11,385 research outputs found
The Covariant Quantum Superstring and Superparticle from their Classical Actions
We develop an approach based on the Noether method to construct nilpotent
BRST charges and BRST-invariant actions. We apply this approach first to the
holomorphic part of the flat-space covariant superstring, and we find that the
ghosts b, c_z which we introduced by hand in our earlier work, are needed to
fix gauge symmetries of the ghost action. Then we apply this technique to the
superparticle and determine its cohomology. Finally, we extend our results to
the combined left- and right-moving sectors of the superstring.Comment: 14 pages, harmva
Curved Beta-Gamma Systems and Quantum Koszul Resolution
We consider the partition function of beta-gamma systems in curved space of
the type discussed by Nekrasov and Witten. We show how the Koszul resolution
theorem can be applied to the computation of the partition functions and to
characters of these systems and find a prescription to enforce the hypotheses
of the theorem at the path integral level. We illustrate the technique in a few
examples: a simple 2-dimensional target space, the N-dimensional conifold, and
a superconifold. Our method can also be applied to the Pure Spinor constraints
of superstrings.Comment: harvmac, 17 page
Super-Chern-Simons Theory as Superstring Theory
Superstrings and topological strings with supermanifolds as target space play
a central role in the recent developments in string theory. Nevertheless the
rules for higher-genus computations are still unclear or guessed in analogy
with bosonic and fermionic strings. Here we present a common geometrical
setting to develop systematically the prescription for amplitude computations.
The geometrical origin of these difficulties is the theory of integration of
superforms. We provide a translation between the theory of supermanifolds and
topological strings with supertarget space. We show how in this formulation one
can naturally construct picture changing operators to be inserted in the
correlation functions to soak up the zero modes of commuting ghost and we
derive the amplitude prescriptions from the coupling with an extended
topological gravity on the worldsheet. As an application we consider a simple
model on R^(3|2) leading to super-Chern-Simons theory.Comment: hravmac, 50p
Fluctuating Initial Conditions and Anisotropic Flows
In this work we study the connection between anisotropic flows and lumpy
initial conditions for Au+Au collisions at 200GeV. We present comparisons
between anisotropic flow coefficients and eccentricities up to sixth order, and
between initial condition reference angles and azimuthal particle distribution
angles. We also present a toy model to justify the lack of connection between
flow coefficients and eccentricities for individual events.Comment: 5 pages, 3 figure
Primordial star formation: relative impact of H2 three-body rates and initial conditions
Population III stars are the first stars in the Universe to form at z=20-30
out of a pure hydrogen and helium gas in minihalos of 10^5-10^6 M .
Cooling and fragmentation is thus regulated via molecular hydrogen. At
densities above 10^8 cm, the three-body H2 formation rates are
particularly important for making the gas fully molecular. These rates were
considered to be uncertain by at least a few orders of magnitude. We explore
the impact of new accurate three-body H2 formation rates derived by Forrey
(2013) for three different minihalos, and compare to the results obtained with
three-body rates employed in previous studies. The calculations are performed
with the cosmological hydrodynamics code ENZO (release 2.2) coupled with the
chemistry package KROME (including a network for primordial chemistry), which
was previously shown to be accurate in high resolution simulations. While the
new rates can shift the point where the gas becomes fully molecular, leading to
a different thermal evolution, there is no trivial trend in how this occurs.
While one might naively expect the results to be inbetween the calculations
based on Palla et al. (1983) and Abel et al. (2002), the behavior can be close
to the former or the latter depending on the dark matter halo that is explored.
We conclude that employing the correct three-body rates is about as equally
important as the use of appropriate initial conditions, and that the resulting
thermal evolution needs to be calculated for every halo individually.Comment: 10 pages, 9 figures, A&A, 561, A13 (2014
Superstrings and WZNW Models
We give a brief review of our approach to the quantization of superstrings.
New is a covariant derivation of the measure at tree level and a path integral
formula for this measure.Comment: 12 pp, LaTeX, Contribution to the QTS3 Conference Proceeding
Fermionic Corrections to Fluid Dynamics from BTZ Black Hole
We reconstruct the complete fermionic orbit of the non-extremal BTZ black
hole by acting with finite supersymmetry transformations. The solution
satisfies the exact supergravity equations of motion to all orders in the
fermonic expansion and the final result is given in terms of fermionic
bilinears. By fluid/gravity correspondence, we derive linearized Navier-Stokes
equations and a set of new differential equations from Rarita-Schwinger
equation. We compute the boundary energy-momentum tensor and we interpret the
result as a perfect fluid with a modified definition of fluid velocity.
Finally, we derive the modified expression for the entropy of the black hole in
terms of the fermionic bilinears.Comment: 21 pages, Latex2e, no figure
Equations of the reaction-diffusion type with a loop algebra structure
A system of equations of the reaction-diffusion type is studied in the
framework of both the direct and the inverse prolongation structure. We find
that this system allows an incomplete prolongation Lie algebra, which is used
to find the spectral problem and a whole class of nonlinear field equations
containing the original ones as a special case.Comment: 16 pages, LaTex. submitted to Inverse Problem
Fermionic Wigs for BTZ Black Holes
We compute the wig for the BTZ black hole, namely the complete non-linear
solution of supergravity equations with all fermionic zero modes. We use a
"gauge completion" method starting from AdS_3 Killing spinors to generate the
gravitinos fields associated to the BH and we compute the back-reaction on the
metric. Due to the anticommutative properties of the fermionic hairs the
resummation of these effects truncates at some order. We illustrate the
technique proposed in a precedent paper in a very explicit and analytical form.
We also compute the mass, the angular momentum and other charges with their
corrections.Comment: 11 pages, no figure
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