Charge Gap in the One-Dimensional Extended Hubbard Model at Quarter Filling

We propose a new combined approach of the exact diagonalization, the renormalization group and the Bethe ansatz for precise estimates of the charge gap $\Delta$ in the one-dimensional extended Hubbard model with the onsite and the nearest-neighbor interactions $U$ and $V$ at quarter filling. This approach enables us to obtain the absolute value of $\Delta$ including the prefactor without ambiguity even in the critical regime of the metal-insulator transition (MIT) where $\Delta$ is exponentially small, beyond usual renormalization group methods and/or finite size scaling approaches. The detailed results of $\Delta$ down to of order of $10^{-10}$ near the MIT are shown as contour lines on the $U$-$V$ plane.Comment: 4 pages, 4 figure

The three-dimensional BF Model with Cosmological Term in the Axial Gauge

We quantize the three-dimensional $BF$-model using axial gauge conditions. Exploiting the rich symmetry-structure of the model we show that the Green-functions correspond to tree graphs and can be obtained as the unique solution of the Ward-Identities. Furthermore, we will show that the theory can be uniquely determined by symmetry considerations without the need of an action principle.Comment: one reference added, transmission errors correcte

Combined Analysis of Numerical Diagonalization and Renormalization Group methods for the One-Dimensional UU-VV Model at Quarter filling

The one-dimensional extended Hubbard model with both the on-site $U$ and the nearest neighbor $V$ interactions at quarter filling is studied by using a novel finite size scaling. We diagonalize finite size systems numerically and calculate the Luttinger-liquid parameter $K_{\rho}$ which is substituted into the renormalization group equation as an initial condition. It leads $K_\rho$ in the infinite size system and the result agrees very well with the available exact result with $U=\infty$. This approach also yields the charge gap in the insulating state near the metal-insulator transition where the characteristic energy becomes exponentially small and the usual finite size scaling is not applicable.Comment: 7 pages, 8 figures,submitted to PR

Detection of Water and/or Hydroxyl on Asteroid (16) Psyche

In order to search for evidence of hydration on M-type asteroid (16) Psyche, we observed this object in the 3 micron spectral region using the long-wavelength cross-dispersed (LXD: 1.9-4.2 micron) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). Our observations show that Psyche exhibits a 3 micron absorption feature, attributed to water or hydroxyl. The 3 micron absorption feature is consistent with the hydration features found on the surfaces of water-rich asteroids, attributed to OH- and/or H2O-bearing phases (phyllosilicates). The detection of a 3 micron hydration absorption band on Psyche suggests that this asteroid may not be metallic core, or it could be a metallic core that has been impacted by carbonaceous material over the past 4.5 Gyr. Our results also indicate rotational spectral variations, which we suggest reflect heterogeneity in the metal/silicate ratio on the surface of Psyche.Comment: 13 pages, 9 figures in Astronomical Journal, 201

Source of water in basins off southern California

Water temperature and salinity measurements from most of the 14 basins off southern California, when compared with older data, show no detectable changes. The water in each basin is nearly isothermal and isohaline from the bottom to near the sill depth...

Wave patterns off southern California

Mapping of wave trains during four flights over the ocean off southern California showed the consistent presence of a high 10-second swell from the westnorthwest, of one or two low 3- to 5-second swells from other westerly directions, and of local wind waves; occasionally a low 13-second swell from the west and southwest was also present. Islands reduce the height of swells but produce little discernable crossswell in their lee...

Emotion and Inhibition: Pride Versus Happiness

The central question of my thesis is how different positive emotions affect inhibition. Katzir, Eyal, Meiran, and Kessler (2010) addressed this question using an antisaccade task and found that happiness decreased inhibition compared to pride, which they attribute to the links between pride and long-term goals and happiness and short-term goals. I attempted to generalize their results to a color-naming Stroop task and predicted that their results would not generalize because their study had little supporting research and their method had several limitations. I tested 45 students of the Claremont Colleges and found partial support for Katzir et al. Participants in the pride condition showed better inhibitory function than participants in the neutral condition, but I was unable to find differences in inhibitory function between participants in the pride and happiness or happiness and neutral conditions. The results suggest that pride improved inhibitory function compared to neutral emotion, but happiness had no effect. I conclude that further research is needed to confirm the supposed distinction between pride and happiness, the strength of the links between happiness, pride, and different goals, and the motivational role of emotion in inhibition

Oceanography on a Postage Stamp

Many postage stamps have designs that illustrate various aspects of oceanography. A representative selection of them reveals an international interest in the oceans