Atypical Thermonuclear Supernovae from Tidally Crushed White Dwarfs

Suggestive evidence has accumulated that intermediate mass black holes (IMBH) exist in some globular clusters. As stars diffuse in the cluster, some will inevitable wander sufficiently close to the hole that they suffer tidal disruption. An attractive feature of the IMBH hypothesis is its potential to disrupt not only solar-type stars but also compact white dwarf stars. Attention is given to the fate of white dwarfs that approach the hole close enough to be disrupted and compressed to such extent that explosive nuclear burning may be triggered. Precise modeling of the dynamics of the encounter coupled with a nuclear network allow for a realistic determination of the explosive energy release, and it is argued that ignition is a natural outcome for white dwarfs of all varieties passing well within the tidal radius. Although event rates are estimated to be significantly less than the rate of normal Type Ia supernovae, such encounters may be frequent enough in globular clusters harboring an IMBH to warrant a search for this new class of supernova.Comment: 13 pages, 4 figures, ApJ, accepte

High-precision laser spectroscopy of the CO A1Π^1\Pi - X1Σ+^1\Sigma^+ (2,0), (3,0) and (4,0) bands

High-precision two-photon Doppler-free frequency measurements have been performed on the CO A$^1\Pi$ - X$^1\Sigma^+$ fourth-positive system (2,0), (3,0), and (4,0) bands. Absolute frequencies of forty-three transitions, for rotational quantum numbers up to $J = 5$, have been determined at an accuracy of $1.6\times10^{-3}$ cm$^{-1}$, using advanced techniques of two-color 2+1' resonance-enhanced multi-photon ionization, Sagnac interferometry, frequency-chirp analysis on the laser pulses, and correction for AC-Stark shifts. The accurate transition frequencies of the CO A$^1\Pi$ - X$^1\Sigma^+$ system are of relevance for comparison with astronomical data in the search for possible drifts of fundamental constants in the early universe. The present accuracies in laboratory wavelengths of $\Delta\lambda/\lambda = 2 \times 10^{-8}$ may be considered exact for the purpose of such comparisons.Comment: 13 pages, 6 figures, The Journal of Chemical Physics (2015) accepte

The symmetry of the spin Hamiltonian in herbertsmithite, a spin-1/2 kagom\'{e} lattice

We present magnetization measurements on oriented powder of ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$ along and perpendicular to the orienting field. We find a dramatic difference in the magnetization between the two directions. It is biggest at low measurement fields $H$ or high temperatures. We show that the difference at high temperatures must emerge from Ising-like exchange anisotropy. This allows us to explain muon spin rotation data at $T\to 0$ in terms of an exotic ferromagnetic ground state.Comment: 5 pages, 5 figure

Steroid-Induced Psychosis Presenting as Alice in Wonderland Syndrome

A 40 year old overweight male with a history of bronchial asthma, hypertension, and “schizophrenia” was admitted for intractable bronchial asthma. He did not have a history of drug or alcohol use. Upon admission, he was treated with high doses of IV methyl prednisone, oral prednisone, and triamcinolone inhaler. He developed complex visual hallucinations which decreased following tapering of prednisone and discontinuation of the triamcinolone. EEG showed diffuse slowing suggesting a toxic metabolic state

Continuity of Local Time: An applied perspective

Continuity of local time for Brownian motion ranks among the most notable mathematical results in the theory of stochastic processes. This article addresses its implications from the point of view of applications. In particular an extension of previous results on an explicit role of continuity of (natural) local time is obtained for applications to recent classes of problems in physics, biology and finance involving discontinuities in a dispersion coefficient. The main theorem and its corollary provide physical principles that relate macro scale continuity of deterministic quantities to micro scale continuity of the (stochastic) local time.Comment: To appear in: "The fascination of Probability, Statistics and Their Applications. In honour of Ole E. Barndorff-Nielsen on his 80th birthday

Degenerate four-wave mixing in triply-resonant Kerr cavities

We demonstrate theoretical conditions for highly-efficient degenerate four-wave mixing in triply-resonant nonlinear (Kerr) cavities. We employ a general and accurate temporal coupled-mode analysis in which the interaction of light in arbitrary microcavities is expressed in terms a set of coupling coefficients that we rigorously derive from the full Maxwell equations. Using the coupled-mode theory, we show that light consisting of an input signal of frequency $\omega_0-\Delta \omega$ can, in the presence of pump light at $\omega_0$, be converted with quantum-limited efficiency into an output shifted signal of frequency $\omega_0 + \Delta \omega$, and we derive expressions for the critical input powers at which this occurs. We find that critical powers in the order of 10mW assuming very conservative cavity parameters (modal volumes $\sim10$ cubic wavelengths and quality factors $\sim1000$. The standard Manley-Rowe efficiency limits are obtained from the solution of the classical coupled-mode equations, although we also derive them from simple photon-counting "quantum" arguments. Finally, using a linear stability analysis, we demonstrate that maximal conversion efficiency can be retained even in the presence of self- and cross-phase modulation effects that generally act to disrupt the resonance condition.Comment: 13 pages, 8 figures. To appear in Physical Review

Income Earning Potential versus Consumptive Amenities in Determining Ranchland Values

The relative importance of income earning potential versus consumptive values in setting ranchland prices is examined using a truncated hedonic model. The market value of New Mexico ranches is related to annual income earning potential and other ranch characteristics including ranch size, location, elevation, terrain, and the amount of deeded, public, and state trust land on the ranch. We found ranch income to be a statistically important determinant of land value, but yet a relatively small percentage of ranch value was explained by income earnings. Ranch location, scenic view, and the desirable lifestyle influenced ranch value more than ranch income.consumptive value, grazing fees, grazing permit value, hedonic model, land value, lifestyle agriculture, public land grazing, voluntary grazing permit buyout, Land Economics/Use,