Distribution of Non-uniform Demagnetization Fields in Paramagnetic Bulk Solids

A general calculation for the distribution of non-uniform demagnetization fields in paramagnetic bulk solids is described and the fields for various sample geometries are calculated. Cones, ellipsoids, paraboloids and hyperboloids with similar sample aspect ratios are considered. Significant differences in their demagnetization fields are observed. The calculation shows that the demagnetization field magnitudes decrease along the axis of symmetry (along $z$) where an externally applied magnetic field is aligned, and increase in the vicinity of the lateral surfaces with the largest field values found in the cone and the narrowest field distributions found in the hyperboloid. Application is made to the theoretical modeling of the $^{1}$H-NMR spectra of a single crystal of field-induced superconductor $\lambda$-(BETS)$_{2}$FeCl$_{4}$ with a rectangular sample geometry, providing a good fit to the measured NMR spectra. This calculation is also applicable to diamagnetic or ferromagnetic materials in general.Comment: 7 pages, 7 figures, submitted to Physical Review B (Corresponding author: [email protected]

Beating the Book: Are There Patterns in NFL Betting Lines?

Las Vegas sports books provide two even-money bets (not counting commission, or vigorish ) regarding National Football League games- the point-spread between each pair of teams and the total number of points scored by each pair of teams (the over-under ). Odds makers set the numbers ( lines ) for these two bets almost a week in advance of the games, and they may change these numbers throughout the week as new information becomes available regarding the teams or as bettors bet unequally on either side of the line. This study examines whether there are any predictable patterns in the betting lines over the course of the preceding week that bettors could exploit to improve their expected returns, including whether it would have been profitable to try for middles as the betting lines changed over the course of the week. We will also note whether during the years studied any simple betting strategy, such as betting on favorites, underdogs, home teams, or visiting teams, would have been profitable

Monopoly rents and price fixing in betting markets

Betting markets provide an ideal environment in which to examine monopoly power due to the availability of detailed information on product pricing. In this paper we argue that the pricing strategies of companies in the UK betting industry are likely to be an important source of monopoly rents, particularly in the market for forecast bets. Pricing in these markets are shown to be explicitly coordinated. Further, price information is asymmetrically biased in favor of producers. We find evidence, based on UK data, that pricing of CSF bets is characterized by a significantly higher markup than pricing of single bets. Although this differential can in part be explained by the preferences of bettors, it is reasonable to attribute a significant part of the differential as being due to monopoly power

Testing for efficiency in the New Zealand horse racetrack betting market a thesis in partial fulfilment of the requirements for the degree of Master of Applied Economics at Massey University

Using a large sample of New Zealand pari-mutuel horse race betting data, this study tests for market efficiency. This involves testing for weak form efficiency and an anomaly known as the favourite longshot bias. Additionally, a test developed by Henery (1985) is used to examine the extent to which bettors discount their losses. Also, two utility' estimations are calculated using the first three moments surrounding the distribution. Each test is performed twice, firstly with the odds at the close of the tote and secondly with the odds quoted 30 minutes before the tote closes. A number of previous studies are reviewed. The data set is discussed along with its limitations. An extensive description of the research methodology' is presented, followed by the results, interpretations and discussion. Many former studies have found that racetrack betting is not weak form efficient, but instead there exists a negative risk-return trade-off in the market. This study, exhibiting the negative risk-return trade-off and the favourite longshot bias, is consistent with previous studies. Using opening odds, there is much evidence to suggest that the favourite longshot bias exists 30 minutes before the tote closes but is essentially eliminated in the final 30 minutes of betting. The estimation of Henery's test is consistent with his results that bettors discount approximately 2% of their losses as 'not typical'. The implications of this are also discussed. The estimation of bettor's utility' functions shows that bettors are risk lovers and, contrary' to one study, the inclusion of the third moment is insufficient to prove bettors are in fact risk averse

An Experimental and Semi-Empirical Method to Determine the Pauli-Limiting Field in Quasi 2D Superconductors as applied to κ\kappa-(BEDT-TTF)2_2Cu(NCS)2_2: Strong Evidence of a FFLO State

We present upper critical field data for $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$ with the magnetic field close to parallel and parallel to the conducting layers. We show that we can eliminate the effect of vortex dynamics in these layered materials if the layers are oriented within 0.3 degrees of parallel to the applied magnetic field. Eliminating vortex effects leaves one remaining feature in the data that corresponds to the Pauli paramagnetic limit ($H_p$). We propose a semi-empirical method to calculate the $H_p$ in quasi 2D superconductors. This method takes into account the energy gap of each of the quasi 2D superconductors, which is calculated from specific heat data, and the influence of many body effects. The calculated Pauli paramagnetic limits are then compared to critical field data for the title compound and other organic conductors. Many of the examined quasi 2D superconductors, including the above organic superconductors and CeCoIn$_5$, exhibit upper critical fields that exceed their calculated $H_p$ suggesting unconventional superconductivity. We show that the high field low temperature state in $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$ is consistent with the Fulde Ferrell Larkin Ovchinnikov state.Comment: 8 pages, 9 figures, 10 years of dat

