Front Form Spinors in Weinberg-Soper Formalism and Melosh Transformations for any Spin

Using the Weinberg-Soper formalism we construct the front form $(j,0)\oplus(0,j)$ spinors. Explicit expressions for the generalised Melosh transformations up to spin two are obtained. The formalism, without explicitly invoking any wave equations, reproduces spin one half front-form results of Melosh, Lepage and Brodsky, and Dziembowski.Comment: 16 Pages, RevTex. We continue to receive reprint requests for this paper. So we now archive it her

On the spin of gravitational bosons

We unearth spacetime structure of massive vector bosons, gravitinos, and gravitons. While the curvatures associated with these particles carry a definite spin, the underlying potentials cannot be, and should not be, interpreted as single spin objects. For instance, we predict that a spin measurement in the rest frame of a massive gravitino will yield the result 3/2 with probability one half, and 1/2 with probability one half. The simplest scenario leaves the Riemannian curvature unaltered; thus avoiding conflicts with classical tests of the theory of general relativity. However, the quantum structure acquires additional contributions to the propagators, and it gives rise to additional phases.Comment: Honorable mention, 2002 Gravity Research Foundation Essay

Domain Size Dependence of Piezoelectric Properties of Ferroelectrics

The domain size dependence of piezoelectric properties of ferroelectrics is investigated using a continuum Ginzburg-Landau model that incorporates the long-range elastic and electrostatic interactions. Microstructures with desired domain sizes are created by quenching from the paraelectric phase by biasing the initial conditions. Three different two-dimensional microstructures with different sizes of the $90^{o}$ domains are simulated. An electric field is applied along the polar as well as non-polar directions and the piezoelectric response is simulated as a function of domain size for both cases. The simulations show that the piezoelectric coefficients are enhanced by reducing the domain size, consistent with recent experimental results of Wada and Tsurumi (Brit. Ceram. Trans. {\bf 103}, 93, 2004) on domain engineered $BaTiO_{3}$Comment: submitted to Physical Review

Neutrino oscillations with disentanglement of a neutrino from its partners

We bring attention to the fact that in order to understand existing data on neutrino oscillations, and to design future experiments, it is imperative to appreciate the role of quantum entanglement. Once this is accounted for, the resulting energy-momentum conserving phenomenology requires a single new parameter related to disentanglement of a neutrino from its partners. This parameter may not be CP symmetric. We illustrate the new ideas, with potentially measurable effects, in the context of a novel experiment recently proposed by Gavrin, Gorbachev, Veretenkin, and Cleveland. The strongest impact of our ideas is on the resolution of various anomalies in neutrino oscillations and on neutrino propagation in astrophysical environments.Comment: 6 page

New symmetry current for massive spin-3/2 fields

We present several new results which will be of value to theorists working with massive spin-3/2 vector-spinor fields as found, for example, in low and intermediate energy hadron physics and also linearized supergravity. The general lagrangian and propagator for a vector-spinor field in d-dimensions is given. It is shown that the observables of the theory are invariant under a novel continuous symmetry group which is also extended to an algebra. A new technique is developed for exploring the consequences of the symmetry and a previously unknown conserved vector current and charge are found. The current leads to new interactions involving spin-3/2 particles and may have important experimental consequences.Comment: 9 pages, references updated and minor change