Testing Single-Parameter Classical Standpoint Cosmology

Experimental tests of homogeneous-universe classical standpoint cosmology are proposed after presentation of conceptual considerations that encourage this radical departure from the standard model. Among predictions of the new model are standpoint age equal to Hubble time, energy-density parameter $\Omega_0 = 2 - \sqrt{2} =.586$, and relations between redshift, Hubble-scale distribution of matter and galaxy luminosity and angular diameter. These latter relations coincide with those of the standard model for zero deceleration. With eye to further tests, geodesics of the non-Riemannian standpoint metric are explicitly given. Although a detailed thermodynamic ``youthful-standpoint'' approximation remains to be developed (for particle mean free path small on standpoint scale), standpoint temperature depending only on standpoint age is a natural concept, paralleling energy density and redshift that perpetuates thermal spectrum for cosmic background radiation. Prospects for primordial nucleosynthesis are promising.Comment: 27 pages, latexed, math_macros.tex used, full postscript available from: http://theor1.lbl.gov/www/theorgroup/papers/37162.p

Weak Classical-Gravity Source in Standpoint Cosmology

Guided by a linearized approximation to Einstein theory, an interim prescription for ``weak source of gravity'' - - in ``particle'' energy-momentum distributed along standpoint light cone - - is formulated for (classical) standpoint cosmology.Comment: 11 pages, uses math_macros.tex, late

Phase-locking at low-level of quanta

We discuss phase-locking phenomena at low-level of quanta for parametrically driven nonlinear Kerr resonator (PDNR) in strong quantum regime. Oscillatory mode of PDNR is created in the process of a degenerate down-conversion of photons under interaction with a train of external Gaussian pulses. We calculate the Wigner functions of cavity mode showing two-fold symmetry in phase space and analyse formation of phase-locked states in the regular as well as the quantum chaotic regime.Comment: 6 pages, 4 figure

Regional Indexes of Activity: Combining the Old with the New

This paper proposes a framework to construct indexes of activity which links two strands of the index literature – the traditional business cycle analysis and the latent variable approach. To illustrate the method, we apply the framework to Australian regional data, namely to two resource-rich and two service-based states. The results reveal differences in the evolution and drivers of economic activity across the four states. We also demonstrate the value of the Index in a broader context by using a structural vector autoregression (SVAR) approach to analyse the effects of shocks from the US and from China. This Index-SVAR approach facilitates a richer analysis because the unique feature of the index method proposed here allows impulse responses to be traced back to the components.Regional economic activity, coincident indicators, dynamic latent factor model

High-Resolution Spectroscopy during Eclipse of the Young Substellar Eclipsing Binary 2MASS 0535-0546. II. Secondary Spectrum: No Evidence that Spots Cause the Temperature Reversal

We present high-resolution optical spectra of the young brown-dwarf eclipsing binary 2M0535-05, obtained during eclipse of the higher-mass (primary) brown dwarf. Combined with our previous spectrum of the primary alone (Paper I), the new observations yield the spectrum of the secondary alone. We investigate, through a differential analysis of the two binary components, whether cool surface spots are responsible for suppressing the temperature of the primary. In Paper I, we found a significant discrepancy between the empirical surface gravity of the primary and that inferred via fine analysis of its spectrum. Here we find precisely the same discrepancy in surface gravity, both qualitatively and quantitatively. While this may again be ascribed to either cool spots or model opacity errors, it implies that cool spots cannot be responsible for preferentially lowering the temperature of the primary: if they were, spot effects on the primary spectrum should be preferentially larger, and they are not. The Teff we infer for the primary and secondary, from the TiO-epsilon bands alone, show the same reversal, in the same ratio, as is empirically observed, bolstering the validity of our analysis. In turn, this implies that if suppression of convection by magnetic fields on the primary is the fundamental cause of the Teff reversal, then it cannot be a local suppression yielding spots mainly on the primary (though both components may be equally spotted), but a global suppression in the interior of the primary. We briefly discuss current theories of how this might work.Comment: Final ApJ version. Small textual change in summary at the end (Sec 6.2), to include work published after submission of this paper; no changes in our results or conclusion

Exploring the S-Matrix of Massless Particles

We use the recently proposed generalised on-shell representation for scattering amplitudes and a consistency test to explore the space of tree-level consistent couplings in four-dimensional Minkowski spacetime. The extension of the constructible notion implied by the generalised on-shell representation, i.e. the possibility to reconstruct at tree level all the scattering amplitudes from the three-particle ones, together with the imposition of the consistency conditions at four-particle level, allow to rediscover all the known theories and their algebra structure, if any. Interestingly, this analysis seems to leave room for high-spin couplings, provided that at least the requirement of locality is weakened. We do not claim to have found tree-level consistent high-spin theories, but rather that our methods show signatures of them and very likely, with a suitable modification, they can be a good framework to perform a systematic search.Comment: 44 pages, 1 figur

Bistability and chaos at low-level of quanta

We study nonlinear phenomena of bistability and chaos at a level of few quanta. For this purpose we consider a single-mode dissipative oscillator with strong Kerr nonlinearity with respect to dissipation rate driven by a monochromatic force as well as by a train of Gaussian pulses. The quantum effects and decoherence in oscillatory mode are investigated on the framework of the purity of states and the Wigner functions calculated from the master equation. We demonstrate the quantum chaotic regime by means of a comparison between the contour plots of the Wigner functions and the strange attractors on the classical Poincar\'e section. Considering bistability at low-limit of quanta, we analyze what is the minimal level of excitation numbers at which the bistable regime of the system is displayed? We also discuss the formation of oscillatory chaotic regime by varying oscillatory excitation numbers at ranges of few quanta. We demonstrate quantum-interference phenomena that are assisted hysteresis-cycle behavior and quantum chaos for the oscillator driven by the train of Gaussian pulses as well as we establish the border of classical-quantum correspondence for chaotic regimes in the case of strong nonlinearities.Comment: 10 pages, 14 figure

Transition from collisionless to collisional MRI

Recent calculations by Quataert et al. (2002) found that the growth rates of the magnetorotational instability (MRI) in a collisionless plasma can differ significantly from those calculated using MHD. This can be important in hot accretion flows around compact objects. In this paper we study the transition from the collisionless kinetic regime to the collisional MHD regime, mapping out the dependence of the MRI growth rate on collisionality. A kinetic closure scheme for a magnetized plasma is used that includes the effect of collisions via a BGK operator. The transition to MHD occurs as the mean free path becomes short compared to the parallel wavelength 2\pi/k_{\Par}. In the weak magnetic field regime where the Alfv\'en and MRI frequencies $\omega$ are small compared to the sound wave frequency k_{\Par} c_0, the dynamics are still effectively collisionless even if $\omega \ll \nu$, so long as the collision frequency \nu \ll k_{\Par} c_{0}; for an accretion flow this requires \nu \lsim \Omega \sqrt{\beta}. The low collisionality regime not only modifies the MRI growth rate, but also introduces collisionless Landau or Barnes damping of long wavelength modes, which may be important for the nonlinear saturation of the MRI.Comment: 20 pages, 4 figures, submitted to ApJ with a clearer derivation of anisotropic pressure closure from drift kinetic equatio