The Economics of 'Acting White'

This paper formalizes a sociological phenomenon entitled 'acting white'. The key idea is that individuals face a tension between signaling their type to the outside labor market and signaling their type to a peer group: signals that induce high wages can be signals that induce peer rejection. We prove three basic results: (1) there exists no equilibria in which all types of individuals adopt distinct educational investment levels; (2) when individuals are not too patient, all equilibria satisfying a standard refinement involve a binary partition of the type space in which all types accepted by the group pool on a common low education level and all types rejected by the group separate at distinctly higher levels of education with correspondingly higher wages; and (3) when individuals are very patient, there is an increase in the variation of education levels within the group and an increase in the variance of types deemed acceptable by the group. The more those involved discount the future, the more salient peer pressure becomes and the more homogenous groups become.

Quantum quenches in a spinor condensate

We discuss the ordering of a spin-1 condensate when quenched from its paramagnetic phase to its ferromagnetic phase by reducing magnetic field. We first elucidate the nature of the equilibrium quantum phase transition. Quenching rapidly through this transition reveals XY ordering either at a specific wavevector, or the `light-cone' correlations familiar from relativistic theories, depending on the endpoint of the quench. For a quench proceeding at a finite rate the ordering scale is governed by the Kibble-Zurek mechanism. The creation of vortices through growth of the magnetization fluctuations is also discussed. The long time dynamics again depends on the endpoint, conserving the order parameter in zero field, but not at finite field, with differing exponents for the coarsening of magnetic order. The results are discussed in the light of a recent experiment by Sadler \emph{et al.}Comment: Published versio

Male earnings inequality, women’s employment and family income inequality in Australia, 1982 – 2007

This paper uses cross-sectional data to examine the relationship between the growth in earnings inequality among men, changes in women’s earnings and changes in family income inequality in Australia between 1982 and 2007-08. Male earnings inequality increased substantially across this period, as did women’s participation in paid work. Our analysis shows that both impacted on family income inequality, which rose by a relatively small amount. We also show that the impact of changes in women’s employment and earnings on family income inequality changed over the study period. During the years associated with the Hawke-Keating Labor government (1982 to 1995-96), growth in women’s earnings pushed family income inequality higher. However, during the tenure of the Howard government (1995-96 to 2007-08) the pattern reversed, with continued growth in women’s earnings contributing a moderating influence on family income inequality. These findings deliver new evidence on the importance of trends in family formation and the correlation of husbands’ and wives’ earnings to the evolution of family income inequality. They also show the potential effects of a range of policy initiatives on this evolution

Male Earnings Inequality, Women’s Employment and Family Income Inequality in Australia, 1982 - 2007

This preliminary paper uses cross-sectional data to examine the relationship between the growth inearnings inequality among men and women, and changes in family income inequality in Australia between 1982 and 2007-08. Although male earnings inequality increased substantially across this period, change in family income inequality was less significant. Our analysis shows that women?s earnings played a role in moderating the effects of rising male earnings inequality on the inequality of family income. This effect increased between 1982 and 2007-08, reflecting a pattern of change in women?s employment across households with low and high male earnings. The effects of this pattern of change are currently under-researched in the Australian context. Results presented in this paper have significance for understandings not only of the relationship between women?s earnings and family income inequality, but also the relationship between the hours that women work and family income inequality

Weak Coulomb blockade effect in quantum dots

We develop the general non-equilibrium theory of transport through a quantum dot, including Coulomb Blockade effects via a 1/N expansion, where N is the number of scattering channels. At lowest order we recover the Landauer formula for the current plus a self-consistent equation for the dot potential. We obtain the leading corrections and compare with earlier approaches. Finally, we show that to leading and next leading order in 1/N there is no interaction correction to the weak localization, in contrast to previous theories, but consistent with experiments by Huibers et al. [Phys. Rev. Lett. 81, 1917 (1998)], where N=4.Comment: 4 pages, 2 figures. Published versio

Long wavelength spin dynamics of ferromagnetic condensates

We obtain the equations of motion for a ferromagnetic Bose condensate of arbitrary spin in the long wavelength limit. We find that the magnetization of the condensate is described by a non-trivial modification of the Landau-Lifshitz equation, in which the magnetization is advected by the superfluid velocity. This hydrodynamic description, valid when the condensate wavefunction varies on scales much longer than either the density or spin healing lengths, is physically more transparent than the corresponding time-dependent Gross-Pitaevskii equation. We discuss the conservation laws of the theory and its application to the analysis of the stability of magnetic helices and Larmor precession. Precessional instabilities in particular provide a novel physical signature of dipolar forces. Finally, we discuss the anisotropic spin wave instability observed in the recent experiment of Vengalattore et. al. (Phys. Rev. Lett. 100, 170403, (2008)).Comment: arXiv version contains additional Section V relevant to the experiment of Vengalattore et. al. (Phys. Rev. Lett. 100, 170403, (2008)

Change in Reporting the Funded Status of Pensions: Impact on Debt-Asset and Debt-Equity Ratios

In September 2006, the Financial Accounting Standards Board issued a new standard for pensions, referred to when issued as Statement of Financial Accounting Standards No. 158 Employers\u27 Accounting for Defined Benefit Pension and Other Postretirement Plans (FASB 2006) and currently referred to as Accounting Standards Codification (ASC) 715 Compensation—Retirement Benefits, 30 Defined Benefit Plans—Pension, 25 Recognition. The objective of the new standard is to increase understandability of financial statements and improve timeliness and representational faithfulness relating to the funded status of defined benefit pension plans. The results presented in this study demonstrate the impact the new standard has on debt-asset ratios and on debt-equity ratios. Accordingly, the new accounting standard causes some firms to experience a material deterioration in their financial position based on the debt-asset and debt-equity ratios. The new standard provides a more conservative and accurate reporting of the funded status of defined benefit pension plans and therefore more useful information to investors and creditors

Lyα\alpha at Cosmic Dawn with a Simulated Roman Grism Deep Field

The slitless grism on the Nancy Grace Roman Space Telescope will enable deep near-infrared spectroscopy over a wide field of view. We demonstrate Roman's capability to detect Ly$\alpha$ galaxies at $z>7$ using a multi-position-angle (PA) observational strategy. We simulate Roman grism data using a realistic foreground scene from the COSMOS field. We also input fake Ly$\alpha$ galaxies spanning redshift z=7.5-10.5 and a line-flux range of interest. We show how a novel data cube search technique -- CUBGRISM -- originally developed for GALEX can be applied to Roman grism data to produce a Ly$\alpha$ flux-limited sample without the need for continuum detections. We investigate the impact of altering the number of independent PAs and exposure time. A deep Roman grism survey with 25 PAs and a total exposure time of $70$hrs can achieve Ly$\alpha$ line depths comparable to the deepest $z=7$ narrow-band surveys ($L_{{\rm{Ly}}\alpha}\gtrsim10^{43}$erg s$^{-1}$). Assuming a null result, where the opacity of the intergalactic medium (IGM) remains unchanged from $z\sim7$, this level of sensitivity will detect $\sim400$ deg$^{-2}$ Ly$\alpha$ emitters from $z=7.25-8.75$. A decline from this expected number density is the signature of an increasing neutral hydrogen fraction and the onset of reionization. Our simulations indicate that a deep Roman grism survey has the ability to measure the timing and magnitude of this decline, allowing us to infer the ionization state of the IGM and helping us to distinguish between models of reionization.Comment: 11 pages, 7 figures, Submitted to Ap