<p>Particle Physics Seminar Speaker: Bob Svoboda</p><p>Institution: </p><p>Title: Test entry</p><p>Host: Robin</p><p>Room: 285</p><p>Abstract: </p>
User:
High-Energy Seminars
Time:
1:30pm - 2:30pm
Send Reminder:
Yes - 0 days 4 hour 0 minutes before start
Description:
Joint Theory Seminar Speaker: Grant Remmen (UC Berkeley)
Title: Weak Gravity, Entropy, and Dyonic Black Holes
Host: Verhaaren
Room: 432
Abstract: I demonstrate that higher-dimension operators in the Einstein-Maxwell EFT contribute positively to the entropy of a black hole. This set of entropy inequalities mandates new positivity bounds on the Wilson coefficients. I will show that one of these conditions implies that the charge-to-mass ratio of an extremal black hole asymptotes to unity from above for increasing mass, thus satisfying the Weak Gravity Conjecture. I extend this result to multiple dimensions and to dyonic black holes in four dimensions, as well as show that it passes a number of nontrivial tests.
Particle Physics Seminar Speaker:Surjeet Rajendran
Institution: UC Berkeley
Title: Firewalls in General Relativity
Host: Kaloper
Room: 285
Abstract: We present spherically symmetric solutions to Einstein's equations which are equivalent to canonical Schwarzschild and Reissner-Nordstrom black holes on the exterior, but with singular (Planck-density) shells at their respective event and inner horizons. The locally measured mass of the shell and the singularity are much larger than the asymptotic ADM mass. The area of the shell is equal to that of the corresponding canonical black hole, but the physical distance from the shell to the singularity is a Planck length, suggesting a natural explanation for the scaling of the black hole entropy with area. The existence of such singular shells enables solutions to the black hole information problem of Schwarzschild black holes and the Cauchy horizon problem of Reissner-Nordstrom black holes. While we cannot rigorously address the formation of these solutions, we suggest plausibility arguments for how normal black hole solutions may evolve into such states. We also comment on the possibility of negative mass Schwarzschild solutions that could be constructed using our methods. Requirements for the non-existence of negative-mass solutions may put restrictions on the types of singularities allowed in an ultraviolet theory of gravity.
User:
High-Energy Seminars
Time:
1:30pm - 2:30pm
Send Reminder:
Yes - 0 days 4 hour 0 minutes before start
Description:
<p>Joint Theory Seminar Speaker: Anders Andreassen<br />mail: aja@lbl.gov<br />Title: JUNIPR: a Framework for Unsupervised Machine Learning in Particle Physics<br />Host: Verhaaren<br />Room: 432<br />Abstract: In applications of machine learning to particle physics, a persistent challenge is how to go beyond discrimination to learn about the underlying physics. In this talk, we will present a new framework: JUNIPR, Jets from UNsupervised Interpretable PRobabilistic models, which uses unsupervised learning to learn the intricate high-dimensional contours of the data upon which it is trained, without reference to pre-established labels. In order to approach such a complex task, JUNIPR is structured intelligently around a leading-order model of the physics underlying the data. In addition to making unsupervised learning tractable, this design actually alleviates existing tensions between performance and interpretability. Applications to discrimination, data-driven Monte Carlo generation and reweighting of events will be discussed. </p>
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