1,652 research outputs found
Non-Relativistic Superstrings: A New Soluble Sector of AdS_5xS^5
We find a new sector of string theory in AdS_5xS^5 describing
non-relativistic superstrings in that geometry. The worldsheet theory of
non-relativistic strings in AdS_5xS^5 is derived and shown to reduce to a
supersymmetric free field theory in AdS_2. Non-relativistic string theory
provides a new calculable setting in which to study holography.Comment: 29 pages, LATEX forma
A Note on Unitarity of Non-Relativistic Non-Commutative Theories
We analyze the unitarity of a non-relativistic non-commutative scalar field
theory. We show that electric backgrounds spoil unitarity while magnetic ones
do not. Furthermore, unlike its relativistic counterparts, unitarity can not be
restored (at least at the level of one-to-one scattering amplitude) by adding
new states to the theory. This is a signal that the model cannot be embedded in
a natural way in string theory.Comment: 6 pages, 2 figures. References adde
Holographic Gauge Theories in Background Fields and Surface Operators
We construct a new class of supersymmetric surface operators in N=4 SYM and
find the corresponding dual supergravity solutions. We show that the insertion
of the surface operator - which is given by a WZW model supported on the
surface - appears by integrating out the localized degrees of freedom along the
surface which arise microscopically from a D3/D7 brane intersection.
Consistency requires constructing N=4 SYM in the D7 supergravity background and
not in flat space. This enlarges the class of holographic gauge theories dual
to string theory backgrounds to gauge theories in non-trivial supergravity
backgrounds. The dual Type IIB supergravity solutions we find reveal - among
other features - that the holographic dual gauge theory does indeed live in the
D7-brane background.Comment: 42 pages, harvmac, corrected typo
Physical and chemical signatures of a developing anticyclonic eddy in the Leeuwin Current, eastern Indian Ocean
A multidisciplinary cruise aboard the R/V Southern Surveyor was conducted in May 2006 to sample a developing anticyclonic eddy of the Leeuwin Current off Western Australia. The eddy formed from a meander of the Leeuwin Current in mid-April 2006 and remained attached to the current until mid-August. In this study, a combination of satellite data (altimeter, sea surface temperature, and chlorophyll a) and shipboard measurements (acoustic Doppler current profiler and conductivity-temperature-depth) were used to characterize the physical and chemical signatures of the eddy. The temperature-salinity properties of the mixed layer waters within the anticyclonic eddy and on the shelf were both connected to that of the Leeuwin Current, indicating the water mass in the eddy is mainly derived from the Leeuwin Current and the modified Leeuwin Current water on the shelf. Above the salinity maximum near the eddy center, there was a regionally significant concentration of nitrate (>0.9 μmol L-1), and the maximum (2 μmol L-1) was at 150 in depth, below the photic zone. Nitrification within the eddy and/or local upwelling due to the forming eddy could be responsible for this high concentration of nitrate near the eddy center which potentially makes the eddy a relatively productive feature in the Leeuwin Current
BIons in topological string theory
When many fundamental strings are stacked together, they puff up into
D-branes. BIons and giant gravitons are the examples of such D-brane
configurations that arise from coincident strings. We propose and demonstrate
analogous transitions in topological string theory. Such transitions can also
be understood in terms of the Fourier transform of D-brane amplitudes.Comment: 21 pages; v.2 references added; v.3 reference added; v.4 minor
corrections; v.5 substantial rewritin
Vortex loop operators, M2-branes and holography
This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/ by/4.0/archiveprefix: arXiv primaryclass: hep-th reportnumber: HU-EP-08-43 slaccitation: %%CITATION = ARXIV:0810.4344;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: HU-EP-08-43 slaccitation: %%CITATION = ARXIV:0810.4344;%
`Stringy' Newton-Cartan Gravity
We construct a "stringy" version of Newton-Cartan gravity in which the
concept of a Galilean observer plays a central role. We present both the
geodesic equations of motion for a fundamental string and the bulk equations of
motion in terms of a gravitational potential which is a symmetric tensor with
respect to the longitudinal directions of the string. The extension to include
a non-zero cosmological constant is given. We stress the symmetries and
(partial) gaugings underlying our construction. Our results provide a
convenient starting point to investigate applications of the AdS/CFT
correspondence based on the non-relativistic "stringy" Galilei algebra.Comment: 44 page
The `s-rule' exclusion principle and vacuum interpolation in worldvolume dynamics
We show how the worldvolume realization of the Hanany-Witten effect for a
supersymmetric D5-brane in a D3 background also provides a classical
realization of the `s-rule' exclusion principle. Despite the supersymmetry, the
force on the D5-brane vanishes only in the D5 `ground state', which is shown to
interpolate between 6-dimensional Minkowski space and an -invariant
geometry. The M-theory analogue of these results is briefly
discussed.Comment: 25 pages, 9 figures, LaTeX JHEP styl
M2-Branes and Background Fields
We discuss the coupling of multiple M2-branes to the background 3-form and
6-form gauge fields of eleven-dimensional supergravity, including the coupling
of the Fermions. In particular we show in detail how a natural generalization
of the Myers flux-terms, along with the resulting curvature of the background
metric, leads to mass terms in the effective field theory.Comment: 19 page
The effects of female labor force participation on obesity
This paper assesses whether a causal relationship exists between recent increases in female labor force participation and the increased prevalence of obesity amongst women. The expansions of the Earned Income Tax Credit (EITC) in the 1980s and 1990s have been established by prior literature as having generated variation in female labor supply, particularly amongst single mothers. Here, we use this plausibly exogenous variation in female labor supply to identify the effect of labor force participation on obesity status. We use data from the National Health Interview Survey (NHIS) and replicate labor supply effects of the EITC expansions found in previous literature. This validates employing a difference-in-differences estimation strategy in the NHIS data, as has been done in several other data sets. Depending on the specification, we find that increased labor force participation can account for at most 19% of the observed change in obesity prevalence over our sample period. Our preferred specification, however, suggests that there is no causal link between increased female labor force participation and increased obesity.Women - Employment ; Obesity ; Tax credits
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