944 research outputs found

### Two loop partition function for large N pure Yang-Mills theory on a small three-sphere

We give a direct path-integral calculation of the partition function for pure
3+1 dimensional U(N) Yang-Mills theory at large N on a small three-sphere, up
to two-loop order in perturbation theory. From this, we calculate the one-loop
shift in the Hagedorn/deconfinement temperature for the theory at small volume,
finding that it increases (in units of the inverse sphere radius) as we go to
larger coupling (larger volume). Our results also allow us to read off the sum
of one-loop anomalous dimensions for all operators with a given engineering
dimension in planar Yang-Mills theory on R^4. As checks on our calculation, we
reproduce both the Hagedorn shift and some of the anomalous dimension sums by
independent methods using the results of hep-th/0412029 and hep-th/0408178. The
success of our calculation provides a significant check of methods used in
hep-th/0502149 to establish a first order deconfinement transition for pure
Yang-Mills theory on a small three-sphere.Comment: 40 pages, 4 figures, harvma

### The Gravity Dual of a Density Matrix

For a state in a quantum field theory on some spacetime, we can associate a
density matrix to any subset of a given spacelike slice by tracing out the
remaining degrees of freedom. In the context of the AdS/CFT correspondence, if
the original state has a dual bulk spacetime with a good classical description,
it is natural to ask how much information about the bulk spacetime is carried
by the density matrix for such a subset of field theory degrees of freedom. In
this note, we provide several constraints on the largest region that can be
fully reconstructed, and discuss specific proposals for the geometric
construction of this dual region.Comment: 19 pages, LaTeX, 8 figures, v2: footnote and reference adde

### Nonlocal multi-trace sources and bulk entanglement in holographic conformal field theories

We consider CFT states defined by adding nonlocal multi-trace sources to the
Euclidean path integral defining the vacuum state. For holographic theories, we
argue that these states correspond to states in the gravitational theory with a
good semiclassical description but with a more general structure of bulk
entanglement than states defined from single-trace sources. We show that at
leading order in large N, the entanglement entropies for any such state are
precisely the same as those of another state defined by appropriate
single-trace effective sources; thus, if the leading order entanglement
entropies are geometrical for the single-trace states of a CFT, they are
geometrical for all the multi-trace states as well. Next, we consider the
perturbative calculation of 1/N corrections to the CFT entanglement entropies,
demonstrating that these show qualitatively different features, including
non-analyticity in the sources and/or divergences in the naive perturbative
expansion. These features are consistent with the expectation that the 1/N
corrections include contributions from bulk entanglement on the gravity side.
Finally, we investigate the dynamical constraints on the bulk geometry and the
quantum state of the bulk fields which must be satisfied so that the entropies
can be reproduced via the quantum-corrected Ryu-Takayanagi formula.Comment: 60 pages + appendices, 7 figures; v2: minor additions, published
versio

### Nonlinear Gravity from Entanglement in Conformal Field Theories

In this paper, we demonstrate the emergence of nonlinear gravitational
equations directly from the physics of a broad class of conformal field
theories. We consider CFT excited states defined by adding sources for scalar
primary or stress tensor operators to the Euclidean path integral defining the
vacuum state. For these states, we show that up to second order in the sources,
the entanglement entropy for all ball-shaped regions can always be represented
geometrically (via the Ryu-Takayanagi formula) by an asymptotically AdS
geometry. We show that such a geometry necessarily satisfies Einstein's
equations perturbatively up to second order, with a stress energy tensor
arising from matter fields associated with the sourced primary operators. We
make no assumptions about AdS/CFT duality, so our work serves as both a
consistency check for the AdS/CFT correspondence and a direct demonstration
that spacetime and gravitational physics can emerge from the description of
entanglement in conformal field theories.Comment: 55 pages, 8 figure

### Quality assessments of untreated and washed quinoa (Chenopodium quinoa) seeds based on histlogical and foaming capacity investigations

Quinoa seed has a high nutritional value, but has a coating of bitter-tasting saponins, making it unpalatable. Therefore the seeds are usually processed in order to remove the naturally occurring saponins from the seeds. To investigate the impact of processing, untreated and washed seeds of the white and brown types of quinoa were investigated histologically and by foaming capacity evaluations. Reference samples of known origin and treatment were investigated as well as unknown samples. The results revealed a relationship between the presence of saponin containing papillose cells at the outermost layer of the seed hull in the histological sections and the foaming capacity of the seeds. After washing, the papillose cells were severely damaged or completely removed and virtually no foam formation was observed. This investigation indicatedthat washing resulted in an effective removal of the saponin layer, leading to quality improvement of the seeds intended for human and animal consumption. The same features were observed for the unknown samples. These results imply that the treatment of the investigated samples was based on washing. The determination of the type of treatment applied provided useful information for the correct tax classification for Custom purposes

### Generally Covariant Actions for Multiple D-branes

We develop a formalism that allows us to write actions for multiple D-branes
with manifest general covariance. While the matrix coordinates of the D-branes
have a complicated transformation law under coordinate transformations, we find
that these may be promoted to (redundant) matrix fields on the transverse space
with a simple covariant transformation law. Using these fields, we define a
covariant distribution function (a matrix generalization of the delta function
which describes the location of a single brane). The final actions take the
form of an integral over the curved space of a scalar single-trace action built
from the covariant matrix fields, tensors involving the metric, and the
covariant distribution function. For diagonal matrices, the integral localizes
to the positions of the individual branes, giving N copies of the single-brane
action.Comment: 34 pages, LaTeX. v2: comments and refs adde

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