4,413 research outputs found
The range of the tangential Cauchy-Riemann system on a CR embedded manifold
We prove that every compact, pseudoconvex, orientable, CR manifold of \C^n,
bounds a complex manifold in the sense. In particular, the
tangential Cauchy-Riemann system has closed range
Renormalization Group Treatment of Nonrenormalizable Interactions
The structure of the UV divergencies in higher dimensional nonrenormalizable
theories is analysed. Based on renormalization operation and renormalization
group theory it is shown that even in this case the leading divergencies
(asymptotics) are governed by the one-loop diagrams the number of which,
however, is infinite. Explicit expression for the one-loop counter term in an
arbitrary D-dimensional quantum field theory without derivatives is suggested.
This allows one to sum up the leading asymptotics which are independent of the
arbitrariness in subtraction of higher order operators. Diagrammatic
calculations in a number of scalar models in higher loops are performed to be
in agreement with the above statements. These results do not support the idea
of the na\"ive power-law running of couplings in nonrenormalizable theories and
fail (with one exception) to reveal any simple closed formula for the leading
terms.Comment: LaTex, 11 page
Non-Relativistic Gravitation: From Newton to Einstein and Back
We present an improvement to the Classical Effective Theory approach to the
non-relativistic or Post-Newtonian approximation of General Relativity. The
"potential metric field" is decomposed through a temporal Kaluza-Klein ansatz
into three NRG-fields: a scalar identified with the Newtonian potential, a
3-vector corresponding to the gravito-magnetic vector potential and a 3-tensor.
The derivation of the Einstein-Infeld-Hoffmann Lagrangian simplifies such that
each term corresponds to a single Feynman diagram providing a clear physical
interpretation. Spin interactions are dominated by the exchange of the
gravito-magnetic field. Leading correction diagrams corresponding to the 3PN
correction to the spin-spin interaction and the 2.5PN correction to the
spin-orbit interaction are presented.Comment: 10 pages, 3 figures. v2: published version. v3: Added a computation
of Einstein-Infeld-Hoffmann in higher dimensions within our improved ClEFT
which partially confirms and partially corrects a previous computation. See
notes added at end of introductio
Matched Asymptotic Expansion for Caged Black Holes - Regularization of the Post-Newtonian Order
The "dialogue of multipoles" matched asymptotic expansion for small black
holes in the presence of compact dimensions is extended to the Post-Newtonian
order for arbitrary dimensions. Divergences are identified and are regularized
through the matching constants, a method valid to all orders and known as
Hadamard's partie finie. It is closely related to "subtraction of
self-interaction" and shows similarities with the regularization of quantum
field theories. The black hole's mass and tension (and the "black hole
Archimedes effect") are obtained explicitly at this order, and a Newtonian
derivation for the leading term in the tension is demonstrated. Implications
for the phase diagram are analyzed, finding agreement with numerical results
and extrapolation shows hints for Sorkin's critical dimension - a dimension
where the transition turns second order.Comment: 28 pages, 5 figures. v2:published versio
A nonlinear scalar model of extreme mass ratio inspirals in effective field theory I. Self force through third order
The motion of a small compact object in a background spacetime is
investigated in the context of a model nonlinear scalar field theory. This
model is constructed to have a perturbative structure analogous to the General
Relativistic description of extreme mass ratio inspirals (EMRIs). We apply the
effective field theory approach to this model and calculate the finite part of
the self force on the small compact object through third order in the ratio of
the size of the compact object to the curvature scale of the background (e.g.,
black hole) spacetime. We use well-known renormalization methods and
demonstrate the consistency of the formalism in rendering the self force finite
at higher orders within a point particle prescription for the small compact
object. This nonlinear scalar model should be useful for studying various
aspects of higher-order self force effects in EMRIs but within a comparatively
simpler context than the full gravitational case. These aspects include
developing practical schemes for higher order self force numerical
computations, quantifying the effects of transient resonances on EMRI waveforms
and accurately modeling the small compact object's motion for precise
determinations of the parameters of detected EMRI sources.Comment: 30 pages, 8 figure
CMB Signals of Neutrino Mass Generation
We propose signals in the cosmic microwave background to probe the type and
spectrum of neutrino masses. In theories that have spontaneous breaking of
approximate lepton flavor symmetries at or below the weak scale, light
pseudo-Goldstone bosons recouple to the cosmic neutrinos after nucleosynthesis
and affect the acoustic oscillations of the electron-photon fluid during the eV
era. Deviations from the Standard Model are predicted for both the total energy
density in radiation during this epoch, \Delta N_nu, and for the multipole of
the n'th CMB peak at large n, \Delta l_n. The latter signal is difficult to
reproduce other than by scattering of the known neutrinos, and is therefore an
ideal test of our class of theories. In many models, the large shift, \Delta
l_n \approx 8 n_S, depends on the number of neutrino species that scatter via
the pseudo-Goldstone boson interaction. This interaction is proportional to the
neutrino masses, so that the signal reflects the neutrino spectrum. The
prediction for \Delta N_nu is highly model dependent, but can be accurately
computed within any given model. It is very sensitive to the number of
pseudo-Goldstone bosons, and therefore to the underlying symmetries of the
leptons, and is typically in the region of 0.03 < \Delta N_nu < 1. This signal
is significantly larger for Majorana neutrinos than for Dirac neutrinos, and,
like the scattering signal, varies as the spectrum of neutrinos is changed from
hierarchical to inverse hierarchical to degenerate.Comment: 40 pages, 4 figure
The k-Point Random Matrix Kernels Obtained from One-Point Supermatrix Models
The k-point correlation functions of the Gaussian Random Matrix Ensembles are
certain determinants of functions which depend on only two arguments. They are
referred to as kernels, since they are the building blocks of all correlations.
