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Informal Talk on geometry of tensor networks (MERA) and AdS/CFT
Brian Swingle Brandeis University
PIRSA:14050150Some Exact Results for Conformal Field Theories in d>2
Zohar Komargodski Stony Brook University
PIRSA:14050137Phenomenology of charge order in underdoped cuprates
Andrea Allais Harvard University
PIRSA:14050147Effective field theory of two-dimensional nonrelativistic chiral superfluid
Sergej Moroz University of Washington
PIRSA:14050101Visualizing Quantum Matter
PIRSA:14050100
Effective theories of vortex lines
Riccardo Penco University of Pennsylvania
PIRSA:14050103Vortex lines are a distinctive feature of superfluids and are characterized by a very peculiar dynamics. In this talk, I will first discuss the behavior of vortex lines in a non-relativistic superfluids in the incompressible limit. I will then introduce an effective theory of vortex lines coupled to sound which applies to relativistic superfluids. I will conclude by briefly discussing the similarities between the effective theory for vortex lines and non-relativistic General Relativity.Quantum matter without quasiparticles
Subir Sachdev Harvard University
PIRSA:14050109Modern materials abound in systems to which the quasiparticle picture does not apply, and developing their theoretical description remains an important challenge in condensed matter physics. I will describe recent progress in understanding the dynamics of two systems without quasiparticles: (i) ultracold atoms in optical lattices, and (ii) the nematic quantum critical point of metals with applications to the `strange metal’ found in the high temperature superconductors. A combination of field-theoretic, holographic, and numerical methods will be used.Informal Talk on geometry of tensor networks (MERA) and AdS/CFT
Brian Swingle Brandeis University
PIRSA:14050150Brian Swingle obtained his PhD from MIT in 2011 and then moved to Harvard, where he is currently a Simons Fellow in condensed matter physics. Swingle is interested in the physics of quantum matter, and especially in the interface between condensed matter physics, quantum information science, and gravity and holography.Hydrodynamics and anomalies
Dam Thanh Son University of Chicago
PIRSA:14050107Recently its has been found that relativistic hydrodynamics requires modifications in the presence of quantum anomalies. We will follow the theoretical developments that leads to this discovery and look at modern applications of hydrodynamics with anomalies.What's wrong with Goldstone?
Hitoshi Murayama University of Tokyo
PIRSA:14050106Spontaneous Symmetry Breaking is a very universal concept applicable for a wide range of subjects: crystal, superfluid, neutron stars, Higgs boson, magnets, and many others. Yet there is a variety in the spectrum of gapless excitations even when the symmetry breaking patterns are the same. We unified all known examples in a single-line Lagrangian of the low-energy effective theory.Quantum Turbulence
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Carlo Barenghi Newcastle University
PIRSA:14050104This hour will be devoted to a description of quantum turbulence,that is turbulence in superfluids. The first talk (~20 minutes) will be given by Russell Donnelly. He will describe briefly the problem of classical turbulence and how turbulence in superfluids is different. The second talk will be given by Carlo Barenghi who will discuss progress in the simulation of quantum turbulence which is capable of suggesting insights so far inaccessible to experiment.From scale invariance to Lorentz symmetry
Sergey Sibiryakov McMaster University
PIRSA:14050136I will discuss the enhancement of space-time symmetries to Lorentz (rotation) invariance at the renormalization group fixed points of non-relativistic (anisotropic) field theories. Upon describing examples from the condensed matter physics, I will review the general argument for the stability of the infrared fixed points with the enhanced symmetry. Then I will focus on unitary field theories in (1+1) space-time dimensions which are invariant under translations, isotropic scale transformations and satisfy the requirement that the velocity of signal propagation is bounded from above. No a priori Lorentz invariance will be assumed. Still, I will prove that above properties are sufficient to ensure the existence of an infinite dimensional symmetry given by one or a product of several copies of conformal algebra. In particular, this implies presence of one or several Lorentz groups acting on the operator algebra of the theory. I will conclude by discussing the challenges in extending this result to higher space-time dimensions.Some Exact Results for Conformal Field Theories in d>2
Zohar Komargodski Stony Brook University
PIRSA:14050137Phenomenology of charge order in underdoped cuprates
Andrea Allais Harvard University
PIRSA:14050147In the past few years substantial evidence has been collected that points to coexistence of charge correlations with long range superconductivity in underdoped cuprate superconductors. In this talk I will review some of this evidence, then show that a charge density wave with precisely the same signatures is a natural instability of an antiferromagnetic metal, and finally derive some phenomenological consequences, with special focus on quantum oscillation experiments.Universal incoherent metallic transport
Sean Hartnoll Stanford University
PIRSA:14050102In an incoherent metal, transport is controlled by the collective diffusion of energy and charge rather than by quasiparticle or momentum relaxation. We explore the possibility of a universal bound D \gtrsim \hbar v_F^2 /(k_B T) on the underlying diffusion constants in an incoherent metal. Such a bound is loosely motivated by results from holographic duality, the uncertainty principle and from measurements of diffusion in strongly interacting non-metallic systems. Metals close to saturating this bound are shown to have a linear in temperature resistivity with an underlying dissipative timescale matching that recently deduced from experimental data on a wide range of metals. The phenomenology of universal incoherent transport is found to reproduce various further observations in strongly correlated metals, and motivates direct probes of diffusive processes and measurements of charge susceptibilities. We suggest that this bound may be responsible for the ubiquitous appearance of high temperature regimes in metals with T-linear resistivity.Effective field theory of two-dimensional nonrelativistic chiral superfluid
Sergej Moroz University of Washington
PIRSA:14050101Due to the current search of Majorana fermions, the physics of two-dimensional identical fermions with short-range p-wave interactions is of considerable interest. My talk will be about the effective theory of a chiral p+ip fermionic superfluid at zero temperature. This theory naturally incorporates the parity and time reversal violating effects such as the Hall viscosity and the edge current. I will present some applications of this theory such as the linear response to external electromagnetic and gravitational fields and the density profile of an isolated vortex. Finally, the dual gauge reformulation of this theory will be presented.Visualizing Quantum Matter
PIRSA:14050100Recently developed techniques allow imaging of electronic quantum matter directly at the atomic scale. I will introduce the basic principles and describe the set of observables available from these techniques. As examples, I will survey visualization of exotic forms of electronic quantum matter including heavy fermions, quantum critical electrons, topological surface states, electronic liquid crystals, and high temperature superconductors.