Order parameter and detection for crystallized dipolar bosons in lattices

We explore the ground-state properties of bosons with dipole-dipole interactions in a one-dimensional optical lattice. Remarkably, a crystallization process happens for strong dipolar interactions. Herein, we provide a detailed characterization and a way to measure the resulting crystal phase. Using the eigenvalues of the reduced one-body density matrix we define an order parameter that yields a phase diagram in agreement with an analysis of the density and two-body density. We demonstrate that the phase diagram can be detected experimentally using the variance of single-shot measurements.Comment: 6 pages, 3 figures. Supplementary Information included. Software available at http://ultracold.org

Low-lying dipole strengths for probable pp-wave one-neutron halos in the medium mass region

The one-neutron halos lying in the island of inversion around $N=20$ has provided the podium, to study the variation of total low-lying dipole strength with the neutron separation energy. We study three probable p-wave one-neutron halo candidates 31Ne and 34Na and 37Mg lying in the island of inversion. A simple analytic model has been used for the calculation of the total low-lying dipole strength for the medium mass p-wave one-neutron halos. A correction factor to this analytical model has been estimated with a realistic Woods-Saxon potential. A comparison of these analytic calculations has been made with the those performed by a finite-range distorted-wave Born approximation theory of the Coulomb dissociation. We also make an estimate of the one-neutron separation energies of 31Ne, 34Na and 37Mg.Comment: 7 pages latex, 4 figures, to appear in EPJ

Constraining Compact Object Formation with 2M0521

We show that the recently discovered binary 2M05215658+4359220 (2M0521), comprised of a giant star (GS) orbiting a suspected black hole (BH) in a ~80 day orbit, may be instrumental in shedding light on uncertain BH-formation physics and can be a test case for studying wind accretion models. Using binary population synthesis with a realistic prescription for the star formation history and metallicity evolution of the Milky Way, we analyze the evolution of binaries containing compact objects (COs) in orbit around GSs with properties similar to 2M0521. We find ~100-1000 CO-GS binaries in the Milky Way observable by Gaia, and 0-12 BH-GS and 0-1 neutron star-GS binaries in the Milky Way with properties similar to 2M0521. We find that all CO-GSs with Porb<5 yr, including 2M0521, go through a common envelope (CE) and hence form a class of higher mass analogs to white dwarf post-CE binaries. We further show how the component masses of 2M0521-like binaries depend strongly on the supernova-engine model we adopt. Thus, an improved measurement of the orbit of 2M0521, imminent with Gaia's third data release, will strongly constrain its component masses and as a result inform supernova-engine models widely used in binary population synthesis studies. These results have widespread implications for the origins and properties of CO binaries, especially those detectable by LIGO and LISA. Finally, we show that the reported X-ray non-detection of 2M0521 is a challenge for wind accretion theory, making 2M0521-like CO-GS binaries a prime target for further study with accretion models.Comment: 7 pages, 5 figures, Accepted for Publication in ApJ

Tied Versus Untied Foreign Aid: Consequences for a Growing Economy

This paper contrasts the effects of tied and untied foreign aid programs on the welfare and macroeconomic performance of a small open economy. We show that the acceptance of tied aid inevitably obligates the recipient economy to undertake certain internal structural adjustments, and the flexibility it possesses to undertake these adjustments eventually determines the effectiveness of the aid program. The economic consequences of tied and untied aid programs, their relative merits from a welfare standpoint, and the transitional dynamics depend crucially upon several characteristics of the recipient economy that summarize this flexibility. These include: (i) the costs of installing public capital relative to private capital (intertemporal adjustment costs), (ii) the substitutability between factors of production (intratemporal adjustment costs), (iii) the flexibility of labor supply (work effort), (iv) the recipient's degree of access to the world financial markets (capital market imperfections), and (v) the recipient's opportunities for co-financing infrastructure projects by domestic resourcesForeign aid, International transfers, Economic growth, Public investment

Application of edge-based finite elements and vector ABCs in 3D scattering

A finite element absorbing boundary condition (FE-ABC) solution of the scattering by arbitrary 3-D structures is considered. The computational domain is discretized using edge-based tetrahedral elements. In contrast to the node-based elements, edge elements can treat geometries with sharp edges, are divergence-less, and easily satisfy the field continuity condition across dielectric interfaces. They do, however, lead to a higher unknown count but this is balanced by the greater sparsity of the resulting finite element matrix. Thus, the computation time required to solve such a system iteratively with a given degree of accuracy is less than the traditional node-based approach. The purpose is to examine the derivation and performance of the ABC's when applied to 2-D and 3-D problems and to discuss the specifics of our FE-ABC implementation

A finite element boundary integral formulation for radiation and scattering by cavity antennas using tetrahedral elements

A hybrid finite element boundary integral formulation is developed using tetrahedral and/or triangular elements for discretizing the cavity and/or aperture of microstrip antenna arrays. The tetrahedral elements with edge based linear expansion functions are chosen for modeling the volume region and triangular elements are used for discretizing the aperture. The edge based expansion functions are divergenceless thus removing the requirement to introduce a penalty term and the tetrahedral elements permit greater geometrical adaptability than the rectangular bricks. The underlying theory and resulting expressions are discussed in detail together with some numerical scattering examples for comparison and demonstration

Strong CP violation and chiral symmetry breaking in hot and dense quark matter

We investigate chiral symmetry breaking and strong CP violation effects in the phase diagram of strongly interacting matter. We demonstrate the effect of strong CP violating terms on the phase structure at finite temperature and densities in a 3-flavor Nambu-Jona-Lasinio (NJL) model including the Kobayashi-Maskawa-t'Hooft (KMT) determinant term. This is investigated using an explicit structure for the ground state in terms of quark-antiquark condensates for both in the scalar and the pseudoscalar channels. CP restoring transition with temperature at zero baryon density is found to be a second order transition at $\theta = \pi$ while the same at finite chemical potential and small temperature turns out to be a first order transition. Within the model, the tri-critical point turns out to be $(T_c,\mu_c)\simeq(273,94)$ MeV at $\theta = \pi$ for such a transition.Comment: 10 pages, 12 figure