Dynamical Equations from a First-Order Perturbative Superspace Formulation of 10D N=1 String-Corrected Supergravity (I)

Utilizing a first-order perturbative superspace approach, we derive the bosonic equations of motion for the 10D, N = 1 supergravity fields. We give the Lagrangian corresponding to these equations derived from superspace geometry. Moreover, the equivalence of this Lagrangian to the first-order perturbative component level Lagrangian of anomaly-free supergravity is proven. Our treatment covers both the two-form and six-form formulations.Comment: 20 pages, no figures, references and note in proof adde

D=2 N=(2,2) Semi Chiral Vector Multiplet

We describe a new 1+1 dimensional N=(2,2) vector multiplet that naturally couples to semi chiral superfields in the sense that the gauged supercovariant derivative algebra is only consistent with imposing covariantly semi chiral superfield constraints. It has the advantages that its prepotentials shift by semi chiral superfields under gauge transformations. We also see that the multiplet relates the chiral vector multiplet with the twisted chiral vector multiplet by reducing to either multiplet under appropriate limits without being reducible in terms of the chiral and twisted chiral vector multiplet. This is explained from the superspace geometrical point of view as the result of possessing a symmetry under the discrete supercoordinate transformation that is responsible for mirror copies of supermultiplets. We then describe how to gauge a non linear sigma model with semi chiral superfields using the prepotentials of the new multiplet.Comment: 15 page

Applications of Superspace Techniques to Effective Actions, Complex Geometry, and T Duality in String Theory

We describe the use of superspace techniques to discuss some of the issues in string theory. First we use superspace techniques to derive the effective action for the 10D N=1 Heterotic string perturbatively to first order in the parameter alpha prime. Next we demonstrate how to use the superspace description of the supersymmetric gauge multiplet for chiral superfield in 2d N=(2,2) to discuss T duality for sigma models that realizes a particular case of generalized Kahler geometry. We find that the salient features of T duality are captured but at the cost of introducing unwanted fields in dual sigma model. Fortunately the extra fields decouple from the relevant fields under consideration. This leads us to introduce a new supersymmetric gauge multiplet that will eliminate the need to introduce extra fields in the dual sigma model

T-duality, quotients and generalized Kahler geometry

In this paper we reopen the discussion of gauging the two-dimensional off-shell (2,2) supersymmetric sigma models written in terms of semichiral superfields. The associated target space geometry of this particular sigma model is generalized Kahler (or bi-hermitean with two non-commuting complex structures). The gauging of the isometries of the sigma model is now done by coupling the semichiral superfields to the new (2,2) semichiral vector multiplet. We show that the two moment maps together with a third function form the complete set of three Killing potentials which are associated with this gauging. We show that the Killing potentials lead to the generalized moment maps defined in the context of twisted generalized Kahler geometry. Next we address the question of the T-duality map, while keeping the (2,2) supersymmetry manifest. Using the new vector superfield in constructing the duality functional, under T-duality we swap a pair of left and right semichiral superfields by a pair of chiral and twisted chiral multiplets. We end with a discussion on quotient construction.Comment: 18 page

Gauged (2,2) Sigma Models and Generalized Kahler Geometry

We gauge the (2,2) supersymmetric non-linear sigma model whose target space has bihermitian structure (g, B, J_{\pm}) with noncommuting complex structures. The bihermitian geometry is realized by a sigma model which is written in terms of (2,2) semi-chiral superfields. We discuss the moment map, from the perspective of the gauged sigma model action and from the integrability condition for a Hamiltonian vector field. We show that for a concrete example, the SU(2) x U(1) WZNW model, as well as for the sigma models with almost product structure, the moment map can be used together with the corresponding Killing vector to form an element of T+T* which lies in the eigenbundle of the generalized almost complex structure. Lastly, we discuss T-duality at the level of a (2,2) sigma model involving semi-chiral superfields and present an explicit example.Comment: 33 page

Compact Micromachined Bandpass Filters for Infrared Planetary Spectroscopy

The thermal instrument strawman payload of the Jupiter Europa Orbiter on the Europa Jupiter Science Mission will map out thermal anomalies, the structure, and atmospheric conditions of Europa and Jupiter within the 7-100 micron spectral range. One key requirement for the payload is that the mass cannot exceed 3.7 kg. Consequently, a new generation of light-weight miniaturized spectrometers needs to be developed. On the path toward developing these spectrometers is development of ancillary miniaturized spectroscopic components. In this paper, we present a strategy for making radiation hard and low mass FIR band pass metal mesh filters. Our strategy involves using MEMS-based fabrication techniques, which will permit the quasi-optical filter structures to be made with micron-scale precision. This will enable us to achieve tight control over both the pass band of the filter and the micromachined silicon support structure architecture, which will facilitate integration of the filters for a variety of applications

Radiation Hard Bandpass Filters for Mid- to Far-IR Planetary Instruments

We present a novel method to fabricate compact metal mesh bandpass filters for use in mid- to far-infrared planetary instruments operating in the 20-600 micron wavelength spectral regime. Our target applications include thermal mapping instruments on ESA's JUICE as well as on a de-scoped JEO. These filters are novel because they are compact, customizable, free-standing copper mesh resonant bandpass filters with micromachined silicon support frames. The filters are well suited for thermal mapping mission to the outer planets and their moons because the filter material is radiation hard. Furthermore, the silicon support frame allows for effective hybridization with sensors made on silicon substrates. Using a Fourier Transform Spectrometer, we have demonstrated high transmittance within the passband as well as good out-of-band rejection [1]. In addition, we have developed a unique method of filter stacking in order to increase the bandwidth and sharpen the roll-off of the filters. This method allows one to reliably control the spacing between filters to within 2 microns. Furthermore, our method allows for reliable control over the relative position and orienta-tion between the shared faces of the filters

Compact Micromachined Infrared Bandpass Filters for Planetary Spectroscopy

The future needs of space based observational planetary and astronomy missions include low mass and small volume radiometric instruments that can operate in high radiation and low temperature environments. Here we focus on a central spectroscopic component, the bandpass filter. We model the bandpass response of the filters to target the wavelength of the resonance peaks at 20, 40, and 60 micrometers and report good agreement between the modeled and measured response. We present a technique of using common micromachining processes for semiconductor fabrication to make compact, free standing resonant metal mesh filter arrays with silicon support frames. The process can accommodate multiple detector array architectures and the silicon frame provides lightweight mechanical support with low form factor. We also present a conceptual hybridization of the filters with a detector array

M-theory on Spin(7) Manifolds, Fluxes and 3D, N=1 Supergravity

We calculate the most general causal N=1 three-dimensional, gauge invariant action coupled to matter in superspace and derive its component form using Ectoplasmic integration theory. One example of such an action can be obtained by compactifying M-theory on a Spin(7) holonomy manifold taking non-vanishing fluxes into account. We show that the resulting three-dimensional theory is in agreement with the more general construction. The scalar potential resulting from Kaluza-Klein compactification stabilizes all the moduli fields describing deformations of the metric except for the radial modulus. This potential can be written in terms of the superpotential previously discussed in the literature.Comment: 37 pages no figures (LaTeX 2e