Fine Theoretical Physics Institute Seminar

semester, 2018


Monday, January 29th 2018
3:30 pm:
FTPI Special Seminar in Tate 301-20
Speaker: Maxim Pospelov
Subject: "Widening the net in search for New Physics"
Candidate for FTPI Faculty Position

Following spectacular confirmation of the Standard Model at the LHC, the emphasis of particle physics shifts towards searches for physics beyond Standard Model. The clues for new physics may be hidden in cosmological data that suggest the dominance of dark matter and dark energy throughout the Universe. I will describe some recent aspects of widening the search for new physics focussing on light dark matter and in general on light weakly coupled states. I will introduce constraints on dark matter - electron scattering that result from a new phenomenon, the reflection of dark matter from the solar interior. I will also argue that besides conventional probes of light weakly coupled states, further insight can be gained by involving precision AMO tools, and describe some recent experimental activity in this direction.

Faculty Host: Keith Olive

Tuesday, January 30th 2018
1:00 pm:
FTPI Special Seminar in Tate 201-20
Speaker: Maxim Pospelov
Subject: "Light Z' coupled to poorly conserved currents"
Candidate for FTPI Faculty Position
Faculty Host: Keith Olive

Monday, February 12th 2018
3:30 pm:
Speaker: Katherine Freese
Subject: The Dark Matter in the Universe
Candidate for FTPI Faculty Position

“What is the Universe made of?” This question is the longest outstanding problem in all of modern physics, and it is one of the most important research topics in cosmology and particle physics today. The bulk of the mass in the Universe is thought to consist of a new kind of dark matter particle, and the hunt for its discovery in on. I'll start by discussing the evidence for the existence of dark matter in galaxies, and then show how it fits into a big picture of the Universe containing 5% atoms, 25% dark matter, and 70% dark energy. Neutrinos only constitute ½% of the content of the Universe, but much can be learned about neutrino properties from cosmological data. Leading candidates for the dark matter are Weakly Interacting Massive Particles (WIMPs), axions, and sterile neutrinos. WIMPs are a generic class of particles that are electrically neutral and do not participate in strong interactions, yet have weak-scale interactions with ordinary matter. There are multiple approaches to experimental searches for WIMPS: at the Large Hadron Collider at CERN in Geneva; in underground laboratory experiments; with astrophysical searches for dark matter annihilation products, and upcoming searches with the James Webb Space Telescope for Dark Stars, early stars powered by WIMP annihilation. Current results are puzzling and the hints of detection will be tested soon. At the end of the talk I'll briefly turn to dark energy and its effect on the fate of the Universe.

Faculty Host: Keith Olive

Tuesday, February 13th 2018
1:00 pm:
FTPI Special Seminar in Tate 201-20
Speaker: Katherine Freese
Subject:  Inflationary Cosmology: Theoretical Developments and Status in light of Cosmic Microwave Background Data
Candidate for FTPI Faculty Position
Faculty Host: Keith Olive

Monday, February 19th 2018
3:30 pm:
Speaker: Mithat Unsal
Subject: Decoding path integrals: Resurgence and mass gap
Candidate for FTPI Faculty Position

I will provide an introductory level overview of recent
applications of resurgent trans-series and Picard-Lefschetz theory to
quantum mechanics and quantum field theory.
Resurgence connects local perturbative data with global topological
structures. In quantum mechanical systems, this program provides a
constructive relation between different saddles. For example, in
certain cases it has been shown that all information around the
instanton saddle is encoded in perturbation theory around the
perturbative saddle. In quantum field theory, such as sigma-models
compactified on a circle, neutral bions provide a semi-classical
interpretation of the elusive IR-renormalon, and fractional kink
instantons lead to the non-perturbatively induced mass gap exactly of
order of the strong scale. I also describe the concept of hidden
topological angle, a phase associated with Lefschetz thimbles.
Hidden topological angle may provide destructive/constructive
interference effects between equally dominant saddles in the Lefschetz
thimble decomposition, providing resolution to some time standing
puzzles in non-perturbative analysis.

