124187143
On the approach to the critical point
The mass perturbation yields a new construction for Even + Linear quantum field models. For rp4 models, the Schwinger functions are differentiable in the parameter 6 = 5y~, in the single phase region, and are continuous ac. For the Isingd model, d >_ 2 classical bounds on the critical exponents, e. g. 1 y 2v, are a consequence of an Ornstein-Zernike type upper bound on the two point function.
116890750
Constructive field theory
115879784
Functional Integral Methods in Quantum Field Theory
We give a special form of the Osterwalder-Schrader axioms in terms of conditions on a functional integral S{f} = ∫eiϕ(f)dμ. This yields a simple, self-contained construction of a Hamiltonian H, a relativistic, local boson quantum field Φ, and a Feynman-Kac formula to study perturbations H + Φ of H.
121389988
Whither Axiomatic Field Theory
125224687
Existence of Phase Transitions for phi**4 in Two-Dimensions Quantum Fields
119588441
Response to comments on ``Theoretical Mathematics''
The authors discuss various objections and rejoinders in the collected responses [math.HO/9404229,math.HO/9404236] to their original article on the relationship between mathematics and theoretical physics [math.HO/9307227].
15347782
Planck 2013 results. XXV. Searches for cosmic strings and other topological defects
Planck data have been used to provide stringent new constraints on cosmic strings and other defects. We describe forecasts of the CMB power spectrum induced by cosmic strings, calculating these from network models and simulations using line-of-sight Boltzmann solvers. We have studied Nambu-Goto cosmic strings, as well as field theory strings for which radiative effects are important, thus spanning the range of theoretical uncertainty in the underlying strings models. We have added the angular power spectrum from strings to that for a simple adiabatic model, with the extra fraction defined as f(10) at multipole l = 10. This parameter has been added to the standard six parameter fit using CO S M OM C with flat priors. For the Nambu-Goto string model, we have obtained a constraint on the string tension of G mu/c(2) < 1.5 x 10(-7) and f(10) < 0.015 at 95% confidence that can be improved to G mu/c(2) < 1.3 x 10(-7) and f(10) < 0.010 on inclusion of high-l CMB data. For the Abelian-Higgs field theory model we find, G mu(AH)/c2 < 3.2x10(-7) and f(10) < 0.028. The marginalised likelihoods for f(10) and in the f(10)-Omega(b)h(2) plane are also presented. We have additionally obtained comparable constraints on f(10) for models with semilocal strings and global textures. In terms of the effective defect energy scale these are somewhat weaker at G mu/c(2) < 1.1 x 10(-6). We have made complementarity searches for the specific non-Gaussian signatures of cosmic strings, calibrating with all-sky Planck resolution CMB maps generated from networks of post-recombination strings. We have validated our non-Gaussian searches using these simulated maps in a Planck-realistic context, estimating sensitivities of up to Delta G mu/c(2) approximate to 4 x 10(-7). We have obtained upper limits on the string tension at 95% confidence of G mu/c(2) < 9.0 x 10(-7) with modal bispectrum estimation and G mu/c(2) < 7.8 x 10(-7) for real space searches with Minkowski functionals. These are conservative upper bounds because only post-recombination string contributions have been included in the non-Gaussian analysis.
17110147
A measurement by BOOMERANG of multiple peaks in the angular power spectrum of the cosmic microwave background
This paper presents a measurement of the angular power spectrum of the cosmic microwave background from l = 75 to l = 1025 (~10' to 24) from a combined analysis of four 150 GHz channels in the BOOMERANG experiment. The spectrum contains multiple peaks and minima, as predicted by standard adiabatic inflationary models in which the primordial plasma undergoes acoustic oscillations. These results, in concert with other types of cosmological measurements and theoretical models, significantly constrain the values of ?tot, ?bh2, ?ch2, and ns.
119068104
A Bayesian analysis of the 27 highest energy cosmic rays detected by the Pierre Auger Observatory
It is possible that ultrahigh energy cosmic rays (UHECRs) are generated by active galactic nuclei (AGNs), but there is currently no conclusive evidence for this hypothesis. Several reports of correlations between the arrival directions of UHECRs and the positions of nearby AGNs have been made, the strongest detection coming from a sample of 27 UHECRs detected by the Pierre Auger Observatory (PAO). However, the PAO results were based on a statistical methodology that not only ignored some relevant information (most obviously the UHECR arrival energies, but also some of the information in the arrival directions), but also involved some problematic fine-tuning of the correlation parameters. Here we present a fully Bayesian analysis of the PAO data (collected before 2007 September), which makes use of more of the available information, and find that a fraction FAGN= 0.15+0.10−0.07 of the UHECRs originate from known AGNs in the Veron-Cetty and Veron (VCV) catalogue. The hypothesis that all the UHECRs come from VCV AGNs is ruled out, although there remains a small possibility that the PAO–AGN correlation is coincidental (FAGN= 0.15 is 200 times as probable as FAGN= 0.00).
