EDGES result, I will also discuss its application to cosmological problems including the dark matter modelling.

 

Date/Place Nov. 13th (Tue.) 15:30-16:30 / H711
Name Goro Ishiki (University of Tsukuba)
Title Spherical transverse M5-branes from the plane wave matrix model
Abstract We consider the matrix theoretical description of transverse M5-branes in M-theory on the 11-dimensional maximally supersymmetric pp-wave background. We apply the localization to the plane wave matrix model (PWMM) and show that the transverse spherical fivebranes with zero light cone energy in M-theory are realized as the distribution of low energy moduli of the SO(6) scalar fields in PWMM.

 

Date/Place Nov. 20th (Tue.) 15:30-16:30 / H711
Name Tomonori Ugajin (OIST)
Title Modular Hamiltonians of excited states, OPE blocks and emergent bulk fields
Abstract We study the entanglement entropy and the modular Hamiltonian of slightly excited states reduced to a ball shaped region in generic conformal field theories. We set up a formal expansion in the one point functions of the state in which all orders are explicitly given in terms of integrals of multi-point functions along the vacuum modular flow, without a need for replica index analytic continuation. We show that the quadratic order contributions in this expansion can be calculated in a way expected from holography, namely via the bulk canonical energy for the entanglement entropy, and its variation for the modular Hamiltonian. The bulk fields contributing to the canonical energy are defined via the HKLL procedure. In terms of CFT variables, the contribution of each such bulk field to the modular Hamiltonian is given by the OPE block corresponding to the dual operator integrated along the vacuum modular flow. These results do not rely on assuming large N or other special properties of the CFT and therefore they are purely kinematic.

 

Past Seminars