Neutrino Breakup of A=3 Nuclei in Supernovae

We extend the virial equation of state to include 3H and 3He nuclei, and predict significant mass-three fractions near the neutrinosphere in supernovae. While alpha particles are often more abundant, we demonstrate that energy transfer cross-sections for muon and tau neutrinos at low densities are dominated by breakup of the loosely-bound 3H and 3He nuclei. The virial coefficients involving A=3 nuclei are calculated directly from the corresponding nucleon-3H and nucleon-3He scattering phase shifts. For the neutral-current inelastic cross-sections and the energy transfer cross sections, we perform ab-initio calculations based on microscopic two- and three-nucleon interactions and meson-exchange currents.Comment: 6 pages, 2 figures, minor additions, to appear in Phys. Rev.

Topological Floquet-Thouless energy pump

We explore adiabatic pumping in the presence of periodic drive, finding a new phase in which the topologically quantized pumped quantity is energy rather than charge. The topological invariant is given by the winding number of the micromotion with respect to time within each cycle, momentum, and adiabatic tuning parameter. We show numerically that this pump is highly robust against both disorder and interactions, breaking down at large values of either in a manner identical to the Thouless charge pump. Finally, we suggest experimental protocols for measuring this phenomenon.Comment: 4 pages, 4 figures. Minor replacements and references adde

Iterative Temporal Motion Planning for Hybrid Systems in Partially Unknown Environments

This paper considers the problem of motion planning for a hybrid robotic system with complex and nonlinear dynamics in a partially unknown environment given a temporal logic specification. We employ a multi-layered synergistic framework that can deal with general robot dynamics and combine it with an iterative planning strategy. Our work allows us to deal with the unknown environmental restrictions only when they are discovered and without the need to repeat the computation that is related to the temporal logic specification. In addition, we define a metric for satisfaction of a specification. We use this metric to plan a trajectory that satisfies the specification as closely as possible in cases in which the discovered constraint in the environment renders the specification unsatisfiable. We demonstrate the efficacy of our framework on a simulation of a hybrid second-order car-like robot moving in an office environment with unknown obstacles. The results show that our framework is successful in generating a trajectory whose satisfaction measure of the specification is optimal. They also show that, when new obstacles are discovered, the reinitialization of our framework is computationally inexpensive

Lattice calculations for A=3,4,6,12 nuclei using chiral effective field theory

We present lattice calculations for the ground state energies of tritium, helium-3, helium-4, lithium-6, and carbon-12 nuclei. Our results were previously summarized in a letter publication. This paper provides full details of the calculations. We include isospin-breaking, Coulomb effects, and interactions up to next-to-next-to-leading order in chiral effective field theory.Comment: 38 pages, 11 figures, final publication versio

Correlation between Charge Inhomogeneities and Structure in Graphene and Other Electronic Crystalline Membranes

Only one atom thick and not inclined to lattice defects, graphene represents the ultimate crystalline membrane. However, its structure reveals unique features not found in other crystalline membranes, in particular the existence of ripples with wavelength of 100-300 Angstroms. Here, I trace the origin of this difference to the free electrons in the membrane. The deformation energy of the lattice creates a coupling between charge fluctuations and the structure, resulting in ripples on the membrane, correlated with charge inhomogeneities. In graphene this mechanism reproduces the experimental result for both charge puddles and ripples.Comment: Accepted for publication in PRB as Rapid Communicatio

Solar fusion cross sections II: the pp chain and CNO cycles

We summarize and critically evaluate the available data on nuclear fusion cross sections important to energy generation in the Sun and other hydrogen-burning stars and to solar neutrino production. Recommended values and uncertainties are provided for key cross sections, and a recommended spectrum is given for 8B solar neutrinos. We also discuss opportunities for further increasing the precision of key rates, including new facilities, new experimental techniques, and improvements in theory. This review, which summarizes the conclusions of a workshop held at the Institute for Nuclear Theory, Seattle, in January 2009, is intended as a 10-year update and supplement to Reviews of Modern Physics 70 (1998) 1265.Comment: 54 pages, 20 figures, version to be published in Reviews of Modern Physics; various typos corrected and several updates mad

Securitized volunteerism and neo-nationalism in Israel’s rural periphery

Contemporary volunteering is often considered a neoliberal phenomenon that has become prevalent in an era of post-national sentiments and individualism. Although it is frequently depicted as non-political, it may serve the promotion of political agendas, such as neo-nationalism, outside the traditional frame of the state and its institutions. This becomes particularly salient when non-governmental organizations practice volunteering in ways that undermine the state’s monopoly in the realms of security and public order. We conceptualize this tendency as securitized volunteering – instances of volunteering work that is promoted by, in this case non-state, organizations who are involved in voluntary security activities that are violent (or potentially violent). Drawing on an ethnographic study of the Israeli organization HaShomer HaChadash (The New Guard), this article demonstrates how agricultural and security volunteering is used to advance a neo-nationalist agenda that circumvents the state, and at the same time maintains an apolitical stance. This is achieved through the implementation of two corresponding forms of securitized volunteering – civilianization of security volunteerism and securitization of civilian volunteerism. Blurring the distinction between both forms enables the organization to attract supporters and volunteers that come from various social sectors and to reinforce its seemingly apolitical position and nationalist agenda