Fourth post-Newtonian effective-one-body Hamiltonians with generic spins

In a compact binary coalescence, the spins of the compact objects can have a significant effect on the orbital motion and gravitational-wave (GW) emission. For generic spin orientations, the orbital plane precesses, leading to characteristic modulations of the GW signal. The observation of precession effects is crucial to discriminate among different binary formation scenarios, and to carry out precise tests of General Relativity. Here, we work toward an improved description of spin effects in binary inspirals, within the effective-one-body (EOB) formalism, which is commonly used to build waveform models for LIGO and Virgo data analysis. We derive EOB Hamiltonians including the complete fourth post-Newtonian (4PN) conservative dynamics, which is the current state of the art. We place no restrictions on the spin orientations or magnitudes, or on the type of compact object (e.g., black hole or neutron star), and we produce the first generic-spin EOB Hamiltonians complete at 4PN order. We consider multiple spinning EOB Hamiltonians, which are more or less direct extensions of the varieties found in previous literature, and we suggest another simplified variant. Finally, we compare the circular-orbit, aligned-spin binding-energy functions derived from the EOB Hamiltonians to numerical-relativity simulations of the late inspiral. While finding that all proposed Hamiltonians perform reasonably well, we point out some interesting differences, which could guide the selection of a simpler, and thus faster-to-evolve EOB Hamiltonian to be used in future LIGO and Virgo inference studies

Magnetic Response of Magnetospirillum Gryphiswaldense

In this study we modelled and measured the U-turn trajectories of individual magnetotactic bacteria under the application of rotating magnetic fields, ranging in ampitude from 1 to 12 mT. The model is based on the balance between rotational drag and magnetic torque. For accurate verification of this model, bacteria were observed inside 5 m tall microfluidic channels, so that they remained in focus during the entire trajectory. From the analysis of hundreds of trajectories and accurate measurements of bacteria and magnetosome chain dimensions, we confirmed that the model is correct within measurement error. The resulting average rate of rotation of Magnetospirillum Gryphiswaldense is 0.74 +- 0.03 rad/mTs.Comment: 17 pages, 12 figure

Supersymmetric contributions to B -> D K and the determination of angle \gamma

We analyze supersymmetric contributions to B^- -> D^0 K^- and B^- ->\bar{D}^0 K^- processes. We investigate the possibility that supersymmetric CP violating phases can affect our determination for the angle \gamma in the unitary triangle of Cabibbo-Kobayashi-Maskaw mixing matrix. We calculate the gluino and chargino contributions to b--> u(\bar{c}s) and b-->c(\bar{u}s) transitions in a model independent way by using the mass insertion approximation method. We also revise the D^0 - \bar{D}^0 mixing constraints on the mass insertions between the first and second generations of the up sector. We emphasize that in case of negligible D^0 -\bar{D}^0 mixing, one should consider simultaneous contributions from more than one mass insertion in order to be able to obtain the CP asymmetries of these processes within their 1\sigma experimental range. However, with a large D^0-\bar{D}^0 mixing, one finds a significant deviation between the two asymmetries and it becomes natural to have them of order the central values of their experimental measurements.Comment: 20 page

Inflation in Supersymmetric SU(5)

We analyze the adjoint field inflation in supersymmetric (SUSY) SU(5) model. In minimal SUSY SU(5) hybrid inflation monopoles are produced at the end of inflation. We therefore explore the non-minimal model of inflation based on SUSY SU(5), like shifted hybrid, which provides a natural solution for the monopole problem. We find that the supergravity corrections with non-minimal Kahler potential are crucial to realize the central value of the scalar spectral index n_s ~ 0.96 consistent with the seven year WMAP data. The tensor to scalar ratio r is quite small, taking on values r < 10^{-5}. Due to R-symmetry massless SU(3) octet and SU(2) triplet Higgs bosons are present and could spoil for gauge coupling unification. To keep gauge coupling unification intact, light vector-like particles are added which are expected to be observed at LHC.Comment: 16 page

Solvolysis Rates in Aqueous-Organic Mixed Solvents: Part II - Kinetics of Alkaline Solvolysis of Monochloroacetate Ion in Water-Ethanol Solutions

1012-101

The Changing Role of Non-CO2 Greenhouse Gases

During the last century, the concentrations of several greenhouse gases have increased considerably - most notably carbon dioxide, methane and nitrous oxide. In addition, new, entirely man-made gases have been put into the atmosphere that also cause the greenhouse effect; these include the chlorofluorocarbons. Calculations have shown that during the last century the non-CO₂ greenhouse gases could together be almost as effective as the increase of carbon dioxide in causing global warming. These and similar gases were therefore included in the Kyoto Protocol to develop a comprehensive plan for controlling potentially unfavorable climatic change. Studies show however that the other gases, with few exceptions, are likely to play a smaller than expected role in future global warming. The most significant non-CO₂ manmade greenhouse gases are methane and nitrous oxide. Methane rose from 700 ppbv some 200 years ago to about 1750 ppbv in recent times, while nitrous oxide rose from about 285 ppbv to 318 ppbv over the same time. These trends made methane the most important gas for global warming after carbon dioxide. But now, the rate of increase of methane has slowed down considerably. Budget analyses suggest that we may not see major changes of concentrations in the future comparable to the trends of the last century. Thus the role of methane in future global warming may be less than expected earlier. Nitrous oxide on the other hand, has increased slowly but steadily during recent decades. It is likely to become more important in the future compared with methane. While other greenhouse gases such as the perfluorocarbons, sulfur hexafluoride and hydrochlorofluorocarbons are included in the Kyoto Protocol, these are present in such minute concentrations that it is unlikely that they will have an important role in future global warming