Faculty Host: Keith Olive

Tuesday, February 20th 2018
1:00 pm:
FTPI Special Seminar in Tate 201-20
Speaker: Mithat Unsal
Subject: Phase transitions, semi-classics and anomalies
Candidate for FTPI Faculty Position
Faculty Host: Keith Olive

Monday, September 24th 2018
2:00 pm:
FTPI Seminar in Physics 301-20
Speaker: Alexander Monin
Subject: EFT for CFT with large charge

In a generic conformal field theory the spectrum of operators carrying a large U(1) charge can be analyzed semiclassically. The key is the operator state correspondence by which such operators are associated with a finite density superfluid phase for the theory quantized on the cylinder. The dynamics is dominated by the corresponding Goldstone hydrodynamic mode and the derivative expansion coincides with the inverse charge expansion. I will illustrate this situation by first considering simple quantum mechanical analogues and then will systematize the approach by employing the coset construction for non-linearly realized space-time symmetries. Focussing on a 3-dimensional theory I will illustrate that the three point function coefficients turn out to satisfy universal scaling laws and correlations as the charge and spin are varied. Lastly I’ll show how the approach can be generalized to the case of large spin by considering vortices in the superfluid.


Wednesday, October 3rd 2018
7:00 pm:
Misel Public Lecture in McNamara Alumni Center, Memorial Hall
Speaker: Professor Nergis Mavalvala, Massachusetts Institute of Technology
Subject: Gravitational Waves: A New Window to the Universe

Recent announcements of the first ever detections of gravitational waves from colliding black holes and neutron stars have launched a new era of gravitational wave astrophysics. I will describe the science, technology, and human story behind these discoveries that provide a completely new window into some of the most violent and warped events in the Universe.


Monday, December 3rd 2018
12:30 pm:
FTPI Seminar in Tate 301-20
Speaker: Alexander Turbiner
Subject: Choreography in (non)-Newtonian gravity

By definition the choreography (dancing curve) is the trajectory
on which n classical bodies move chasing each other without collisions.
The first choreography (the remarkable Figure Eight) at zero angular
momentum was discovered unexpectedly by C Moore (Santa Fe) at 1993
for 3 equal mass bodies in R^3 Newtonian gravity numerically.
At the moment about 6,000 choreographies are known, all numerically
in Newtonian gravity. A number of 3-body choreographies is known
for Lenard-Jones potential again numerically.

Do exist (non)-Newtonian gravity for which dancing curve is known
analytically? - Yes, one example is known - it is algebraic lemniscate by
Jacob Bernoulli (1694) - and it will be the subject of the talk.
Astonishingly, Newtonian Figure Eight coincides with algebraic lemniscate
with accuracy 10 - 7 .

Faculty Host: Mikhail Shifman

Monday, December 10th 2018
12:30 pm:
FTPI Seminar in Tate 301-20
Speaker: Pavel Pylyavskyy, University of Minnesota, Dept. of Mathematics
Subject: Ising model and the positive orthogonal Grassmannian

Ising model is a classical model for ferromagnetism in statistical mechanics. In a joint work with Pavel Galashin we completely describe by inequalities the set of boundary correlation matrices of planar Ising networks embedded in a disk. Specifically, we give a simple bijection between such correlation matrices and points in the totally nonnegative part of the orthogonal Grassmannian, which has been introduced recently in the study of the scattering amplitudes of ABJM theory. Under our correspondence, Kramers--Wannier's high/low temperature duality transforms into the cyclic symmetry of the Grassmannian. We also show that the edge parameters of the Ising model for reduced networks can be uniquely recovered from boundary correlations, solving the inverse problem.

Faculty Host: Alex Kamenev

The weekly calendar is also available via subscription to the physics-announce mailing list, and by RSS feed.