Why Support the Occupy Movement?

I would like to provide a new angle on the Occupy Movement from a Christian point of view, specifically from the standpoint of my own work as a Christian theologian. Christians, I believe, should be supportive of the Occupy Movement and not simply for the obvious religious reasons. What are those obvious reasons? Christian concerns about social justice, Christian concerns especially for the poor, for all those disadvantaged and downtrodden, marginalized and harmed by forms of social exclusion and exploitation—such concerns clearly overlap with issues that the Occupy Movement has now brought to the forefront of our national consciousness: economic inequity and the economic plight of the 99 percent woefully underserved by our political and economic system since the financial crisis hit. Christianity and the Occupy Movement are closely aligned on these grounds of shared concern—concerns about injustice and about the economic disadvantage suffered by so many. But more than this, I believe that basic beliefs of Christianity contain an alternative vision of economic life that helps make sense of and pull together coherently the multiple strands of our economic and political predicament targeted for protest by the Occupy Movement—that’s what I want to argue now. I’ll try to show what this alternative Christian vision for our economic lives is, what the multiple concerns of the Occupy protest are, and how that Christian vision of economy brings those multiple strands of protest together

Observability of Dark Matter Substructure with Pulsar Timing Correlations

Dark matter substructure on small scales is currently weakly constrained, and its study may shed light on the nature of the dark matter. In this work we study the gravitational effects of dark matter substructure on measured pulsar phases in pulsar timing arrays (PTAs). Due to the stability of pulse phases observed over several years, dark matter substructure around the Earth-pulsar system can imprint discernible signatures in gravitational Doppler and Shapiro delays. We compute pulsar phase correlations induced by general dark matter substructure, and project constraints for a few models such as monochromatic primordial black holes (PBHs), and Cold Dark Matter (CDM)-like NFW subhalos. This work extends our previous analysis, which focused on static or single transiting events, to a stochastic analysis of multiple transiting events. We find that stochastic correlations, in a PTA similar to the Square Kilometer Array (SKA), are uniquely powerful to constrain subhalos as light as $\sim 10^{-13}~M_\odot$, with concentrations as low as that predicted by standard CDM.Comment: 45 pages, 12 figure

Using MOM:TIPS as a Short-Term Inservice with Four Day-Care Teachers

Four day-care teachers were introduced to Methods of Mothering: Training in Parenting Styles (MOM:TIPS), which is a parent-training program that has never been used with teachers. Modules addressing Self-Management, Disciplining/Monitoring, Nurturing, and Teaching Concepts were presented in an inservice training. Four workshops and available one-to-one consultations occurred over the period of one month. Each teacher was evaluated as a single-case in an A-B design using direct observations and self-report questionnaires. With Self-Management, each teacher reported that she makes daily schedules and follows a routine, but Teachers A, D indicated that they rarely or never used the steps involving more methodical, record-keeping methods. With Disciplining/Monitoring, Teachers B, C showed modest increases in Catching Good Behavior. With Nurturing, Teachers A, B were observed Smiling and engaging in Active Contact more often; Teacher C showed higher percentages of Active and Passive Contact during the Training Period. Teacher B’s increases continued at Follow-Up. A Spearman’s rho analysis found significant correlations between children’s positive responses and certain affectionate behaviors with each teacher. With Teaching Concepts, Teachers A, D used each step during Baseline; Teachers B, C were observed implementing the steps either during Training or Follow-Up. Each self-report indicated frequent implementation of most of the strategies and that overall teaching styles were generally congruent with MOM:TIPS. Methodological limitations are addressed and recommendations are provided

