Two loop Kahler potential in beta-deformed N=4 SYM theory

In N=2 superconformal field theories the Kahler potential is known to be tree level exact. The beta-deformation of N=4 SU(N) SYM reduces the amount of supersymmetry to N=1, allowing for non-trivial, superconformal loop corrections to the Kahler potential. We analyse the two-loop corrections on the Coulomb branch for a complex deformation. For an arbitrary chiral field in the Cartan subalgebra we reduce the problem of computing the two-loop Kahler potential to that of diagonalising the mass matrix, we then present the result in a manifestly superconformal form. The mass matrix diagonalisation is performed for the case of the chiral background that induces the breaking pattern SU(N) -> SU(N-2)*U(1)^2. Then, for the gauge group SU(3), the Kahler potential is explicitly computed to the two-loop order.Comment: 24 pages, 1 figure, version published in JHE

The one-loop effective potential of the Wess-Zumino model revisited

The full one-loop supersymmetric effective potential for the Wess-Zumino model is calculated using superfield techniques. This includes the K\"ahler potential and the auxiliary field potential, of which the former was originally computed in 1993 while the latter is derived for the first time. In the purely bosonic sector our results match those of older component field calculations. In light of prior contradictory results found in the literature, the calculation of the leading term in the auxiliary field potential is approached in a variety of ways. Issues related to conditional convergence that occur during these calculations and their possible consequences are discussed.Comment: 32 page

Preliminary evidence of increased striatal dopamine in a nonhuman primate model of maternal immune activation.

Women exposed to a variety of viral and bacterial infections during pregnancy have an increased risk of giving birth to a child with autism, schizophrenia or other neurodevelopmental disorders. Preclinical maternal immune activation (MIA) models are powerful translational tools to investigate mechanisms underlying epidemiological links between infection during pregnancy and offspring neurodevelopmental disorders. Our previous studies documenting the emergence of aberrant behavior in rhesus monkey offspring born to MIA-treated dams extends the rodent MIA model into a species more closely related to humans. Here we present novel neuroimaging data from these animals to further explore the translational potential of the nonhuman primate MIA model. Nine male MIA-treated offspring and 4 controls from our original cohort underwent in vivo positron emission tomography (PET) scanning at approximately 3.5-years of age using [18F] fluoro-l-m-tyrosine (FMT) to measure presynaptic dopamine levels in the striatum, which are consistently elevated in individuals with schizophrenia. Analysis of [18F]FMT signal in the striatum of these nonhuman primates showed that MIA animals had significantly higher [18F]FMT index of influx compared to control animals. In spite of the modest sample size, this group difference reflects a large effect size (Cohen's d = 0.998). Nonhuman primates born to MIA-treated dams exhibited increased striatal dopamine in late adolescence-a hallmark molecular biomarker of schizophrenia. These results validate the MIA model in a species more closely related to humans and open up new avenues for understanding the neurodevelopmental biology of schizophrenia and other neurodevelopmental disorders associated with prenatal immune challenge

Relating the Komargodski-Seiberg and Akulov-Volkov actions: Exact nonlinear field redefinition

This paper constructs an exact field redefinition that maps the Akulov-Volkov action to that recently studied by Komargodski and Seiberg in arXiv:0907.2441. It is also shown that the approach advocated in arXiv:1003.4143v2 and arXiv:1009.2166 for deriving such a relationship is inconsistent.Comment: 8 pages; V2: a reference added, minor changes mad

Facial grimace testing as an assay of neuropathic pain-related behavior in a mouse model of cervical spinal cord injury.

A major portion of individuals affected by traumatic spinal cord injury (SCI) experience one or more types of chronic neuropathic pain (NP), which is often intractable to currently available treatments. The availability of reliable behavioral assays in pre-clinical models of SCI-induced NP is therefore critical to assess the efficacy of new potential therapies. Commonly used assays to evaluate NP-related behavior in rodents, such as Hargreaves thermal and von Frey mechanical testing, rely on the withdrawal response to an evoked stimulus. However, other assays that test spontaneous/non-evoked NP-related behavior or supraspinal aspects of NP would be highly useful for a more comprehensive assessment of NP following SCI. The Mouse Grimace Scale (MGS) is a tool to assess spontaneous, supraspinal pain-like behaviors in mice; however, the assay has not been characterized in a mouse model of SCI-induced chronic NP, despite the critical importance of mouse genetics as an experimental tool. We found that beginning 2 weeks after cervical contusion, SCI mice exhibited increased facial grimace features compared to laminectomy-only control mice, and this grimace phenotype persisted to the chronic time point of 5 weeks post-injury. We also found a significant relationship between facial grimace score and the evoked forepaw withdrawal response in both the Hargreaves and von Frey tests at 5 weeks post-injury when both laminectomy-only and SCI mice were included in the analysis. However, within only the SCI group, there was no correlation between grimace score and Hargreaves or von Frey responses. These results indicate both that facial grimace analysis can be used as an assay of spontaneous NP-related behavior in the mouse model of SCI and that the information provided by the MGS may be different than that provided by evoked tests of sensory function

Supersymmetric Euler-Heisenberg effective action: Two-loop results

The two-loop Euler-Heisenberg-type effective action for N = 1 supersymmetric QED is computed within the background field approach. The background vector multiplet is chosen to obey the constraints D_\a W_\b = D_{(\a} W_{\b)} = const, but is otherwise completely arbitrary. Technically, this calculation proves to be much more laborious as compared with that carried out in hep-th/0308136 for N = 2 supersymmetric QED, due to a lesser amount of supersymmetry. Similarly to Ritus' analysis for spinor and scalar QED, the two-loop renormalisation is carried out using proper-time cut-off regularisation. A closed-form expression is obtained for the holomorphic sector of the two-loop effective action, which is singled out by imposing a relaxed super self-duality condition.Comment: 27 pages, 2 eps figures, LaTeX; V2: typos corrected, comments and reference adde

Link between supercurrent diode and anomalous Josephson effect revealed by gate-controlled interferometry

In Josephson diodes the asymmetry between positive and negative current branch of the current-phase relation leads to a polarity-dependent critical current and Josephson inductance. The supercurrent nonreciprocity can be described as a consequence of the anomalous Josephson effect -- a $\varphi_0$-shift of the current-phase relation -- in multichannel ballistic junctions with strong spin-orbit interaction. In this work, we simultaneously investigate $\varphi_0$-shift and supercurrent diode efficiency on the same Josephson junction by means of a superconducting quantum interferometer. By electrostatic gating, we reveal a direct link between $\varphi_0$-shift and diode effect. Our findings show that the supercurrent diode effect mainly results from magnetochiral anisotropy induced by spin-orbit interaction in combination with a Zeeman field.Comment: 15 pages, 8 figure