1,271 research outputs found
Reduced Hamiltonian for next-to-leading order Spin-Squared Dynamics of General Compact Binaries
Within the post Newtonian framework the fully reduced Hamiltonian (i.e., with
eliminated spin supplementary condition) for the next-to-leading order
spin-squared dynamics of general compact binaries is presented. The Hamiltonian
is applicable to the spin dynamics of all kinds of binaries with
self-gravitating components like black holes and/or neutron stars taking into
account spin-induced quadrupolar deformation effects in second post-Newtonian
order perturbation theory of Einstein's field equations. The corresponding
equations of motion for spin, position and momentum variables are given in
terms of canonical Poisson brackets. Comparison with a nonreduced potential
calculated within the Effective Field Theory approach is made.Comment: 11 pages, minor changes to match published version at CQ
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
Entanglement and nonclassical properties of hypergraph states
Hypergraph states are multi-qubit states that form a subset of the locally
maximally entangleable states and a generalization of the well--established
notion of graph states. Mathematically, they can conveniently be described by a
hypergraph that indicates a possible generation procedure of these states;
alternatively, they can also be phrased in terms of a non-local stabilizer
formalism. In this paper, we explore the entanglement properties and
nonclassical features of hypergraph states. First, we identify the equivalence
classes under local unitary transformations for up to four qubits, as well as
important classes of five- and six-qubit states, and determine various
entanglement properties of these classes. Second, we present general conditions
under which the local unitary equivalence of hypergraph states can simply be
decided by considering a finite set of transformations with a clear
graph-theoretical interpretation. Finally, we consider the question whether
hypergraph states and their correlations can be used to reveal contradictions
with classical hidden variable theories. We demonstrate that various
noncontextuality inequalities and Bell inequalities can be derived for
hypergraph states.Comment: 29 pages, 5 figures, final versio
Anisotropic second-order nonlinearities of organic monolayers.
Monolayers prepared from hemicyanine chromophores of high second-order nonlinearity (β=1.3Ă10â26 esu at resonance) have been used to study anisotropies of the concomitant Ď(2)-susceptibility tensor. All components of this third-rank tensor have been determined by Fourier analysis of the anisotropic coverage density Ns(Ď) with respect to the angle of rotation about surface normal. Depending on the preparation both Cs and C2v symmetry could be identified
Next-to-leading order spin-orbit and spin(a)-spin(b) Hamiltonians for n gravitating spinning compact objects
We derive the post-Newtonian next-to-leading order conservative spin-orbit
and spin(a)-spin(b) gravitational interaction Hamiltonians for arbitrary many
compact objects. The spin-orbit Hamiltonian completes the knowledge of
Hamiltonians up to and including 2.5PN for the general relativistic three-body
problem. The new Hamiltonians include highly nontrivial three-body
interactions, in contrast to the leading order consisting of two-body
interactions only. This may be important for the study of effects like Kozai
resonances in mergers of black holes with binary black holes.Comment: 13 pages, 1 Mathematica source file, v2: submitted version, v3:
published version, some minor correction
Vaccine-preventable haemophilus influenza type B disease burden and cost-effectiveness of infant vaccination in Indonesia.
BACKGROUND: Most of Asia, including Indonesia, does not use Haemophilus influenzae type b (Hib) conjugate vaccines. We estimated total vaccine-preventable disease burden and the cost-effectiveness of Hib conjugate vaccine in Indonesia. METHODS: Hib pneumonia and meningitis incidences for children with access to health care were derived from a randomized vaccine probe study on Lombok Island, Indonesia during 1998-2002. Incidences were adjusted for limited access to care. Health system and patient out-of-pocket treatment cost data were collected concurrent with the probe study. For Hib vaccine in monovalent and combined (with DTP-HepB) presentations, we used 2007 UNICEF vaccine prices of US3.75 per dose. RESULTS: For the 2007 Indonesian birth cohort, Hib vaccine would prevent meningitis in 1 of every 179 children, pneumonia in 1 of every 18 children, and 4.9% of mortality among those younger than 5 years. The total incremental societal costs of introducing Hib vaccine in monovalent and pentavalent presentations were, respectively, US8.93 per child vaccinated. Annual discounted treatment costs averted amounted to 20% of pentavalent vaccine costs. For the pentavalent vaccine, the incremental costs per discounted death and disability adjusted life-year averted amounted to US74, respectively, versus 102 for monovalent vaccine. CONCLUSIONS: Routine infant Hib vaccination would prevent a large burden of pediatric illness and death in Indonesia. Even without external funding support, Hib vaccine will be a highly cost-effective intervention in either a monovalent or pentavalent presentation based on commonly used benchmarks
Maineâs Food System: An Overview and Assessment
From an agrarian and seafaring past, Maineâs food system has seen profound changes over the past two centuries. Grain, milk, livestock, fish, potatoes, vegetables and fruits used to come from small, family farms. Today, most people in Maine donât know where their food comes from. Many are dependent on federal, state and local âemergency food systemsâ such as food stamps, food pantries, and childhood nutrition programs. Food-processing facilities, distribution systems, and value-added products are in short supply. Nevertheless, Maine has a diversity and abundance of food prodÂucts. In this article, the authors provide a historical overview and current analysis of Maineâs food system, highlighting encouraging trends and opportunities for the state
Foehn winds in the McMurdo Dry Valleys, Antarctic: The origin of extreme warming events
Foehn winds resulting from topographic modification of airflow in the lee of mountain barriers are frequently experienced in the McMurdo Dry Valleys (MDVs) of Antarctica. Strong foehn winds in the MDVs cause dramatic warming at onset and have significant effects on landscape forming processes; however, no detailed scientific investigation of foehn in the MDVs has been conducted. As a result, they are often misinterpreted as adiabatically warmed katabatic winds draining from the polar plateau. Herein observations from surface weather stations and numerical model output from the Antarctic Mesoscale Prediction System (AMPS) during foehn events in the MDVs are presented. Results show that foehn winds in the MDVs are caused by topographic modification of south-southwesterly airflow, which is channeled into the valleys from higher levels. Modeling of a winter foehn event identifies mountain wave activity similar to that associated with midlatitude foehn winds. These events are found to be caused by strong pressure gradients over the mountain ranges of the MDVs related to synoptic-scale cyclones positioned off the coast of Marie Byrd Land. Analysis of meteorological records for 2006 and 2007 finds an increase of 10% in the frequency of foehn events in 2007 compared to 2006, which corresponds to stronger pressure gradients in the Ross Sea region. It is postulated that the intra- and interannual frequency and intensity of foehn events in the MDVs may therefore vary in response to the position and frequency of cyclones in the Ross Sea region
Symmetry superposition studied by surface second-harmonic generation.
The components of a third-rank Ď(2) tensor have been split into contributions due to 1-fold, 2-fold, 3-fold, and â-fold or isotropic rotation axes for a surface of Cs symmetry. Theoretical analysis of the rotation patterns obtained by the surface second-harmonic (SH) generation indicates that a complete symmetry analysis cannot be performed without knowledge of the relevant distribution functions. Rotation axes of lower symmetry create via ââovertonesââ or ââharmonicsââ contributions apparent in the analysis of the rotation axes of higher symmetry. An experimental example is the observation of structural changes of Au(111) surfaces in an aqueous electrolytic environment. Potential-dependent buildup and removal of a Au(111)-(1Ă23) surface could be monitored in situ and in real time. Symmetry analysis of the SH rotation patterns reveals both contributions due to a 3-fold axis due to the regular (1Ă1) structure and simultaneously a 1-fold and a 2-fold axis due to the (1Ă23) reconstruction
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