Detectability of Axion Dark Matter with Phonon Polaritons and Magnons

Collective excitations in condensed matter systems, such as phonons and magnons, have recently been proposed as novel detection channels for light dark matter. We show that excitation of i) optical phonon polaritons in polar materials in an ${\mathcal O}$(1 T) magnetic field (via the axion-photon coupling), and ii) gapped magnons in magnetically ordered materials (via the axion wind coupling to the electron spin), can cover the difficult-to-reach ${\mathcal O}$(1-100) meV mass window of QCD axion dark matter with less than a kilogram-year exposure. Finding materials with a large number of optical phonon or magnon modes that can couple to the axion field is crucial, suggesting a program to search for a range of materials with different resonant energies and excitation selection rules; we outline the rules and discuss a few candidate targets, leaving a more exhaustive search for future work. Ongoing development of single photon, phonon and magnon detectors will provide the key for experimentally realizing the ideas presented here.Comment: 35 pages, 5 figure

Pulsar Timing Probes of Primordial Black Holes and Subhalos

Pulsars act as accurate clocks, sensitive to gravitational redshift and acceleration induced by transiting clumps of matter. We study the sensitivity of pulsar timing arrays (PTAs) to single transiting compact objects, focusing on primordial black holes and compact subhalos in the mass range from $10^{-12} M _{\odot}$ to well above $100~M_\odot$. We find that the Square Kilometer Array can constrain such objects to be a subdominant component of the dark matter over this entire mass range, with sensitivity to a dark matter sub-component reaching the sub-percent level over significant parts of this range. We also find that PTAs offer an opportunity to probe substantially less dense objects than lensing because of the large effective radius over which such objects can be observed, and we quantify the subhalo concentration parameters which can be constrained.Comment: 18 pages, 6 figure

Multi-channel direct detection of light dark matter: theoretical framework

We present a unified theoretical framework for computing spin-independent direct detection rates via various channels relevant for sub-GeV dark matter — nuclear re- coils, electron transitions and single phonon excitations. Despite the very different physics involved, in each case the rate factorizes into the particle-level matrix element squared, and an integral over a target material- and channel-specific dynamic structure factor. We show how the dynamic structure factor can be derived in all three cases following the same procedure, and extend previous results in the literature in several aspects. For electron transitions, we incorporate directional dependence and point out anisotropic target materials with strong daily modulation in the scattering rate. For single phonon excitations, we present a new derivation of the rate formula from first principles for generic spin-independent couplings, and include the first calculation of phonon excitation through electron couplings. We also discuss the interplay between single phonon excitations and nuclear recoils, and clarify the role of Umklapp processes, which can dominate the single phonon production rate for dark matter heavier than an MeV. Our results highlight the complementarity between various search channels in probing different kinematic regimes of dark matter scattering, and provide a common reference to connect dark matter theories with ongoing and future direct detection experiments

Detecting Light Dark Matter with Magnons

Scattering of light dark matter with sub-eV energy deposition can be detected with collective excitations in condensed matter systems. When dark matter has spin-independent couplings to atoms or ions, it has been shown to efficiently excite phonons. Here we show that, if dark matter couples to the electron spin, magnon excitations in materials with magnetic dipole order offer a promising detection path. We derive general formulae for single magnon excitation rates from dark matter scattering, and demonstrate as a proof of principle the projected reach of a yttrium iron garnet target for several dark matter models with spin-dependent interactions. This highlights the complementarity of various collective excitations in probing different dark matter interactions

Observability of dark matter substructure with pulsar timing correlations

Dark matter substructure on small scales is currently weakly constrained, and its study may shed light on the nature of the dark matter. In this work we study the gravitational effects of dark matter substructure on measured pulsar phases in pulsar timing arrays (PTAs). Due to the stability of pulse phases observed over several years, dark matter substructure around the Earth-pulsar system can imprint discernible signatures in gravitational Doppler and Shapiro delays. We compute pulsar phase correlations induced by general dark matter substructure, and project constraints for a few models such as monochromatic primordial black holes (PBHs), and Cold Dark Matter (CDM)-like NFW subhalos. This work extends our previous analysis, which focused on static or single transiting events, to a stochastic analysis of multiple transiting events. We find that stochastic correlations, in a PTA similar to the Square Kilometer Array (SKA), are uniquely powerful to constrain subhalos as light as ~ 10⁻¹³ M⊙, with concentrations as low as that predicted by standard CDM