46,481 research outputs found
Quadrature domains and kernel function zipping
It is proved that quadrature domains are ubiquitous in a very strong sense in
the realm of smoothly bounded multiply connected domains in the plane. In fact,
they are so dense that one might as well assume that any given smooth domain
one is dealing with is a quadrature domain, and this allows access to a host of
strong conditions on the classical kernel functions associated to the domain.
Following this string of ideas leads to the discovery that the Bergman kernel
can be zipped down to a strikingly small data set. It is also proved that the
kernel functions associated to a quadrature domain must be algebraic.Comment: 13 pages, to appear in Arkiv for matemati
More Evidence for an Oscillation Superimposed on the Hubble Flow
In a recent investigation evidence was presented for a low-level sinusoidal
oscillation superimposed on top of the Hubble flow. This oscillation was in
V, in a sample of type Ia Supernovae sources with accurate distances,
and it was found to have a wavelength close to 40 Mpc. It became easily visible
after the removal of several previously identified discrete velocity
components. Its amplitude like that of the Hubble velocity showed an increase
with distance, as would be expected for a constant-amplitude space oscillation.
Here we report that this oscillation is also present in distance clumping in
these sources, with the same wavelength, but in phase quadrature. The discrete
velocity components do not play a role in detecting the distance clumping
wavelength. Assuming that time proceeds from high cosmological redshift to low,
the blue-shifted velocity peaks, which represent the contraction stage of the
velocity oscillation, then lead the density peaks. With the discrete velocity
components removed we also find evidence for at least one other, weaker
velocity oscillation. It is found to have a wavelength similar to one reported
in density clumping by previous investigators. In those cases the source
samples were much larger.Comment: 7 pages, with 6 figures, accepted for publication in Astrophysics and
Space Scienc
On The Depolarization Asymmetry Seen in Giant Radio Lobes
The depolarization asymmetry seen in double-lobed radio sources, referred to
as the Laing-Garrington (L-G) effect where more rapid depolarization is seen in
the lobe with no visible jet as the wavelength increases, can be explained
either by internal differences between the two lobes, or by an external Faraday
screen that lies in front of only the depolarized lobe. If the jet
one-sidedness is due to relativistic beaming the depolarization asymmetry must
be due to an intervening Faraday screen. If it is intrinsic the depolarization
asymmetry must be related to internal differences in the lobes. We assume in
this paper that the speed in the outer jet of several Fanaroff-Riley Class 1
(FRI) sources exhibiting the L-G effect is close to the 0.1c reported by
several other investigators. For these sources we find that the jet
one-sidedness cannot be explained by beaming and therefore must be intrinsic.
In these FRI sources the L-G effect must be due to differences that originate
inside the lobes themselves. Although it is not known if the flow in the outer
jets of FRII sources also slows to this speed it is suggested that the
explanation of the L-G effect is likely to be the same in both types. This
argument is strengthened by the recent evidence that FRII galaxies have very
large viewing angles, which in turn implies that the L-G model cannot work
regardless of the jet velocity. It may therefore be too soon to completely rule
out internal depolarization in the lobes as the true explanation for the L-G
effect.Comment: 8 pages with 4 figures. Accepted for publication in Ap&S
WZW action in odd dimensional gauge theories
It is shown that Wess-Zumino-Witten (WZW) type actions can be constructed in
odd dimensional space-times using Wilson line or Wilson loop. WZW action
constructed using Wilson line gives anomalous gauge variations and the WZW
action constructed using Wilson loop gives anomalous chiral transformation. We
show that pure gauge theory including Yang-Mills action, Chern-Simons action
and the WZW action can be defined in odd dimensional space-times with even
dimensional boundaries. Examples in 3D and 5D are given. We emphasize that this
offers a way to generalize gauge theory in odd dimensions. The WZW action
constructed using Wilson line can not be considered as action localized on
boundary space-times since it can give anomalous gauge transformations on
separated boundaries. We try to show that such WZW action can be obtained in
the effective theory when making localized chiral fermions decouple.Comment: 19 pages, text shortened, reference added. Version to appear in PR
The Relativistically Spinning Charged Sphere
When the equatorial spin velocity, , of a charged conducting sphere
approaches , the Lorentz force causes a remarkable rearrangement of the
total charge .
Charge of that sign is confined to a narrow equatorial belt at latitudes while charge of the opposite sign
occupies most of the sphere's surface. The change in field structure is shown
to be a growing contribution of the `magic' electromagnetic field of the
charged Kerr-Newman black hole with Newton's G set to zero. The total charge
within the narrow equatorial belt grows as and tends to
infinity as approaches . The electromagnetic field, Poynting vector,
field angular momentum and field energy are calculated for these
configurations.
Gyromagnetic ratio, g-factor and electromagnetic mass are illustrated in
terms of a 19th Century electron model. Classical models with no spin had the
small classical electron radius a hundredth of the Compton
wavelength, but models with spin take that larger size but are so
relativistically concentrated to the equator that most of their mass is
electromagnetic.
The method of images at inverse points of the sphere is shown to extend to
charges at points with imaginary co-ordinates.Comment: 15 pages, 1figur
An improved Riemann Mapping Theorem and complexity in potential theory
We discuss applications of an improvement on the Riemann mapping theorem
which replaces the unit disc by another "double quadrature domain," i.e., a
domain that is a quadrature domain with respect to both area and boundary arc
length measure. Unlike the classic Riemann Mapping Theorem, the improved
theorem allows the original domain to be finitely connected, and if the
original domain has nice boundary, the biholomorphic map can be taken to be
close to the identity, and consequently, the double quadrature domain close to
the original domain. We explore some of the parallels between this new theorem
and the classic theorem, and some of the similarities between the unit disc and
the double quadrature domains that arise here. The new results shed light on
the complexity of many of the objects of potential theory in multiply connected
domains.Comment: 23 page
Causality and Cirel'son bounds
An EPR-Bell type experiment carried out on an entangled quantum system can
produce correlations stronger than allowed by local realistic theories. However
there are correlations that are no-signaling and are more non local than the
quantum correlations. Here we show that any correlations more non local than
those achievable in an EPR-Bell type experiment necessarily allow -in the
context of the quantum formalism- both for signaling and for generation of
entanglement. We use our approach to rederive Cirel'son bound for the CHSH
expression, and we derive a new Cirel'son type bound for qutrits. We discuss in
detail the interpretation of our approach.Comment: 5 page
How much larger quantum correlations are than classical ones
Considering as distance between two two-party correlations the minimum number
of half local results one party must toggle in order to turn one correlation
into the other, we show that the volume of the set of physically obtainable
correlations in the Einstein-Podolsky-Rosen-Bell scenario is (3 pi/8)^2 = 1.388
larger than the volume of the set of correlations obtainable in local
deterministic or probabilistic hidden-variable theories, but is only 3 pi^2/32
= 0.925 of the volume allowed by arbitrary causal (i.e., no-signaling)
theories.Comment: REVTeX4, 6 page
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