Nuclear and Particle Theory Seminar
Mondays, 1:00pm
MIT Center for Theoretical Physics
Organizers: Johannes Michel, Phiala Shanahan, Tracy Slatyer, Xiaojun Yao
January 31, 2022
Mikhail Ivanov, IAS
Title: Love and Naturalness
Abstract: It has been known for a decade that black holes are the most rigid objects in the universe: their tidal deformations (Love numbers) vanish identically in general relativity in four dimensions. This has represented a naturalness problem in the context of classical worldline effective field theory. In my talk I will present a new symmetry of general relativity (Love symmetry) that resolves this naturalness paradox. I will show that perturbations of rotating black holes enjoy an SL(2,R) symmetry in the suitable defined near zone approximation. This symmetry, while approximate in general, in fact yields exact results about static tidal deformations. This symmetry also implies that generic regular black hole perturbations form infinite-dimensional SL(2,R) representations, and in some special cases these are highest weight representations. It is the structure of these highest weight representations that forces the Love numbers to vanish. All other facts about Love numbers also acquire an elegant explanation in terms of SL(2,R) representation theory.
February 7, 2022
TBA
February 14, 2022
Isabel Garcia Garcia, University of California, Santa Barbara
TBA
February 21, President’s Day Holiday No Seminar
February 28, 2022
Siddharth Mishra-Sharma
Title: Dark photon oscillations in our inhomogeneous Universe and their imprint on CMB, radio, and 21-cm observations
Abstract: Kinetically-mixed dark photons can oscillate to Standard Model photons, and vice versa. These oscillations can be resonantly enhanced when the plasma mass of the Standard Model photon, which tracks the cosmic electron number density, matches the dark photon mass. I will present an analytic formalism for computing the effect of dark photon oscillations taking into account inhomogeneities in the plasma mass in our Universe and use this to derive new bounds on ultralight dark photons from spectral distortions of the CMB. I will then discuss how dark photon-to-photon oscillations could imprint themselves on observations of the redshifted 21-cm hydrogen line. Finally, I will motivate a possible connection to the long-standing radio background excess measured by ARCADE and low-frequency radio observations.
March 7, 2022
Clara Murgui, CalTech
“DarkUnification: a UV complete theory for asymmetric dark matter”.
Abstract:
March 14, 2022
Alessandro Lovato, ANL
Quantum Monte Carlo calculations of atomic nuclei and infinite neutron matter
Abstract
Understanding how the structure and dynamics of nuclei and infinite nuclear matter emerge from the individual interactions between neutrons and protons is a long-standing goal of nuclear theory. Solving the many-body Schrödinger equation involves non-trivial difficulties due to the non-perturbative nature and spin-isospin dependence of nuclear forces. Quantum Monte Carlo methods tackle this problem using stochastic techniques and accurately model short- and long-range nuclear dynamics. In this talk, I will present our recent calculations of the electroweak responses of atomic nuclei and matrix elements relevant to neutrino-less double-beta decay searches. I will then discuss the equation of state of infinite neutron matter, as obtained from local, chiral interactions that explicitly account for the excitation of the Delta resonance. Finally, I will provide some prospects on using artificial neural networks to compactly represent the wave functions of atomic nuclei and translational-invariant systems.
March 21, 2022 Spring Break (no seminar)
March 28, 2022
Francesca Cuteri, University of Frankfurt
Lattice insight into the QCD phase diagram at zero and nonzero (isopin) density
April 4, 2022
Aditya Pathak, University of Manchester
“A new paradigm for precision top mass measurement: Weighing the top with energy correlators”
April 11, 2022
Peter Denton, BNL
Light Dark Matter and Black Holes
April 18,2022 Patriot’s Day (no seminar)
April 25, 2022
Nobuo Sato, JLAB
The Next generation of QCD global analysis
May 2, 2022
Jamie Karthein, MIT
“Characterizing the Transition Region of the QCD Phase Diagram.”
May 9, 2022
Adrien Florio, Stony Brook
Dynamics of the O(4) critical point in QCD