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 $T^2$ 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., $g_{xx}\neq g_{yy}$. 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: $C_V\sim T^3$. 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