IPM Calendar 
Thursday 28 March 2024   Today  
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 ...