IPM Calendar 
Thursday 4 March 2021   Today  
Events for day: Wednesday 03 February 2021    
           11:00 - 12:00     Wednesday Weekly Seminar-google meet
Vector Dark matter as a solution for hierarchy problem and first order phase transition


Abstract: In this talk, we introduce a conformal version of the Standard Model (SM), which apart from SM sector, containing a UD(1) dark sector with a vector dark matter candidate and a scalar field (scalon). In this model the dark sector couples to the SM sector via a Higgs portal. The theory is scale-invariant in lowest order, therefore the spontaneous symmetry breaking of scale invariance entails the existence of a scalar particle, scalon, with vanishing zeroth-order mass. However, one-loop corrections break scale invariance, so they give mass to the scalon. Because of the scale invariance, our model is subjected to constraints which remov ...

           13:30 - 15:00     Weekly Seminar (Online)
Primordial non-Gaussianity from galaxy statistics


The non-Gaussianity of the initial conditions leaves its imprints on the large scale structure. Upcoming galaxy redshift surveys such as DESI, EUCLID and SPHEREx, promise to significantly improve current limits on primordial non-Gaussianity through measurements of 2- and 3-point correlation functions in Fourier space. However, realizing the full potential of this dataset is contingent upon having both accurate theoretical models and optimized analysis methods. In the first of this talk, I will discuss my recent work on comparison of the theoretical predictions of the halo power spectrum and bispectrum, based on perturbation theory, against a ...

           14:00 - 15:00     Weekly Seminar
Condensed Matter and Statistical Physics Group
Rapid Progress of Perovskite Solar Cells: Reaching High Power Conversion Efficiency and Tackling Instabilities



Perovskite solar cells (PSCs) are presently attracting intense research interest due to their unprecedented development in solar radiation to electric power conversion efficiency (PCE) attaining a new certified record of 25.5%. This photovoltaic technology has demonstrated a great potential to provide solutions for a more sustainable future in energy supply. The PSCs use perovskites with an ABX3 structure where A is the monovalent cation (methylammonium (MA), Guanidium (GA), formamidinium (FA), rubidium (Rb), and/or cesium (Cs)), B is a divalent cation (Pb, and/or Sn) and X is a monovalent anion (typically a halogen ...

           15:30 - 17:30     Mathtematical Logic Weekly Seminar
A Definable Hamel Basis without Choice


In 2016, Beriashvili, Wu, Yu, and the speaker answered a long standing open question by showing that in the Cohen-Halpern-Levy model (which has an infinite set of reals without a countable subset, in particular, there is no well-order of the reals) there is a Hamel basis, i.e., a basis for the reals construed as a vector space over the rationals. In later joint work with Kanovei, we produced a variant of this model in which choice fails as badly and in which there is a (lightface Delta^1_3) definable Hamel basis. We produce these results and state interesting open questions. The talk will be accessible to a broad audience, no specific knowle ...