Events at Physics

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Events During the Week of May 30th through June 6th, 2021

Monday, May 31st, 2021

No events scheduled

Tuesday, June 1st, 2021

No events scheduled

Wednesday, June 2nd, 2021

Physics ∩ ML Seminar
Deep Neural Networks for Ab Initio Quantum Chemistry
Time: 11:00 am
Place: Online Seminar: Please sign up for our mailing list at for zoom link
Speaker: David Pfau, Deepmind
Abstract: In this talk, I will present work on how ideas from the machine learning community can give back to computational physics, in particular deep neural networks and approximate natural gradient descent. I will present a novel deep neural network architecture, the Fermionic Neural Network (FermiNet), which can be used as an expressive class of approximate solutions (Ansätze) to the Schrödinger equation for many-electron systems. We optimize the FermiNet by Kronecker-Factorized Approximate Curvature (KFAC), an approximation to natural gradient descent which can also be used to approximate stochastic reconfiguration. This makes it possible to scale stochastic reconfiguration to Ansätze with large numbers of parameters. We show that the FermiNet is able to achieve much higher accuracy than standard variational QMC Ansätze like the Slater-Jastrow-backflow ansatz, and can exceed the accuracy of coupled cluster methods like CCSD(T) on bond-breaking systems like the transition of bicyclobutane to butadiene. This shows that deep neural networks can be used to greatly improve the accuracy of variational QMC, to the point where it is competitive with other state-of-the-art ab initio methods.
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Thursday, June 3rd, 2021

Thesis Defense
Time: 10:30 am
Speaker: Ariel Rock, Physics PhD Graduate Student
Abstract: Abstract: The use of symmetry has been fundamental in the development of the Standard Model, and we continue to be guided by symmetric considerations in building BSM theories of supersymmetry breaking and flavor. We analyze a minimal flavored gauge mediation model of supersymmetry breaking in which the electroweak Higgs and messenger doublets mix as multiplets of a discrete non-Abelian symmetry given by the group S3. We show that in a specific limit, sizable stop mixing and flavor diagonal soft supersymmetry breaking parameters are achieved. In most of the parameter space, the masses of the colored superpartners are at most in the 5–6 TeV range. We show that couplings at the renormalizable level do not lead to viable quark mixing parameters, requiring the inclusion of higher-dimensional operators. As a concrete exploration of this idea, we show that the Cabibbo angle can be generated within this framework via such couplings and explore the scenario’s phenomenological implications. In a separate direction, we also explore the effects of correlations among observable parameters of neutrino mixing on predictions for the leptonic Dirac CP-violating phase. Focusing on a standard class of theoretical models of neutrino mixing governed by discrete non-Abelian symmetries corrected by a single charged lepton rotation, we show that we can guarantee a physically meaningful prediction for the most likely value of the leptonic Dirac CP-violating phase. Zoom link: Meeting ID: 959 7515 6310 Passcode: 308679
Host: Lisa Everett, Faculty Advisor
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Cosmology Journal Club
Time: 12:00 pm
Abstract: Each week, we start with a couple scheduled 15 minute talks about one's research, or an arXiv paper. The last 30 minutes will typically be open to the group for anyone to discuss an arXiv paper.

All are welcome and all fields of cosmology are appropriate.

Contact Ross Cawthon, cawthon@wisc, for more information.

Zoom info
Meeting ID: 93592708053, passcode: cmbadger

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Friday, June 4th, 2021

No events scheduled