Lien Zoom: https://umontreal.zoom.us/j/93026432919
Meeting ID: 930 2643 2919
Passcode: écrire en chiffre: un, trois, sept.
First presentation:
Masques et filtration, les membranes qui font le travail
Masks and filtration, the membranes that do the trick
Jacques Lengaigne
Département de génie mécanique
École de technologie supérieure
Présentation en anglais, visuel en français
Résumé: Le masque, toujours dans notre face, littéralement... Comment cette technologie d’apparence si anodine s’est-elle imposée dans notre vie de tous les jours? Dans cette courte conversation, je vais tenter de vous présenter la vie intime du masque: des mécanismes de filtration aux défis de la fabrication auxquels nous faisons face pour approvisionner le monde. Sans conspiration, presque pas de politique, surtout de l’ingénierie, une pincée de science, venez pour une trempette dans la mare des textiles de commodités.
Abstract: The ubiquitous mask, always in our face, literally... How does this seemingly simple piece of technology has secured a place in our everyday life? In this short talk, I will present the inner life of the mask: from the simple working principles of filtration to the manufacturing hurdles we face to supply the world. No conspiracy, minimal politics, mostly engineering, a touch of science, come for a dive in the world of commodity textiles.
Second presentation:
Oxygen hole doping and superconductivity in the three-band Hubbard model
Sidhartha Dash
Département de physique
Université de Sherbrooke
Présentation en anglais
Abstract: The one-band Hubbard model describes quite well various aspects of the cuprate superconductors. However, it does not take into account the oxygen orbitals explicitly and hence cannot explain the experimental observations related to oxygen hole doping. For instance, Rybicki et al. [1] have shown that the superconducting critical temperature (T_c) is correlated with the hole content on the oxygen orbitals. In this talk, I will present our recent work on the three-band Hubbard model, which is a more accurate model for cuprates, using cluster dynamical mean field theory (CDMFT) at zero temperature with exact diagonalization (ED) impurity solver. We start with realistic values of band parameters from Weber et al. [2] and explore different parameter-sets. We observe that the superconducting order parameter at optimal doping is monotonously related to the corresponding oxygen hole doping and the charge-transfer gap, in the parameter regime relevant to cuprates. We also show indications that pairing in the three-band model is mediated by short-range antiferromagnetic interactions as is also known for the one-band Hubbard model.
- Rybicki, Damian, et al. 'Perspective on the phase diagram of cuprate high-temperature superconductors.' Nature communications 7.1 (2016): 1-6.
- Weber, Cédric, et al. 'Scaling of the transition temperature of hole-doped cuprate superconductors with the charge-transfer energy.' EPL (Europhysics Letters) 100.3 (2012): 37001.
Cette conférence est présentée par le RQMP.
