Dark Energy and the Nature of the Graviton

Does the existence of dark energy suggest that there is more to the graviton than we think we know?Comment: 4 page

Some remarks on neutrino oscillation and masses

We discuss an Ansatz for the neutrino mixing matrix and speculate on the form and origin of the neutrino mass matrix.Comment: Latex 9 pages, Talk presented at the neutrino conference held in Palm Cove, Australia, June 200

Neutrino Anomalies in an Extended Zee Model

We discuss an extended $SU(2)\times U(1)$ model which naturally leads to mass scales and mixing angles relevant for understanding both the solar and atmospheric neutrino anomalies. No right-handed neutrinos are introduced in the model.The model uses a softly broken $L_e-L_{\mu}-L_{\tau}$ symmetry. Neutrino masses arise only at the loop level. The one-loop neutrino masses which arise as in the Zee model solve the atmospheric neutrino anomaly while breaking of $L_e-L_{\mu}-L_{\tau}$ generates at two-loop order a mass splitting needed for the vacuum solution of the solar neutrino problem. A somewhat different model is possible which accommodates the large-angle MSW resolution of the solar neutrino problem.Comment: 11 pages including 2 figures; a reference added and text changed accordingl

Revenue, Efficiency, and Equity Aspects of Major Taxes in Chile: A Preliminary Assessment

This paper assesses selected revenue, efficiency, and equity aspects of Chile’s major taxes, i.e., the income tax, the value-added tax (VAT), and excises. Chile’s present overall tax burden, at about 20 percent of GDP, is in line with that in its neighboring countries. Whether any change from this level is desirable depends in a fundamental way on the public expenditure needs of the country without jeopardizing macroeconomic stability. Chile has a top personal income tax (PIT) rate (45 percent) that is at the high end of the international spectrum, and a corporate income tax (CIT) rate (15 percent) that is an outlier at the low end. The gap between these two rates (the income rate gap) of 30 percentage points could entail important revenue, efficiency, and equity costs that must be weighed carefully against any perceived or actual benefits. It may be worthwhile to undertake an assessment of the revenue and efficiency costs relative to the expected benefits of some aspects of the income tax system. Namely, saving incentives presently available, the cost effectiveness of the global complementary tax in achieving its revenue and equity objectives of taxing income on a global income basis, simpler ways of taxing capital and labor incomes, the introduction of royalties for the exploitation of natural resources. There are also a number of areas where existing policies could be reevaluated to enhance the efficiency and revenue potential of the VAT and excises. They include: (1) the special VAT credit to the construction sector; (2) the present exclusion of the excise revenue on many excisable goods--especially petroleum products--from the VAT base; (3) the role of the stamp duties and the VAT treatment of the financial sector; and (4) the appropriate excise burdens on motor vehicles and petroleum products for revenue and environmental reasons.

Message in the Sky

We argue that the cosmic microwave background (CMB) provides a stupendous opportunity for the Creator of universe our (assuming one exists) to have sent a message to its occupants, using known physics. Our work does not support the Intelligent Design movement in any way whatsoever, but asks, and attempts to answer, the entirely scientific question of what the medium and message might be IF there was actually a message. The medium for the message is unique. We elaborate on this observation, noting that it requires only careful adjustment of the fundamental Lagrangian, but no direct intervention in the subsequent evolution of the universe.Comment: 3 pages, revtex; to appear in Mod.Phys.Lett.

Generalized Supersymmetric Quantum Mechanics and Reflectionless Fermion Bags in 1+1 Dimensions

We study static fermion bags in the 1+1 dimensional Gross-Neveu and Nambu-Jona-Lasinio models. It has been known, from the work of Dashen, Hasslacher and Neveu (DHN), followed by Shei's work, in the 1970's, that the self-consistent static fermion bags in these models are reflectionless. The works of DHN and of Shei were based on inverse scattering theory. Several years ago, we offered an alternative argument to establish the reflectionless nature of these fermion bags, which was based on analysis of the spatial asymptotic behavior of the resolvent of the Dirac operator in the background of a static bag, subjected to the appropriate boundary conditions. We also calculated the masses of fermion bags based on the resolvent and the Gelfand-Dikii identity. Based on arguments taken from a certain generalized one dimensional supersymmetric quantum mechanics, which underlies the spectral theory of these Dirac operators, we now realize that our analysis of the asymptotic behavior of the resolvent was incomplete. We offer here a critique of our asymptotic argument.Comment: 33 pages, 2 figure

A speculative relation between the cosmological constant and the Planck mass

We propose the relation $M_\Lambda \sim (M_{Pl} M_U)^{1/2}$ where $M_\Lambda$, $M_{Pl},$ and $M_U$ denote the mass scale associated with the cosmological constant, the gravitational interaction, and the size of the universe respectively.Comment: 3 page