IPM Calendar 
Saturday 26 September 2020   Today  
Events for day: Wednesday 16 September 2020    
           11:00 - 12:00     Online Computational Nanoscience journal club
Resonant Photovoltaic Effect in Doped Magnetic Semiconductors


Resonant Photovoltaic Effect in Doped Magnetic Semiconductors


The rectified nonlinear response of a clean, time-reversal symmetric, undoped semiconductor to an ac electric field includes a well known intrinsic shift current. We show that when Kramers degeneracy is broken, a distinct second order rectified response appears due to Bloch state anomalous velocities in a system with an oscillating Fermi surface. This effect, which we refer to as the resonant photovoltaic effect, produces a resonant galvanic current peak at the interband absorption threshold in doped semiconductors or semimetals with ap ...

           11:00 - 12:00     Wednesday Weekly Seminar-skyroom
Constraining the top quark effective field theory using the top quark pair production in association with a jet at future lepton colliders


Abstract: Our main aim in this paper is to constrain the effective field theory describing the top quark couplings through the e?e+?tt~+jet process. The analysis is carried out considering two different center-of-mass energies of 500 and 3000 GeV including a realistic simulation of the detector response and the main sources of background processes. The expected limits at 95% CL are derived on the new physics couplings such as tt~gamma, tt~Z, and tt~g for each benchmark scenario using the dileptonic tt~ final state. We show that the 95% CL limits on dimensionless Wilson coefficients considered in this analysis could be probed down to 10?4.

           14:00 - 15:00     Weekly Seminar
Condensed Matter and Statistical Physics Group
Reverse Dance in an External Flow: Meet Onsager again!



A driven fan that spins to create a flow of air would conversely rotate, if we turn it off, and subject it to a strong external flow. This is a classic example of reciprocity between cause and effect, in a life scale experiment. In small scale hydrodynamics, however, when the Reynolds number is quite low, a swimmer (pump) would generate a net motion (flow) only if its constructing parts non-trivially follow a pattern of motion which breaks time reciprocity. Here, considering a simple and well-controlled system of two micron-sized beads, we investigate if the mentioned exchange of physical cause and effect also holds ...

           15:30 - 17:30     Mathtematical Logic Weekly Seminar
Tameness for Set Theory


We show that (assuming large cardinals) set theory is a tractable (and we dare to say tame) first order theory when formalized in a first order signature with natural predicate symbols for the basic definable concepts of second and third order arithmetic, and appealing to the model-theoretic notions of model completeness and model companionship. Specifically we develop a general framework linking generic absoluteness results to model companionship and show that (with the required care in details) a $Pi_2$-property formalized in an appropriate language for second or third order number theory is forcible from some T extending ZFC + large car ...

           16:00 - 19:00     Thesis Defense
Neural representation of familiar faces in human visual cortex


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