BBO and the Neutron-Star-Binary Subtraction Problem

The Big Bang Observer (BBO) is a proposed space-based gravitational-wave (GW) mission designed primarily to search for an inflation-generated GW background in the frequency range 0.1-1 Hz. The major astrophysical foreground in this range is gravitational radiation from inspiraling compact binaries. This foreground is expected to be much larger than the inflation-generated background, so to accomplish its main goal, BBO must be sensitive enough to identify and subtract out practically all such binaries in the observable universe. It is somewhat subtle to decide whether BBO's current baseline design is sufficiently sensitive for this task, since, at least initially, the dominant noise source impeding identification of any one binary is confusion noise from all the others. Here we present a self-consistent scheme for deciding whether BBO's baseline design is indeed adequate for subtracting out the binary foreground. We conclude that the current baseline should be sufficient. However if BBO's instrumental sensitivity were degraded by a factor 2-4, it could no longer perform its main mission. It is impossible to perfectly subtract out each of the binary inspiral waveforms, so an important question is how to deal with the "residual" errors in the post-subtraction data stream. We sketch a strategy of "projecting out" these residual errors, at the cost of some effective bandwidth. We also provide estimates of the sizes of various post-Newtonian effects in the inspiral waveforms that must be accounted for in the BBO analysis.Comment: corrects some errors in figure captions that are present in the published versio

Issues Relevant to C-H Activation at Platinum(II): Comparative Studies between Cationic, Zwitterionic, and Neutral Platinum(II) Compounds in Benzene Solution

Cationic late metal systems are being highly scrutinized due to their propensity to mediate so-called electrophilic C-H activation reactions. This contribution compares the reactivity of highly reactive cationic platinum(II) systems with structurally related but neutral species. Our experimental design exploits isostructural neutral and cationic complexes supported by bis(phosphine) ligands amenable to mechanistic examination in benzene solution. The data presented herein collectively suggests that neutral platinum complexes can be equally if not more reactive towards benzene than their cationic counter-parts. Moreover, a number of unexpected mechanistic distinctions between the two systems arise that help to explain their respective reactivity

Gravitational Redshift, Equivalence Principle, and Matter Waves

We review matter wave and clock comparison tests of the gravitational redshift. To elucidate their relationship to tests of the universality of free fall (UFF), we define scenarios wherein redshift violations are coupled to violations of UFF ("type II"), or independent of UFF violations ("type III"), respectively. Clock comparisons and atom interferometers are sensitive to similar effects in type II and precisely the same effects in type III scenarios, although type III violations remain poorly constrained. Finally, we describe the "Geodesic Explorer," a conceptual spaceborne atom interferometer that will test the gravitational redshift with an accuracy 5 orders of magnitude better than current terrestrial redshift experiments for type II scenarios and 12 orders of magnitude better for type III.Comment: Work in progress. 11 page

Quartic double solids with ordinary singularities

We study the mixed Hodge structure on the third homology group of a threefold which is the double cover of projective three-space ramified over a quartic surface with a double conic. We deal with the Torelli problem for such threefolds.Comment: 14 pages, presented at the Conference Arnol'd 7

Ultrafast Molecular Imaging by Laser Induced Electron Diffraction

We address the feasibility of imaging geometric and orbital structure of a polyatomic molecule on an attosecond time-scale using the laser induced electron diffraction (LIED) technique. We present numerical results for the highest molecular orbitals of the CO2 molecule excited by a near infrared few-cycle laser pulse. The molecular geometry (bond-lengths) is determined within 3% of accuracy from a diffraction pattern which also reflects the nodal properties of the initial molecular orbital. Robustness of the structure determination is discussed with respect to vibrational and rotational motions with a complete interpretation of the laser-induced mechanisms

Some comments on nˉp\bar n p-annihilation branching ratios into ππ\pi \pi-, KˉK\bar K K- and πη\pi \eta-channels

We give some remarks on the $\bar n p$-partial branching ratios in flight at low momenta of antineutron, measured by OBELIX collaboration. The comparison is made to the known branching ratios from the $p \bar p$-atomic states. The branching ratio for the reaction $\bar n p \to \pi^+\pi^0$ is found to be suppressed in comparison to what follows from the $p \bar p$-data. It is also shown, that there is no so called dynamic I=0-amplitude suppression for the process $N\bar N \to K\bar K$.Comment: 8 pages, LaTeX, no figure