arXiv subjects

S. Sukkhasena

Publications and source records attributed to S. Sukkhasena.

3 recordsLinked to original sources

arXiv2013

The Graviton Propagator with a Non-Conserved External Generating Source

A novel general expression is obtained for the graviton propagator from Lagrangian field theory by taking into account the necessary fact that in the functional differential approach of quantum field theory, in order to generate non-linearities in gravitation and interactions with matter, the external source $T_{μν}$, coupled to the gravitational field, should \textit{a priori} not be conserved $\partial^μT_{μν}\neq 0$, so variations with respect to its ten components may be varied \textit{independently}. The resulting propagator is the one which arises in the functional approach and does \textit{not} coincide with the corresponding time-ordered product of two fields and it includes so-called Schwinger terms. The quantization is carried out in a gauge corresponding to physical states with two polarization states to ensure positivity in quantum applications.

hep-th↗

arXiv2013

Gravitons, induced geometry and expectation value formalism at finite temperature

After establishing the positivity constraint and spin content of the theory for gravitons interacting with a necessarily, and \textit{a priori}, \textit{non}-conserved external energy-momentum tensor, the expectation value formalism of the theory is developed at \textit{finite} temperature in the functional \textit{differential} treatment of quantum field theory. The necessity of having, \textit{a priori}, a non-conserved external energy-momentum tensor is an obvious technical requirement so that its respective ten components may be varied \textit{independently} in order to generate expectation values and non-linearities in the theory. The covariance of the \textit{induced} Riemann curvature tensor, in the initial vacuum, is established even for the quantization in a gauge corresponding only to two physical states of the gravitons as established above. As an application, the \textit{induced} correction to the metric and the underlying geometry is investigated due to a closed string arising from the Nambu action as a solution of a circularly oscillating string as, perhaps, the simplest generalization of a limiting point-like object. Finally it is discussed on why the geometry of spacetime may, in general, depend on temperature due to radiative corrections and its physical significance is emphasized.

hep-th↗

arXiv2004

Projection of relativistically moving objects on a two-dimensional plane, the `train' paradox and the visibility of the Lorentz contraction

Although many papers have appeared on the theory of photographing relativistically moving objects, pioneered by the classic work of Penrose and Terrell, three problems remain outstanding. (1) There does not seem to exist a general formula which gives the projection of a relativistically moving object, applicable to any object no matter how complicated, on a two-dimensional plane in conformity with Terrell's observation. (2) No resolution seems to have been provided for the associated so-called `train' paradox. (3) No analytical demonstration seems to have been offered on how the Lorentz contraction may be actually detected on a photograph. This paper addresses all of these three problems. The analysis does not require any more than trigonometry and elementary differentiation.

physics.class-ph↗