This series consists of talks in the area of Superstring Theory.
String-like objects arise in many quantum field theories.
Well known examples include flux tubes in QCD and cosmic strings. To a first approximation,
their dynamics is governed by the Nambu-Goto action, but for QCD flux tubes
numerical calculations of the energy levels of these objects have become so
accurate that a systematic understanding of corrections to this simple
description is desirable.
The entanglement entropy S(R) across a circle of radius R
has been invoked recently in deriving general constraints on renormalization
group flow in three-dimensional field theory.
At conformal fixed points, the negative of the finite part of the
entanglement entropy, which is called F, is equal to the free energy on the
round three-sphere. The F-theorem states that F decreases under RG flow.
Integrability has been successfully used to compute the
non-perturbative spectrum, Wilson loops and scattering amplitudes in the
AdS/CFT correspondence. Most of these results apply to N=4, D=4 SYM / strings
on AdS(5)xS(5). Strings on AdS(3)xM, where M is either
We derive the collective theory of singlet fields of large-N Sp(N) spin
models and display its unconventional features. Using the known relationship
between O(N) collective fields and higher spin fields of Vasiliev theory in AdS
space, we argue that the unique features of the Sp(N) collective
theory suggest an interpretation in terms of a higher spin theory in de Sitter
space, as proposed by Anninos, Hartman and Strominger. This is
reminiscent of the way the Liouville mode is naturally interpreted as
When nuclear matter is heated beyond a temperature of 2 trillion
degrees, it converts into a strongly coupled plasma of quarks and
gluons, the sQGP. Experiments using highly energetic collisions
between heavy nuclei have revealed that this new state of matter is a
nearly ideal, highly opaque liquid. A description based upon string
theory and black holes in five dimensions has made the quark- gluon
plasma an iconic example of a strongly coupled quantum system. In this
Knowledge of all-alpha' higher derivative corrections to leading order BPS and non-BPS brane actions would serve in future endeavor of determining the complete form of the non-abelian BPS and tachyonic effective actions. In this talk, we note that there is a universality in the all-alpha' order corrections to BPS and non-BPS branes. I talk about computing all amplitudes between one Ramond-Ramond C-field vertex operator and several SYM gauge/scalar vertex operators.
We add a gravitational background lattice to the simplest holographic model of matter at finite density and calculate the optical conductivity. With the lattice, the zero frequency delta function found in previous calculations (resulting from translation invariance) is broadened and the DC conductivity is finite. The optical conductivity exhibits a Drude peak with a cross-over to power-law behavior at higher frequencies. Surprisingly, these results bear a strong resemblance to the properties of some of the cuprates.