853 research outputs found
Quantization of the First-Order Two-Dimensional Einstein-Hilbert Action
A canonical analysis of the first-order two-dimensional Einstein-Hilbert
action has shown it to have no physical degrees of freedom and to possess an
unusual gauge symmetry with a symmetric field acting as a gauge
function. Some consequences of this symmetry are explored. The action is
quantized and it is shown that all loop diagrams beyond one-loop order vanish.
Furthermore, explicit calculation of the one-loop two-point function shows that
it too vanishes, with the contribution of the ghost loop cancelling that of the
``graviton'' loop
Gauge Dependence in Chern-Simons Theory
We compute the contribution to the modulus of the one-loop effective action
in pure non-Abelian Chern-Simons theory in an arbitrary covariant gauge. We
find that the results are dependent on both the gauge parameter () and
the metric required in the gauge fixing. A contribution arises that has not
been previously encountered; it is of the form . This is possible as in three dimensions
is dimensionful. A variant of proper time regularization is used to render
these integrals well behaved (although no divergences occur when the
regularization is turned off at the end of the calculation). Since the original
Lagrangian is unaltered in this approach, no symmetries of the classical theory
are explicitly broken and is handled unambiguously
since the system is three dimensional at all stages of the calculation. The
results are shown to be consistent with the so-called Nielsen identities which
predict the explicit gauge parameter dependence using an extension of BRS
symmetry. We demonstrate that this dependence may potentially
contribute to the vacuum expectation values of products of Wilson loops.Comment: 17 pp (including 3 figures). Uses REVTeX 3.0 and epsfig.sty
(available from LANL). Latex thric
The Double Slit Experiment With Polarizers
The double slit experiment provides a standard way of demonstrating how
quantum mechanics works. We consider modifying the standard arrangement so that
a photon beam incident upon the double slit encounters a polarizer in front of
either one or both of the slits.Comment: 6 page
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