We show that the kernels are obtained, for arbitrary level number, directly
from supermatrix models for one-point functions. More precisely, the generating
functions of the one-point functions are equivalent to the kernels. This is
surprising, because it implies that already the one-point generating function
holds essential information about the k-point correlations. This also
establishes a link to the averaged ratios of spectral determinants, i.e. of
characteristic polynomials
Observations of Rapid Disk-Jet Interaction in the Microquasar GRS 1915+105
We present evidence that ~ 30 minute episodes of jet formation in the
Galactic microquasar GRS 1915+105 may sometimes entirely be a superposition of
smaller, faster phenomena. We base this conclusion on simultaneous X-ray and
infrared observations in July 2002, using the Rossi X-ray Timing Explorer and
the Palomar 5 meter telescope. On two nights, we observed quasi-periodic
infrared flares from GRS 1915+105, each accompanied by a set of fast
oscillations in the X-ray light curve (indicating an interaction between the
jet and accretion disk). In contrast to similar observations in 1997, we find
that the duration of each X-ray cycle matches the duration of its accompanying
infrared flare, and we observed one instance in which an isolated X-ray
oscillation occurred at the same time as a faint infrared "subflare" (of
duration ~ 150 seconds) superimposed on one of the main flares. From these
data, we are able to conclude that each X-ray oscillation had an associated
faint infrared flare and that these flares blend together to form, and entirely
comprise, the ~ 30 minute events we observed. Part of the infrared emission in
1997 also appears to be due to superimposed small flares, but it was
overshadowed by infrared-bright ejections associated with the appearance of a
sharp "trigger" spike in each X-ray cycle that were not present in 2002. We
also study the evolution of the X-ray spectrum and find significant differences
in the high energy power law component, which was strongly variable in 1997 but
not in 2002. Taken together, these observations reveal the diversity of ways in
which the accretion disk and jet in black hole systems are capable of
interacting and solidify the importance of the trigger spike for large
ejections to occur on ~ 30 minute timescales in GRS 1915+105.Comment: 17 pages, 9 figures; accepted for publication in The Astrophysical
Journa
Does Low Frequency X-ray QPO Behavior in GRS 1915+105 Influence Subsequent X-ray and Infrared Evolution?
Using observations with the Rossi X-ray Timing Explorer, we examine the
behavior of 2-10 Hz quasi-periodic oscillations (QPOs) during spectrally-hard
dips in the x-ray light curve of GRS 1915+105 that are accompanied by infrared
flares. Of the twelve light-curves examined, nine are beta-class and three are
alpha-class following the scheme of Belloni et al. (2000). In most cases, the
QPO frequency is most strongly correlated to the power law flux, which
partially contradicts some earlier claims that the strongest correlation is
between QPO frequency and blackbody flux. Seven beta-class curves are highly
correlated to blackbody features. In several cases, the QPO evolution appears
to decouple from the spectral evolution. We find that beta-class light-curves
with strong correlations can be distinguished from those without by their
``trigger spike'' morphology. We also show that the origin and strength of the
subsequent infrared flare may be causally linked to the variations in QPO
frequency evolution and not solely tied to the onset of soft x-ray flaring
behavior. We divide the twelve alpha- and beta-class light-curves into three
groups based on the evolution of the QPO, the morphology of the trigger spike,
and the infrared flare strength. An apparent crossover case leads us to
conclude that these groups are not unique modes but represent part of a
continuum of accretion behaviors. We believe the QPO behavior at the initiation
of the hard dip can ultimately be used to determine the terminating x-ray
behavior, and the following infrared flaring behavior.Comment: 29 pages, 9 figures, to be published in Ap
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