10,047 research outputs found
Deformed Superspace, N=1/2 Supersymmetry and (Non)Renormalization Theorems
We consider a deformed superspace in which the coordinates \theta do not
anticommute, but satisfy a Clifford algebra. We present results on the
properties of N=1/2 supersymmetric theories of chiral superfields in deformed
superspace, taking the Wess-Zumino model as the prototype. We prove new
(non)renormalization theorems: the F-term is radiatively corrected and becomes
indistinguishable from the D-term, while the Fbar-term is not renormalized.
Supersymmetric vacua are critical points of the antiholomorphic superpotential.
The vacuum energy is zero to all orders in perturbation theory. We illustrate
these results with several examples.Comment: 21 pages, 5 figures and one table; V2: references adde
Model building in AdS/CMT: DC conductivity and Hall angle
Using the bottom-up approach in a holographic setting, we attempt to study
both the transport and thermodynamic properties of a generic system in 3+1
dimensional bulk spacetime. We show the exact 1/T and dependence of the
longitudinal conductivity and Hall angle, as seen experimentally in most
copper-oxide systems, which are believed to be close to quantum critical point.
This particular temperature dependence to conductivities are possible in two
different cases: (1) Background solutions with scale invariant and broken
rotational symmetry, (2) solutions with pseudo-scaling and unbroken rotational
symmetry but only at low density limit. Generically, the study of the transport
properties in a scale invariant background solution, using the probe brane
approach, at high density and at low temperature limit suggests us to consider
only metrics with two exponents. More precisely, the spatial part of the metric
components should not be same i.e., . In doing so, we have
generated the above mentioned behavior to conductivity with a very special
behavior to specific heat which at low temperature goes as: .
However, if we break the scaling symmetry of the background solution by
including a nontrivial dilaton, axion or both and keep the rotational symmetry
then also we can generate such a behavior to conductivity but only in the low
density regime. As far as we are aware, this particular temperature dependence
to both the conductivity and Hall angle is being shown for the first time using
holography.Comment: 1+40 pages; v2: Analysis of pseudo-scaling and rotational invariant
solutions are added; v3: Improved presentation; v4: Typos fixed and closer to
journal versio
Phase transitions, entanglement and quantum noise interferometry in cold atoms
We show that entanglement monotones can characterize the pronounced
enhancement of entanglement at a quantum phase transition if they are sensitive
to long-range high order correlations. These monotones are found to develop a
sharp peak at the critical point and to exhibit universal scaling. We
demonstrate that similar features are shared by noise correlations and verify
that these experimentally accessible quantities indeed encode entanglement
information and probe separability.Comment: 4 pages 4 figure
Supersymetry on the Noncommutative Lattice
Built upon the proposal of Kaplan et.al. [hep-lat/0206109], we construct
noncommutative lattice gauge theory with manifest supersymmetry. We show that
such theory is naturally implementable via orbifold conditions generalizing
those used by Kaplan {\sl et.al.} We present the prescription in detail and
illustrate it for noncommutative gauge theories latticized partially in two
dimensions. We point out a deformation freedom in the defining theory by a
complex-parameter, reminiscent of discrete torsion in string theory. We show
that, in the continuum limit, the supersymmetry is enhanced only at a
particular value of the deformation parameter, determined solely by the size of
the noncommutativity.Comment: JHEP style, 1+22 pages, no figure, v2: two references added, v3:
three more references adde
The Effect of Mood-Context on Visual Recognition and Recall Memory
Although it is widely known that memory is enhanced when encoding and retrieval occur in the same state, the impact of elevated stress/arousal is less understood. This study explores mood-dependent memory's effects on visual recognition and recall of material memorized either in a neutral mood or under higher stress/arousal levels. Participants’ (N = 60) recognition and recall were assessed while they experienced either the same or a mismatched mood at retrieval. The results suggested that both visual recognition and recall memory were higher when participants experienced the same mood at encoding and retrieval compared with those who experienced a mismatch in mood context between encoding and retrieval. These findings offer support for a mood dependency effect on both the recognition and recall of visual information
Better age estimations using UV-optical colours: breaking the age-metallicity degeneracy
We demonstrate that the combination of GALEX UV photometry in the FUV (~1530
angstroms) and NUV (~2310 angstroms) passbands with optical photometry in the
standard U,B,V,R,I filters can efficiently break the age-metallicity
degeneracy. We estimate well-constrained ages, metallicities and their
associated errors for 42 GCs in M31, and show that the full set of
FUV,NUV,U,B,V,R,I photometry produces age estimates that are ~90 percent more
constrained and metallicity estimates that are ~60 percent more constrained
than those produced by using optical filters alone. The quality of the age
constraints is comparable or marginally better than those achieved using a
large number of spectrscopic indices.Comment: Published in MNRAS (2007), 381, L74 (doi:
10.1111/j.1745-3933.2007.00370.x
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