Search Talks

We investigate through non-equilibrium molecular dynamic simulations the flow of anomalous
fluids inside rigid nanotubes. Our results reveal an anomalous increase of the overall mass flux
for nanotubes with sufficiently smaller radii. This is explained in terms of a transition from a
single-file type of flow to the movement of an ordered-like fluid as the nanotube radius increases.
The occurrence of a global minimum in the mass flux at this transition reflects the competition
between the two characteristic length scales of the core-softened potential. Moreover, by increasing
further the radius, another substantial change in the flow behavior, which becomes more evident at
low temperatures, leads to a local minimum in the overall mass flux. Microscopically, this second
transition is originated by the formation of a double-layer of flowing particles in the confined
nanotube space. These nano-fluidic features give insights about the behavior of confined isotropic
anomalous fluids.

The remnant accretion disk formed in binaries involving neutron stars and/or black holes is a source of non-relativistic ejecta. This 'disk wind' is launched on a thermal and/or viscous timescale, and can provide an amount of material comparable to that in the dynamical ejecta. I will present recent work aimed at characterizing

the properties of these winds through time-dependent radiation-hydrodynamic simulations that include the relevant physics needed to follow the ejecta composition. I will focus on the effect of black hole spin and/or hypermassive neutron star lifetime on the disk wind, and on the interaction of the wind with the dynamical ejecta. I will also discuss the implications of these results for the optical/IR signal from these events, and for the origin of r-process elements in the Galaxy.

The talk will be based on a work in progress with Stefano Kovacs
(Dublin IAS) and Yuki Sato (Wits University). In a previous work
(arxiv:1310.0016) we have shown that,
in the M-theory regime (large N with the Chern-Simon level k fixed)
of the duality between ABJM theory and M-theory on AdS4 x S7/Zk,
certain monopole operators with large R charges on the gauge theory side
correspond to spherical membranes
(which is in general in non-BPS excited states) in the pp-wave matrix
model on the dual side.

Having in mind application to
the study of three point functions of the monopole operators
from the dual side, we study the BPS instanton equation
of the pp-wave matrix model. The instanton equation describes, for example,
a process in which a single spherical membrane splits into
two spherical membranes. Under a certain
approximation which is valid when the matrix size is large,
the instanton equation can be recast
into a three dimensional Laplace equation;
a time snapshot of the membrane configuration corresponds
to an equipotential surface of the solution of the Laplace equation.
In order to study the above mentioned splitting process,
we found that one has to introduce a special boundary condition
of the Laplace equation: one prepares two copies of
three dimensional space which are connected in a manner analogous
to Riemann surfaces. We will discuss an exact solution
of the Laplace equation under this boundary condition, and 
the corresponding instanton solution, in which a membrane splits into two.

It is not known how to explain the excess of matter over antimatter with the Standard Model.  This matter asymmetry can be accounted for in certain extensions of the Standard Model through the mechanism of electroweak baryogenesis (EWBG), in which the extra baryons are created in the early Universe during the electroweak phase transition.  In this talk I will review EWBG, connect it to theories of new physics beyond the Standard Model, and show that in many cases the new particles and interactions required for efficient EWBG can be discovered using existing and expected data from the LHC.

The cosmic microwave background contains a wealth of
information about cosmology as well as high energy physics. It tells
us about the composition and geometry of the universe, the properties
of neutrinos, dark matter, and even about the conditions in our
universe long before the cosmic microwave background was emitted.
After a brief review of what we may hope to learn from studies of the
cosmic microwave background about the early universe, I will review
measurements of the angular power spectrum of temperature
perturbations from the first 15.5 months of Planck data by the Planck
collaboration and by Renee Hlozek, David Spergel and myself. I will
then discuss the implications for the early universe of the recently
released Planck full mission data as well as the joint analysis
between BICEP/KeckArray and Planck.

In this talk I will describe recent work with Almheiri and Dong, where we proposed a connection between the emergence of bulk locality in AdS/CFT and the theory of quantum error correction. Bulk notions such as Bogoliubov transformations, location in the radial direction, and the holographic entropy bound all have natural CFT interpretations in the language of quantum error correction.  Time permitting, I will also discuss work in progress with Pastawski, Preskill, and Yoshida on a new class of stabilizer codes that explicitly realize many of the properties we argued the AdS/CFT error correcting code should have.