Topological flatness of local models for ramified unitary groups. I. The odd dimensional case

Local models are certain schemes, defined in terms of linear-algebraic moduli problems, which give \'etale-local neighborhoods of integral models of certain p-adic PEL Shimura varieties defined by Rapoport and Zink. When the group defining the Shimura variety ramifies at p, the local models (and hence the Shimura models) as originally defined can fail to be flat, and it becomes desirable to modify their definition so as to obtain a flat scheme. In the case of unitary similitude groups whose localizations at Q_p are ramified, quasi-split GU_n, Pappas and Rapoport have added new conditions, the so-called wedge and spin conditions, to the moduli problem defining the original local models and conjectured that their new local models are flat. We prove a preliminary form of their conjecture, namely that their new models are topologically flat, in the case n is odd.Comment: Minor revisions, some of which incorporate suggestions of the referee. 27 page

Cruise Report 72-KB-15: Big game fisheries investigations

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Covariant Effective Field Theory for Nuclear Structure and Nuclear Currents

Recent progress in Lorentz-covariant quantum field theories of the nuclear many-body problem (quantum hadrodynamics or QHD) is discussed. The effective field theory studied here contains nucleons, pions, isoscalar scalar (\sigma) and vector (\omega) fields, and isovector vector (\rho) fields. The theory exhibits a nonlinear realization of spontaneously broken SU(2)_L \times SU(2)_R chiral symmetry and has three desirable features: it uses the same degrees of freedom to describe the nuclear currents and the strong-interaction dynamics, it satisfies the symmetries of the underlying theory of QCD, and its parameters can be calibrated using strong-interaction phenomena, like hadron scattering or the empirical properties of finite nuclei. Moreover, it has recently been verified that for normal nuclear systems, it is possible to expand the effective Lagrangian systematically in powers of the meson fields (and their derivatives) and to truncate the expansion reliably after the first few orders. Using a mean-field version of the energy functional, accurate quantitative results are obtained for the bulk and single-particle properties of medium- and heavy-mass nuclei. The importance of modern perspectives in effective field theory and density functional theory for understanding these successes of QHD is emphasized. The inclusion of hadronic electromagnetic structure and of nonanalytic terms in the energy functional is also considered briefly. As a further application, weak-interaction currents are studied in the QHD framework. The axial-vector current, evaluated through the leading order in the field expansion, satisfies both PCAC and the Goldberger--Treiman relation, and the corresponding vector and axial-vector charges satisfy the familiar chiral charge algebra to all orders in the pion field.Comment: 32 pages, 9 figures, LaTeX2e with svmult.cls and svmultphys.clo; invited lecture at 307. WE-Heraeus-Seminar, "Relativistic Structure Models for the Physics of Radioactive Nuclear Beams," 5/12-16/2003, Bad Honnef, Germany. Reference list put into correct order; four typos fixe

Kilonovae

The mergers of double neutron star (NS-NS) and black hole (BH)-NS binaries are promising gravitational wave (GW) sources for Advanced LIGO and future GW detectors. The neutron-rich ejecta from such merger events undergoes rapid neutron capture (r-process) nucleosynthesis, enriching our Galaxy with rare heavy elements like gold and platinum. The radioactive decay of these unstable nuclei also powers a rapidly evolving, supernova-like transient known as a "kilonova". Kilonovae provide an approximately isotropic electromagnetic counterpart to the GW signal, which also provides a unique and direct probe of an important, if not dominant, r-process site. This handbook reviews the history and physics of kilonovae, leading to the current paradigm of week-long emission with a spectral peak at near-infrared wavelengths. Using a simple light curve model to illustrate the basic physics, I introduce potentially important variations on this canonical picture, including: ~day-long optical ("blue") emission from lanthanide-free components of the ejecta; ~hours-long precursor UV/blue emission, powered by the decay of free neutrons in the outermost ejecta layers; and enhanced emission due to energy input from a long-lived central engine, such as an accreting BH or millisecond magnetar. I assess the prospects of detecting kilonovae following future GW detections of NS-NS/BH-NS mergers in light of the recent follow-up campaign of the LIGO binary BH-BH mergers.Comment: published in Living Reviews in Relativit

Uncovering Hidden Profiles; Managerial Interventions for Discovering Superior Decision Alternatives

A common reason for the use of teams in organizations is the idea that each individual can bring a unique perspective to the decision task; however, research shows that teams often fail to surface and use unique information to evaluate decision alternatives. Under a condition known as the hidden profile, each member uniquely possesses a critical clue needed to uncover the superior solution. Failure to share and adequately evaluate this information will result in poor decision quality. In order to mitigate this team decision-making bias, the present study utilizes experimental research to examine the impact of the devil’s advocacy technique on the decision quality of hidden profile teams. Results show that advocacy groups had higher decision qualities than groups under free discussion; however, advocacy teams also had higher levels of anger and lower levels of individual support for their group’s decision. As a result, while these teams selected the best solution, the presence of a devil’s advocate introduces conditions that may hinder the solution’s implementation. Furthermore, similar experiments with advocacy techniques suggest that the positive effect on decision quality found here is reduced in the presence of stronger hidden profiles