3,152 research outputs found
Front Form Spinors in Weinberg-Soper Formalism and Melosh Transformations for any Spin
Using the Weinberg-Soper formalism we construct the front form
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
Space-Time Symmetries: P and CP Violation
We begin with a few remarks on an explicit construction of a
Bargmann-Wightman-Wigner-type quantum field theory [Phys. Lett. B {\bf 316},
102 (1993)] in which bosons and associated antibosons have opposite relative
intrinsic parities. We then construct Majorana ( self
conjugate) and Majorana-like ( self conjugate, chirality
operator) fields. We point out that this new structure in the space time
symmetries may be relevant to and violation.Comment: Talk presened by D. V. Ahluwalia at the III International Wigner
Symposium, Christ Church, Oxford, September 1993
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 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
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
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