Hole-Doped Cuprate High Temperature Superconductors

Hole-doped cuprate high temperature superconductors have ushered in the modern era of high temperature superconductivity (HTS) and have continued to be at center stage in the field. Extensive studies have been made, many compounds discovered, voluminous data compiled, numerous models proposed, many review articles written, and various prototype devices made and tested with better performance than their nonsuperconducting counterparts. The field is indeed vast. We have therefore decided to focus on the major cuprate materials systems that have laid the foundation of HTS science and technology and present several simple scaling laws that show the systematic and universal simplicity amid the complexity of these material systems, while referring readers interested in the HTS physics and devices to the review articles. Developments in the field are mostly presented in chronological order, sometimes with anecdotes, in an attempt to share some of the moments of excitement and despair in the history of HTS with readers, especially the younger ones.Comment: Accepted for publication in Physica C, Special Issue on Superconducting Materials; 27 pages, 2 tables, 30 figure

Magnetic Moments of JP=3/2+J^P={3/2}^+ Pentaquarks

If the $J^P$ of $\Theta_5^+$ and $\Xi_5^{--}$ pentaquarks is really found to be ${1\over 2}^+$ by future experiments, they will be accompanied by $J^P={3\over 2}^+$ partners in some models. It is reasonable to expect that these $J^P={3\over 2}^+$ states will also be discovered in the near future with the current intensive experimental and theoretical efforts. We estimate $J^P={3/2}^+$ pentaquark magnetic moments using different models.Comment: 13 page

Pentaquark Magnetic Moments In Different Models

We calculate the magnetic moments of the pentaquark states from different models and compare our results with predictions of other groups.Comment: 17 pages, no figur

Heavy Pentaquarks

We construct the spin-flavor wave functions of the possible heavy pentaquarks containing an anti-charm or anti-bottom quark using various clustered quark models. Then we estimate the masses and magnetic moments of the $J^P={1\over 2}^+$ or ${3\over 2}^+$ heavy pentaquarks. We emphasize the difference in the predictions of these models. Future experimental searches at BESIII, CLEOc, BELLE, and LEP may find these interesting states

Transit premium and rent segmentation: A spatial quantile hedonic analysis of Shanghai Metro

When measuring the betterment effect of public transit, most of the existing econometric research tends to use residential property price data and to focus on the conditional mean rather than the conditional variance in terms of the implicit price premium paid for access to public transit. However, because property sale price partly reflects speculation on future capital gains, it sheds little light on the renters' willingness-to-pay for living near public transportation facilities, let alone the variation in rent premium for transit proximity. We in this paper employ a spatial quantile hedonic regression method to gauge the rental impact of metro stations on a large sample of two-bedroom-one-bathroom (2b1b) apartments across 2575 residential complex communities (or “xiaoqu” in mandarin Chinese) in Shanghai, China, as observed between December 2012 and January 2013. We find: a) a community’s geographic adjacency to the nearest Shanghai Metro station tends to correlate positively with the xiaoqu’s average asking rent of 2b1b apartments, indicating a significant rent premium for transit proximity; b) although the transit premium fluctuates across the different rent levels, the variation is statistically insignificant, suggesting no evidence of transit-induced segmentation of the local private residential rental market. Apart from its policy implications, this paper demonstrates a US-China comparative perspective and a novel spatial quantile regression approach to test the segmentation effect of mass transit in a dynamic urban housing market

High-pressure study of superconducting and non-superconducting single crystals of the same nominal composition Rb0.8Fe2Se2

Two single crystalline samples with the same nominal composition of Rb0.8Fe2Se2 prepared via slightly different precursor routes under the same thermal processing conditions were investigated at ambient and high pressures. One sample was found superconducting with a Tc of ~31 K without the previously reported resistivity-hump and the other was unexpectedly found to be a narrow-gap semiconductor. While the high pressure data can be understood in terms of pressure-induced variation in doping, the detailed doping effect on superconductivity is yet to be determined.Comment: 9 pages, 6 figure

Heavy and Light Pentaquark Chiral Lagrangian

Using the SU(3) flavor symmetry, we construct the chiral Lagrangians for the light and heavy pentaquarks. The correction from the nonzero quark is taken into account perturbatively. We derive the Gell-Mann$-$Okubo type relations for various pentaquark multiplet masses and Coleman-Glashow relations for anti-sextet heavy pentaquark magnetic moments. We study possible decays of pentaquarks into conventional hadrons. We also study the interactions between and within various pentaquark multiplets and derive their coupling constants in the symmetry limit. Possible kinematically allowed pionic decay modes are pointed out