15450342
THE ANGULAR THREE-POINT CORRELATION FUNCTION IN THE QUASI-LINEAR REGIME
We calculate the normalized angular three-point correlation function (3PCF), q, as well as the normalized angular skewness, s{sub 3}, assuming the small-angle approximation, for a biased mass distribution in flat and open cold dark matter (CDM) models with Gaussian initial conditions. The leading-order perturbative results incorporate the explicit dependence on the cosmological parameters, the shape of the CDM transfer function, the linear evolution of the power spectrum, the form of the assumed redshift distribution function, and linear and nonlinear biasing, which may be evolving. Results are presented for different redshift distributions, including that appropriate for the APM Galaxy Survey, as well as for a survey with a mean redshift of z{approx_equal}1 (such as the VLA FIRST Survey). Qualitatively, many of the results found for s{sub 3} and q are similar to those obtained in a related treatment of the spatial skewness and 3PCF, such as a leading-order correction to the standard result for s{sub 3} in the case of nonlinear bias (as defined for unsmoothed density fields), and the sensitivity of the configuration dependence of q to both cosmological and biasing models. We show that since angular correlation functions (CFs) are sensitive to clustering over a range of redshifts, themore » various evolutionary dependences included in our predictions imply that measurements of q in a deep survey might better discriminate between models with different histories, such as evolving versus nonevolving bias, that can have similar spatial CFs at low redshift. Our calculations employ a derived equation, valid for open, closed, and flat models, to obtain the angular bispectrum from the spatial bispectrum in the small-angle approximation. (c) (c) 2000. The American Astronomical Society.« less
119779449
Planck intermediate results. XV. A study of anomalous microwave emission in Galactic clouds
Anomalous microwave emission (AME) is believed to be due to electric dipole radiation from small spinning dust grains. T he aim of this paper is a statistical study of the basic properties of AME regions and the environment in which they emit. We used WMAP and Planck maps, combined with ancillary radio and IR data, to construct a sample of 98 candidate AME sources, assembling SEDs for each source using aperture photometry on 1 ◦ -smoothed maps from 0.408 GHz up to 3000 GHz. Each spectrum isfitted with a simple model of free-free, synchrotron (where n ecessary), cosmic microwave background (CMB), thermal dust, and spinning dust components. We find that 42 of the 98 sources have sign ificant ( > 5�) excess emission at frequencies between 20 and 60 GHz. An analysis of the potential contribution of optically thick free- free emission from ultracompact Hii regions, using IR colour criteria, reduces the significant A ME sample to 27 regions. The spectrum of the AME is consistent with model spectra of spinning dust. Peak frequencies are in the range 20‐35 GHz except for the California Nebula (NGC1499), which appears to have a high spinning dust peak frequency of (50± 17) GHz. The AME regions tend to be more spatially extended than regions with little or no AME. The AME intensity is strongly correlated with the sub-millimetre/IR flux densities and comparable to previous AME detections i n the literature. AME emissivity, defined as the ratio of AME to dust optical dep th, varies by an order of magnitude for the AME regions. The AME regions tend to be associated with cooler dust in the range 14‐20 K and an average emissivity index, �d, of +1.8, while the non-AME regions are typically warmer, at 20‐27 K. In agreement with previous studies, the AME emissivity appears to decrease with increasing column density. This supports the idea of AME originating from small grains that are known to be depleted in dense regions, probably due to coagulation onto larger grains. We also find a correlation between the AME emissivity (and to a le sser degree the spinning dust peak frequency) and the intensity of the interstellar radiation field, G0. Modelling of this trend suggests that both radiative and collisional excitation are important for the spinning dust em ission. The most significant AME regions tend to have relatively less ion ized gas (free-free emission), although this could be a sele ction effect. The infrared excess, a measure of the heating of dust associated with Hii regions, is typically > 4 for AME sources, indicating that the dust is not primarily heated by hot OB stars. The AME regions are associated with known dark nebulae and have higher 12µm/25µm ratios. The emerging picture is that the bulk of the AME is coming from the polycyclic aromatic hydrocarbons and small dust grains from the colder neutral interstellar medium phase.