Fine Theoretical Physics Institute Seminar

semester, 2014


Monday, March 10th 2014
Speaker: Gabriele Veneziano (College de France)
Subject: "Transplanckian collisions of particles, strings and branes"

I will give an overview on what we have learned so far on transplanckian-energy collisions of particles, strings, and branes, mention some open problems, and speculate on the lessons we may hope to draw in the near future from these gedanken experiments.


Friday, March 28th 2014
Speaker: Clifford Cheung (Caltech)
Subject: Naturalness and the Weak Gravity Conjecture

The weak gravity conjecture (WGC) asserts a powerful consistency condition on gauge theories coupled to quantum gravity: an Abelian, long-range force requires a state of charge q and mass m such that q>m/mPl. Failure of this condition implies the existence of stable black hole remnants and is in tension with no-hair theorems. In this paper, we argue that the WGC creates a non-perturbative obstruction to naturalness, which is the notion that dimensionless coefficients should take on (1) values in the absence of enhanced symmetry. As an illustration, we show that for scalar quantum electrodynamics, a natural spectrum can actually be forbidden by the WGC, which bounds a radiatively unstable quantity, m, by a radiatively stable quantity, q. More generally, the WGC can be at odds with naturalness in any theory containing charged fundamental scalars. We extend the conditions of the WGC to more complicated theories with multiple gauge symmetries and particles. Finally, we discuss implications for the hierarchy problem and construct a simple model in which the natural value of the electroweak scale - at the cutoff - is forbidden by the WGC.


Thursday, May 1st 2014
09:00 am:
Correlated Oxides and Oxide Interfaces workshop in Mississippi Room, Coffman Memorial Union

8:40 am
Registration

8:55 am
Welcome and opening Remarks
Martin Greven and Alex Kamenev
University of Minnesota

9:00 am
Quasiparticle thermalization and recombination in cuprate superconductors
Joseph Orenstein
University of California, Berkeley

9:30 am
Theory of nonlinear phononics for coherent light-control of solids
Antoine Georges
Collège de France

10:00 am
Searching for pairing interactions with coherent charge fluctuations spectrocopy
Jose Lorenzana
ISC-Sapienza, Rome

10:30 am
COFFEE BREAK

11:00 am
The cuprate phase diagram: new insights from neutron scattering and electrical transport
Mun Chan
University of Minnesota

11:30 am
Intrinsic Superconducting Phases in Single-layer Cuprates
Zhong-Xian Zhao
Institute of Physics, Chinese Academy of Sciences, Beijing

12:00 pm
The cuprate phase diagram from NMR
Jürgen Haase
Universitat Leipzig

12:30 pm
LUNCH BREAK

2:00 pm
Fermi Surface and Pseudogap Evolution in a Cuprate Superconductor
Jennifer Hoffman
Harvard University

2:30 pm
Fermi-surface-free Superconductivity in Bi2201
Robert Markiewicz
Northeastern University

3:00 pm
COFFEE BREAK

3:30 pm
The explicit Role of O states in high oxidation state strongly correlated oxides George Sawatzky
University of Brithish Columbia

4:00 pm
Design of correlated metals without inversion symmetry
James Rondinelli
Drexel University

4:30 pm
"Molecules" in solids and orbital-selective Peierls transition
Daniel Khomskii
Universitat zu Koln

5:00 pm
Workshop Ends for the Day


Friday, May 2nd 2014
09:00 am:

9:00 am
Search for hidden broken local symmetry states in correlated electron systems
Simon Billinge
Columbia University

9:30 am
Novel multiorbital magnetic insulators arising from the interplay of correlations and spin-orbit coupling
Nandini Trivedi
Ohio State University

10:00 am
COFFEE BREAK

10:30 am
Competing superexchange interactions in osmate double perovskites
Patrick Woodward
Ohio State University

11:00 am
Topolological 2DEG at the 111 surface of KTaO3
Marc Gabay
Université Paris-Sud

11:30 am
Topological Phases in Transition Metal Oxides
Gregory Fiete
University of Texas, Austin

12:00 pm
LUNCH BREAK

1:30 pm
Exotic magnetism produced by strong spin-orbit coupling in complex Ir oxides
Hidenori Takagi
Max Planck Institute and University of Tokyo

2:00 pm
Topological and Magnetic Phases with Strong Spin-Orbit Coupling in the Hyperhoneycomb Iridates
Yong-Baek Kim
University of Toronto

2:30 pm
Critical properties of the Kitaev-Heisenberg model
Natalia Perkins
University of Wisconsin, Madisson

3:00 pm
COFFEE BREAK AND POSTER SESSION

5:00 pm Workshop ends


Saturday, May 3rd 2014
09:00 am:

9:00 am
Reconstructions in Magnetic Oxide Heterostructures
Harold Hwang
Stanford University

9:30 am
Strong Electron Correlations in Oxide Quantum Wells
Susanne Stemmer
University of California, Santa Barbara

10:00 am
Emergent Magnetic Phenomena at Complex Oxide Interfaces
Yuri Suzuki
Stanford University

10:30 am
COFFEE BREAK

11:00 am
Local Electrostatic Imaging of Striped Domain Order in LaAlO3/SrTiO3
Shahal Ilani
Weizmann Institute

11:30 am
Magnetism of oxide interface LaAlO3/SrTiO3
Lu Li
University of Michigan

12:00 pm
Chiral magnetism at oxide interfaces and 2D materials
Mohit Randeria
Ohio State University

12:30 pm
LUNCH BREAK
Lunch is on your own.
Please refer to the dining guide in the back of this booklet for options.

