Dissociation energy and long-range potential of diatomic molecules from vibrational spacings - The halogens

Dissociation energy and long-range potential of diatomic molecules from vibrational spacings, halogen

Shape resonances and rotationally predissociating levels - The atomic collision time delay functions and quasibound level properties of H2 /Chi /1 Sigma g plus//

Atomic collision time delay functions and quasibound level properties of ground state of molecular hydroge

Unbounded-error quantum computation with small space bounds

We prove the following facts about the language recognition power of quantum Turing machines (QTMs) in the unbounded error setting: QTMs are strictly more powerful than probabilistic Turing machines for any common space bound $s$ satisfying $s(n)=o(\log \log n)$. For "one-way" Turing machines, where the input tape head is not allowed to move left, the above result holds for $s(n)=o(\log n)$. We also give a characterization for the class of languages recognized with unbounded error by real-time quantum finite automata (QFAs) with restricted measurements. It turns out that these automata are equal in power to their probabilistic counterparts, and this fact does not change when the QFA model is augmented to allow general measurements and mixed states. Unlike the case with classical finite automata, when the QFA tape head is allowed to remain stationary in some steps, more languages become recognizable. We define and use a QTM model that generalizes the other variants introduced earlier in the study of quantum space complexity.Comment: A preliminary version of this paper appeared in the Proceedings of the Fourth International Computer Science Symposium in Russia, pages 356--367, 200

The Canada-France deep fields survey-I: 100,000 galaxies, 1 deg^2: a precise measurement of \omega(\theta) to IAB~25

(abridged) Using the UH8K mosaic camera, we have measured the angular correlation function \omega(\theta) for 100,000 galaxies over four widely separated fields totalling ~1\deg^2 and reaching IAB~25.5. With this sample we investigate the dependence of \omega(\theta) at 1', A_\omega(1'), on sample median IAB magnitude in the range 19.5<I(AB-med)<24. Our results show that A_\omega(1') decreases monotonically to IAB~25. At bright magnitudes, \omega(\theta) is consistent with a power-law of slope \delta = -0.8 for 0.2'<\theta<3.0' but at fainter magnitudes we find \delta ~ -0.6. At the 3\sigma level, our observations are still consistent with \delta=-0.8. Furthermore, in the magnitude ranges 18.5<IAB<24.0 and 18.5<IAB<23.0 we find galaxies with 2.6<(V-I)AB<2.9 have A_\omega(1')'s which are ~10x higher than field values. We demonstrate that our model redshift distributions for the faint galaxy population are in good agreement with current spectroscopic observations. Using these predictions, we find that for low-omega cosmologies and assuming r_0=4.3/h Mpc, in the range 19.5<I(AB-med)<22, the growth of galaxy clustering is \epsilon~0. However, at 22<I(AB-med)<24.0, our observations are consistent with \epsilon>1. Models with \epsilon~0 cannot simultaneously match both bright and faint measurements of A_\omega(1`). We show how this result is a natural consequence of the ``bias-free'' nature of the \epsilon formalism and is consistent with the field galaxy population in the range 22.0<IAB<24.0 being dominated by galaxies of low intrinsic luminosity.Comment: 20 pages, 21 figures, requires natbib.sty, accepted for publication in Astronomy and Astrophysic

Equivariant characteristic classes of singular complex algebraic varieties

Homology Hirzebruch characteristic classes for singular varieties have been recently defined by Brasselet-Schuermann-Yokura as an attempt to unify previously known characteristic class theories for singular spaces (e.g., MacPherson-Chern classes, Baum-Fulton-MacPherson Todd classes, and Goresky-MacPherson L-classes, respectively). In this note we define equivariant analogues of these classes for singular quasi-projective varieties acted upon by a finite group of algebraic automorphisms, and show how these can be used to calculate the homology Hirzebruch classes of global quotient varieties. We also compute the new classes in the context of monodromy problems, e.g., for varieties that fiber equivariantly (in the complex topology) over a connected algebraic manifold. As another application, we discuss Atiyah-Meyer type formulae for twisted Hirzebruch classes of global orbifolds.Comment: v2: updates include a motivic approach, as well as an Atiyah-Meyer formula for global orbifolds, including a defect formul

On the hadronic contribution to sterile neutrino production

Sterile neutrinos with masses in the keV range are considered to be a viable candidate for warm dark matter. The rate of their production through active-sterile neutrino transitions peaks, however, at temperatures of the order of the QCD scale, which makes it difficult to estimate their relic abundance quantitatively, even if the mass of the sterile neutrino and its mixing angle were known. We derive here a relation, valid to all orders in the strong coupling constant, which expresses the production rate in terms of the spectral function associated with active neutrinos. The latter can in turn be expressed as a certain convolution of the spectral functions related to various mesonic current-current correlation functions, which are being actively studied in other physics contexts. In the naive weak coupling limit, the appropriate Boltzmann equations can be derived from our general formulae.Comment: 28 pages. v2: small clarifications added, published versio

Real-Time Control of Microgrids with Explicit Power Setpoints: an API for Resource Agents

Renewable energy resources, such as photovoltaic panels, typically have very volatile power-injection characteristics, which poses a number of challenges to the real-time control of electrical grids that contain a significant fraction of these resources. Recently, a new paradigm for controlling such grids, termed COMMELEC, was proposed; it uses explicit power setpoints instead of droop-control. Central to this new paradigm is an abstract message format that enables resources to delegate the decisions related to their control actions to a grid controller. This is essential to the feasibility of the approach, as it makes the grid controller device-independent. However, it leaves to the resource agents the burden of translating device-specific information into this abstract format. In this paper, we present a solution to this problem; more specifically, we present a very simple Application Programming Interface (API) that can be used to design a COMMELEC-compliant resource agent. We present an easy-to-use High-Level API, which supports a pre- defined set of resources, such as a battery or a photovoltaic panel. We also describe a Low-Level API that provides full access to the underlying message format, and allows to design a resource agent that is not supported by the High-Level API. For message serialization, we use the Cap’n Proto framework, which allows for efficient manipulations of the mathematical objects used in COMMELEC