Detecting Lensing-Induced Diffraction in Astrophysical Gravitational Waves

Gravitational waves emitted from compact binary coalescence can be subject to wave diffraction if they are gravitationally lensed by an intervening mass clump whose Schwarzschild timescale matches the wave period. Waves in the ground-based frequency band $f\sim 10$--$10^3\,$Hz are sensitive to clumps with masses $M_E \sim 10^2$--$10^3\,M_\odot$ enclosed within the impact parameter. These can be the central parts of low mass $M_L \sim 10^3$--$10^6\,M_\odot$ dark matter halos, which are predicted in Cold Dark Matter scenarios but are challenging to observe. Neglecting finely-tuned impact parameters, we focus on lenses aligned generally on the Einstein scale for which multiple lensed images may not form in the case of an extended lens. In this case, diffraction induces amplitude and phase modulations whose sizes $\sim 10\%$--$20\%$ are small enough so that standard matched filtering with unlensed waveforms do not degrade, but are still detectable for events with high signal-to-noise ratio. We develop and test an agnostic detection method based on dynamic programming, which does not require a detailed model of the lensed waveforms. For pseudo-Jaffe lenses aligned up to the Einstein radius, we demonstrate that a pair of fully upgraded aLIGO/Virgo detectors can extract diffraction imprints from binary black hole mergers out to $z_s \sim 0.2$--$0.3$. The prospect will improve dramatically for a third-generation detector for which binary black hole mergers out to $z_s \sim 2$--$4$ will all become valuable sources.Comment: 14 pages including references; 8 figures; comments are welcom

Study of Impurity-Helium Condensates Formed by Multishell Nanoclusters

Impurity-helium condensates (IHCs) are porous gel-like materials created by injecting a mixed beam of helium gas and an impurity gas into super fluid 4He. Van der Waals forces lead to the formation of clusters of impurities each surrounded by a thin layer of solid helium. Inside super fluid helium the clusters tend to aggregate into a gel-like structure with wide distribution of pore sizes. Matrix isolation of free radical impurities in IHCs leads to unusually high concentrations of these impurities. Impurity-helium condensates (IHCs) containing nitrogen and krypton atoms immersed in super fluid 4He have been studied via a CW electron spin resonance (ESR) technique. It was found that the addition of krypton atoms to the nitrogen-helium gas mixture used for preparation of IHCs increases efficiency of stabilization of nitrogen atoms. We have achieved high average (5x10^19 cm^-3) and local (2x10^21 cm^-3) concentrations of nitrogen atoms in krypton-nitrogen-helium condensates. High concentrations of nitrogen atoms achieved in IHCs provide an important step in the search for magnetic ordering effects at low temperatures. Impurity-helium condensates created by injection of hydrogen (deuterium) atoms and molecules as well as rare gas (RG) atoms (Ne and Kr) into super fluid 4He also have been studied via electron spin resonance (ESR) techniques. Measurements of the ground-state spectroscopic parameters of hydrogen and deuterium atoms show that the nanoclusters have a shell structure. H and D atoms reside in solid molecular layers of H2 and D2, respectively. By monitoring the recombination of H atoms in the collection of hydrogen-neon nanoclusters, we show that nanoclusters form a gel-like porous structure which enables the H atoms to be transported through the structure via percolation. Observation of percolation in the collection of nanoclusters containing stabilized hydrogen atoms opens new possibilities for a search for macroscopic collective quantum phenomena at ultralow temperatures accessible by a dilution refrigerator

Gravitational lensing of gravitational waves: A statistical perspective

In this paper, we study the strong gravitational lensing of gravitational waves (GWs) from a statistical perspective, with particular focus on the high frequency GWs from stellar binary black hole coalescences. These are most promising targets for ground-based detectors such as Advanced Laser Interferometer Gravitational Wave Observatory (aLIGO) and the proposed Einstein Telescope (ET) and can be safely treated under the geometrical optics limit for GW propagation. We perform a thorough calculation of the lensing rate, by taking account of effects caused by the ellipticity of lensing galaxies, lens environments, and magnification bias. We find that in certain GW source rate scenarios, we should be able to observe strongly lensed GW events once per year ($\sim1~\text{yr}^{-1}$) in the aLIGO survey at its design sensitivity; for the proposed ET survey, the rate could be as high as $\sim80~\text{yr}^{-1}$. These results depend on the estimate of GW source abundance, and hence can be correspondingly modified with an improvement in our understanding of the merger rate of stellar binary black holes. We also compute the fraction of four-image lens systems in each survey, predicting it to be $\sim30$ per cent for the aLIGO survey and $\sim6$ per cent for the ET survey. Finally, we evaluate the possibility of missing some images due to the finite survey duration, by presenting the probability distribution of lensing time delays. We predict that this selection bias will be insignificant in future GW surveys, as most of the lens systems ($\sim90$ per cent) will have time delays less than $\sim1$ month, which will be far shorter than survey durations.Comment: 10 pages, 5 figures, 1 table. Revised to match version published in MNRA

N-[4-(4-Fluoro­phen­yl)-5-hy­droxy­methyl-6-isopropyl­pyrimidin-2-yl]-N-methyl­methane­sulfonamide

In the title compound, C16H20FN3O3S, the pyrimidine and benzene rings are oriented at a dihedral angle of 38.8 (3)°. An intra­molecular C—H⋯O hydrogen bond occurs. The crystal structure is stabilized by O—H⋯N hydrogen bonds. In addition, C—H⋯O inter­actions are also present

Interplay between Chiral Charge Density Wave and Superconductivity in Kagome Superconductors: A Self-consistent Theoretical Analysis

Inspired by the recent discovery of a successive evolutions of electronically ordered states, we present a self-consistent theoretical analysis that treats the interactions responsible for the chiral charge order and superconductivity on an equal footing. It is revealed that the self-consistent theory captures the essential features of the successive temperature evolutions of the electronic states from the high-temperature ``triple-$Q$" $2\times 2$ charge-density-wave state to the nematic charge-density-wave phase, and finally to the low-temperature superconducting state coexisting with the nematic charge density wave. We provide a comprehensive explanation for the temperature evolutions of the charge ordered states and discuss the consequences of the intertwining of the superconductivity with the nematic charge density wave. Our findings not only account for the successive temperature evolutions of the ordered electronic states discovered in experiments but also provide a natural explanation for the two-fold rotational symmetry observed in both the charge-density-wave and superconducting states. Moreover, the intertwining of the superconductivity with the nematic charge density wave order may also be an advisable candidate to reconcile the divergent or seemingly contradictory experimental outcomes regarding the superconducting properties

1-Butyl-3-(1-naphtho­yl)-1H-indole

In the title mol­ecule, C23H21NO, the dihedral angle between the planes of the indole ring and naphthalene ring system is 68.8 (5)°