2:00 pm
Orbital and Spin Order in t2g Two-Dimensional Electron Gases
Allan MacDonald
University of Texas at Austin

2:30 pm
Rashba Spin-Orbit Effect at the Oxide Interfaces
Sashi Satpathy
University of Missouri

3:00 pm
MBE Growth and Study of Electronic Transport of NdTiO3/SrTiO3 Heterostructures via Stoichiometry Control
Bharat Jalan
University of Minnesota

3:30 pm
COFFEE BREAK

4:00 pm
Critical dopings and superconducting domes in bulk SrTiO3
Kamran Behnia
ESPCI, Paris

4:30 pm
Metal-insulator transition in doped STO and puzzles of LAO/STO interface
Boris Shklovskii
University of Minnesota

5:00 pm
Understanding the Conductivity and Magnetism at Interfaces of Insulating Nomagnetic Oxides: The case of SrTiO3/LaAlO3
Liping Yu
University of Colorado

5:30 pm
Workshop ends for the day


Sunday, May 4th 2014
09:00 am:

9:00 am
Dimensional Confinement and Epitaxial Strain as Knobs for Manipulating Correlated Electronic States in Complex Oxide Thin Films
Kyle Shen
Cornell University

9:30 am
Complex Magnetotransport Phenomena in Ultra-Thin Film La0.5Sr0.5CoO3-d on SrTiO3
Chris Leighton
University of Minnesota

10:00 am
COFFEE BREAK

10:30 am
Magnetism and electronic reconstruction at interfaces probed by resonant soft x-ray spectroscopies
Giacomo Ghiringhelli
Politecnico di Milano

11:00 am
Understanding Interfaces as a Route to Control the Orbital Degree of Freedom in Cuprates
John Freeland
Argonne National Laboratory

11:30 am
Electrostatic Modification of Cuprate Superconductors
Allen Goldman
University of Minnesota

12:00 pm
Closing Remarks
TBA

12:45 pm
Workshop Closing
Thank you for your participation


Monday, May 19th 2014
Speaker: Boris Ermolaev - (Ioffe Institute)
Subject: “New Approach to QCD Factorization”

Friday, October 3rd 2014
Speaker: Peter Koroteev (Perimeter Institute)
Subject: Dualities in Five Dimensional Gauge Theories with Defects

We study various protected quantities in five dimensional gauge theories on \mathbb{R}^4\times S^1 with eight supercharges in the presence of defects. Surface defects can be described by a certain three dimensional quiver gauge theory on \mathbb{R}^2\times S^1, whose twisted chiral ring we extensively study by various methods including classical parameter spaces of supersymmetric vacua and exact partition functions. Three dimensional mirror symmetry and integrability of the dual spin chain play important roles in our analysis. For a coupled 5d/3d system we find a convenient description using monodromy defects along the two-plane which is orthogonal to the 3d defect. We compute the corresponding 5d ramified instanton partition function and show that it solves a system of difference equations of a certain elliptic integrable many-body system. We analyze various limiting cases of our construction and identify them with many previously known integrable models.


Friday, October 31st 2014
Speaker: Liam Fitzpatrick (Stanford U.)
Subject: Wilsonian and Large N approaches to Quantum Critical Metals

Monday, November 3rd 2014
Speaker: Alexander Gorsky
Subject: Baryons as Dyonic Instantons

Friday, November 7th 2014
Speaker: Florian Niedermann (Munich U.)
Subject: The Universe as a Cosmic String

We are investigating modifications of general relativity that are operative at the largest observable scales. In this context, we are investigating the model of brane induced gravity in 6D, a higher dimensional generalization of the DGP model. As opposed to different claims in the literature, we have proven the quantum stability of the theory on a linear level. In particular, we have shown that the Hamiltonian of the linear theory is bounded from below. This result opened a new window of opportunity for consistent modified Friedmann cosmologies. In our recent work it is shown that a brane with FRW symmetries necessarily acts as a source of cylindrically symmetric gravitational waves, so called Einstein-Rosen waves. Their existence essentially distinguishes this model from its codimension-one counterpart and necessitates to solve the non-linear system of bulk and brane-matching equations. A numerical analysis is performed and two qualitatively different and dynamically separated classes of cosmologies are derived: degravitating solutions for which the Hubble parameter settles to zero despite the presence of a non-vanishing energy density on the brane and super-accelerating solutions for which Hubble grows unbounded. The parameter space of both the stable and unstable regime is derived and observational consequences are discussed: It is argued that the degravitating regime does not allow for a phenomenologically viable cosmology. On the other hand, the super-accelerating solutions are potentially viable, however, their unstable behavior questions their physical relevance.


Friday, December 5th 2014
Speaker: Thomas Christian Bachlechner
Subject: CANCELLED, no seminar.

Monday, December 8th 2014
Speaker: Alexei Milekhin (ITEP)
Subject: RG-Whitham dynamics in Hamiltonian systems and resurgence phenomenon

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