Friday 29 March 2024 |
Events for day: Wednesday 18 April 2018 |
11:00 - 12:00 Computational nanoscience group biweekly journal club The Bethe-Salpeter equation in chemistry: relations with TD-DFT, applications and challenges School NANO SCIENCES The Bethe-Salpeter equation in chemistry: relations with TD-DFT, applications and challenges We review the many-body Green's function Bethe-Salpeter equation (BSE) formalism that is rapidly gaining importance for the study of the optical properties of molecular organic systems. We emphasize in particular its similarities and differences with time-dependent density functional theory (TD-DFT), both methods sharing the same formal O(N4) computing time scaling with system size. By comparison with higher level wavefunction based methods and experimental results, the advantages of BSE over TD-DFT are presented, including an accura ... 13:30 - 15:00 Weekly Seminar Dark Matter Production in an Early Matter Dominated Era School ASTRONOMY We investigate dark matter (DM) production in an early matter dominated era where a heavy long-lived particle decays to radiation and DM. In addition to DM annihilation into and thermal DM production from radiation, we include direct DM production from the decay of the long-lived particle. In contrast to earlier treatments, the temperature dependence of the number of degrees of freedom in the Standard Model (SM) plasma is treated carefully. Besides the well-known cases of thermal hot and cold DM, additional regions of parameter space with the approximately correct DM relic density appear. ... 14:00 - 15:00 Weekly Seminar Condensed Matter and Statistical Physics Group Magnetic Quantum Ratchet Effect in Bilayer Graphene School PHYSICS Seminar Room (classroom A), Farmanieh Building, IPM ... 14:00 - 15:00 Weekly Seminar Magnetic Quantum Ratchet Effect in Bilayer Graphene School NANO SCIENCES Magnetic Quantum Ratchet Effect in Bilayer Graphene We consider the orbital effect of an in-plane magnetic field on electrons in bilayer graphene, deriving linear-in- field contributions to the low-energy Hamiltonian arising from the presence of either skew interlayer coupling or interlayer potential asymmetry, the latter being tunable by an external metallic gate. To illustrate the relevance of such terms, we consider the ratchet effect in which a dc current results from the application of an alternating electric field in the presence of an in-plane magnetic field and inversion-symmetry breaking. By comparison with recent ... 15:00 - 16:00 Weekly Seminar Complexity Growth in Anisotropic Einstein-Axion-Dilaton Gravity School PARTICLES AND ACCELERATORS In this work we study the complexity growth in the anisotropic Einstein-Axion-Dilaton Gravity using complexity = action(CA) and complexity = volume(CV)conjectures. We compute analytically the complexity growth rate and we find that the Lloyds bound does not saturate in this model and difference between the complexity growth rate and the Lloyds bound is proportional to pressure difference in the longitudinal and transverse directions. And also one can see that the Loyds bound is violated in large anisotropies. This violation is maybe connected to the violation of the Kovtun-Son-Starinets (KSS) bound on the shear viscosity to entropy density ra ... 15:30 - 17:00 Geometry and Topology Weekly Seminar Connectifying a Topological Space by Adding one Point School MATHEMATICS In 1924, P. Alexandroff proved that a locally compact $T_2$-space has a $T_2$ one-point compactification (obtained by adding a ``point at infinity'') if and only if it is non-compact. He also asked for characterizations of spaces which have one-point connectifications. Here, we consider one-point connectifications, and in analogy with Alexandroff's theorem, we show that in the realm of $T_i$-spaces ($i=3frac{1}{2},4,5$) a locally connected space has a one-point connectification if and only if it has no compact component. We explain how this theorem may be extended to the case $i=2$ and to the case $i=6$ under the set-theoretic assumption $m ... 16:00 - 18:00 Neuroimaging Journal Club Time-Resolved Decoding of Two Processing Chains during Dual-Task Interference School COGNITIVE SCIENCES Venue: School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Opposite the ARAJ, Artesh Highway, Tehran, Iran ... |