Dear all,

This is an announcement of next week's events:

Seminars:

Date: 09/06/2025 11:00
Speaker: Carlos García Canal (U. La Plata)
Title: Do you remember the brachistochrone?
Abstract: After recalling the classical problem of the brachistochrone, the problem of the quantum brachistochrone is introduced. By means of the decomplexification procedure the mathematical equivalence between both problems is analyzed. The time of passage for the quantum cases corresponding to Hermitian and PT-symmetric Hamiltonians is computed. The equivalence between classical and quantum dynamics allows one to connect the time of passage of the brachistochrone with measurements in electric resonant circuits coupled by a gyrator. Reflexion about the mentioned equivalence are included.

Date: 10/06/2025 12:00
Speaker: Kuldeep Deka (New York U., Abu Dha)
Title: Dark Matter Genesis in the Reheating Era
Abstract: The post-inflationary reheating era plays a pivotal role in shaping the thermal history of the Universe, yet its dynamics remain poorly understood. In this talk, I will examine how various reheating scenarios impact dark matter (DM) production, encompassing both thermal and nonthermal origins. Using general parametrizations for the Hubble expansion rate and the evolution of the Standard Model temperature, I will present a unified framework to study DM genesis—including freeze-out mechanisms (WIMPs, SIMPs, ELDERs, Cannibals) and freeze-in processes (both infrared and ultraviolet regimes). These dynamics can significantly alter the viable DM parameter space, enabling much heavier thermal DM candidates and extending the reach for light feebly interacting particles. I will highlight the interplay between theoretical predictions and experimental constraints, emphasizing how future searches could uncover distinctive imprints of DM production during reheating.

Date: 13/06/2025 11:00
Speaker: Andrija Rasovic (Toronto U.)
Title: RG Improvement of the Scalar Effective Potential in Finite Temperature Quantum Field Theory
Abstract: Stochastic gravitational wave (GW) backgrounds from first-order phase transitions are a compelling target for next-generation GW observatories, offering a novel probe of dark sectors with strong phase transitions. However, reliable theoretical predictions for the GW signal strength remain challenging, particularly beyond the high-temperature regime where standard techniques like dimensional reduction become unreliable. In this talk, we present the Optimized Partial Dressing (OPD) framework, a thermal mass resummation method that uses gap equation solutions inserted into the tadpole of the potential to systematically improve perturbative calculations of the finite-temperature effective potential without relying on high-temperature expansion. We will review how OPD controls perturbation theory at finite temperature and then introduce a self-consistent renormalization group (RG) improvement of the scalar potential within the OPD formalism. This RG improvement substantially reduces the scale dependence of physical quantities and improves the robustness of predictions for gravitational wave signals from cosmological phase transitions.

See you all there.