Role of anion size, magnetic moment, and disorder on the properties of the organic conductor kappa-(BETS)_2Ga_{1-x}Fe_{x}Cl_{4-y}_Br_{y}

Shubnikov-de Haas and angular dependent magnetoresistance oscillations have been used to explore the role of anion size, magnetic moment, and disorder in the organic conductors kappa-(BETS)_2GaBr_{4} and kappa-(BETS)_2FeCl_{2}_Br_{2} in the isomorphic class kappa-(BETS)_2Ga_{1-x}Fe_{x}Cl_{4-y}_Br_{y}. The results, combined with previous work, show correlations between the anion composition (Ga_{1-x}Fe_{x}Cl_{4-y}_Br_{y}) and the superconducting transition temperature, effective mass, Fermi surface topology, and the mean free path.Comment: 5 pages, 6 figure

Antiferromagnetic superconductors with effective mass anisotropy in magnetic fields

We derive critical field H_c2 equations for antiferromagnetic \textit{s}-wave, d_{x^2-y^2}-wave, and d_{xy}-wave superconductors with effective mass anisotropy in three dimensions, where we take into account (i) the Jaccarino-Peter mechanism of magnetic-field-induced superconductivity (FISC) at high fields, (ii) an extended Jaccarino-Peter mechanism that reduces the Pauli paramagnetic pair-breaking effect at low fields where superconductivity and an antiferromagnetic long-range order with a canted spin structure coexist, and (iii) the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO or LOFF) state. As an example, experimental phase diagrams observed in organic superconductor kappa-(BETS)_2FeBr_4 are theoretically reproduced. In particular, the upper critical field of low-field superconductivity is well reproduced without any additional fitting parameter other than those determined from the critical field curves of the FISC at high fields. Therefore, the extended Jaccarino-Peter mechanism seems to occur actually in the present compound. It is predicted that the FFLO state does not occur in the FISC at high fields in contrast to the compound lambda-(BETS)_2FeCl_4, but it may occur in low-field superconductivity for s-wave and d_{x^2-y^2}-wave pairings. We also briefly discuss a possibility of compounds that exhibit unconventional behaviors of upper critical fields.Comment: 11 pages, 9 figures, revtex

Have Betting Exchanges Corrupted Horse Racing?

Betting exchanges allow punters to bet on a horse to lose a race. This, many argue, has opened up the sport to a new form of corruption, where races will be deliberately lost in order to profit from betting. We examine whether anecdotal evidence of the fixing of horses to lose—of which there are many examples—is indicative of wider corruption. Following a “forensic economics” approach, we build an asymmetric information model of exchange betting and take it to betting data on 9,560 races run in 2013/2014. We find no evidence of the widespread corruption of horse racing by the betting exchanges

Electrons and Positrons in Cosmic Rays

This review concentrates on the results obtained, over the last ten years, on the astrophysics of high-energy cosmic ray electrons and positrons. The anomalies, observed in the data of recent experiments (possible bump in the electron spectrum and the PAMELA anomaly in the positron fraction) are discussed through the systematic use of simple analytical solutions of the transport equations for cosmic ray electrons. Three main ways of explaining the origin of the anomalies are considered: the conservative way supposing the positrons to be pure secondary particles; the nearby sources like pulsars origin; and the dark matter origin. This review discusses, also, the inability to select the pulsars model or the dark matter model to explain the electron anomalies on the basis of the electron spectra with the usual large energy binning ($\gtrsim15$). It is argued that the signature of nearby pulsars origin of the anomalies against the dark matter origin could be the fine structure of the cosmic ray electron spectrum predicted in the Malyshev et al. paper (2009) and which was observed in the data from the high-resolution ATIC experiment (2009-2011). To date, the high-resolution ATIC data was the only experimental result of this type published in the literature. Therefore, they should be tested by other experiments as soon as possible. Generally, there is, also, rather controversial situations between the data of the majority of recent experiments and, consequently, there is a noted urgent need for new high-precision and high-statistical experiments.Comment: LaTeX2e, 27 pages, 28 figures, invited paper for 23rd European Cosmic Ray Symposium (2012