Pseudoscalar-photon Interactions, Axions, Non-Minimal Extensions, and Their Empirical Constraints from Observations

Pseudoscalar-photon interactions were proposed in the study of the relations among equivalence principles. The interaction of pseudoscalar axion with gluons was proposed as a way to solve the strong CP problem. Subsequent proposal of axion as a dark matter candidate has been a focus of search. Motivation from superstring theories add to its importance. After a brief introduction and historical review, we present (i) the current status of our optical experiment using high-finesse Fabry-Perot resonant cavity - Q & A experiment - to detect pseudoscalar-photon interactions, (ii) the constraints on pseudoscalar-photon interactions from astrophysical and cosmological observations on cosmic polarization rotation, and (iii) theoretical models of non-minimal interactions of gravitational, electromagnetic and pseudoscalar (axion) fields, and their relevance to cosmology.Comment: 8 page

Direct Detection of the Primordial Inflationary Gravitational Waves

Inflationary cosmology is successful in explaining a number of outstanding cosmological issues including the flatness, the horizon and the relic issues. More spectacular is the experimental confirmation of the structure as arose from the inflationary quantum fluctuations. However, the physics in the inflationary era is unclear. Polarization observations of Cosmic Microwave Background (CMB) missions may detect the tensor mode effects of inflationary gravitational waves (GWs) and give an energy scale of inflation. To probe the inflationary physics, direct observation of gravitational waves generated in the inflationary era is needed. In this essay, we advocate that the direct observation of these GWs with sensitivity Omega-gw down to 10**(-23) is possible using present projected technology development if foreground could be separated.Comment: 6 pages, 1 figure, received an honorable mention in the 2009 Essay Competition of the Gravity Research Foundatio

Identification of Non-unitary triplet pairing in a heavy Fermion superconductor UPt_3

A NMR experiment recently done by Tou et al. on a heavy Fermion superconductor UPt$_3$ is interpreted in terms of a non-unitary spin-triplet pairing state which we have been advocating. The proposed state successfully explains various aspects of the seemingly complicated Knight shift behaviors probed for major orientations, including a remarkable d-vector rotation under weak fields. This entitles UPt$_3$ as the first example that a charged many body system forms a spin-triplet odd-par ity pairing at low temperatures and demonstrates unambiguously that the putative spin-orbit coupling in UPt$_3$ is weak.Comment: 4 pages, 2 eps figures, to be published in J. Phys. Soc. Jpn. 67 (1998) No.

Dynamical Screening and Superconducting State in Intercalated Layered Metallochloronitrides

An essential property of layered systems is the dynamical nature of the screened Coulomb interaction. Low energy collective modes appear as a consequence of the layering and provide for a superconducting-pairing channel in addition to the electron-phonon induced attractive interaction. We show that taking into account this feature allows to explain the high critical temperatures (Tc~26K) observed in recently discovered intercalated metallochloronitrides. The exchange of acoustic plasmons between carriers leads to a significant enhancement of the superconducting critical temperature that is in agreement with the experimental observations

Quasiparticle Interactions for f2^2-Impurity Anderson Model with Crystalline-Electric-Field: Numerical Renormalization Group Study

The aspect of the quasiparticle interaction of a local Fermi liquid, the impurity version of f$^2$-based heavy fermions, is studied by the Wilson numerical renormalization group method. In particular, the case of the f$^2$-singlet crystalline-electric-field ground state is investigated assuming the case of UPt$_3$ with the hexagonal symmetry. It is found that the interorbital interaction becomes larger than the intraorbital one in contrast to the case of the bare Coulomb interaction for the parameters relevant to UPt$_3$. This result offers us a basis to construct a microscopic theory of the superconductivity of UPt$_3$ where the interorbital interactions are expected to play important roles.Comment: 9 pages, 5 figure

Effect of Spin-Orbit Interaction in Spin-Triplet Superconductor: Structure of d{\bf d}-vector and Anomalous 17^{17}O-NQR Relaxation in Sr2_2RuO4_4

Supposing the spin-triplet superconducting state of Sr$_2$RuO$_4$, the spin-orbit (SO) coupling associated with relative motion in Cooper pairs is calculated by extending the method for the dipole-dipole coupling given by Leggett in the superfluid $^{3}$He. It is shown that the SO coupling works only in the equal-spin pairing (ESP) state to make the pair angular momentum $\hbar{\vec L}$ and the pair spin angular momentum ${\rm i}{\vec d}\times{\vec d}^{*}$ parallel with each other. The SO coupling gives rise to the internal Josephson effect in a chiral ESP state as in superfluid A-phase of $^3$He with a help of an additional anisotropy arising from SO coupling of atomic origin which works to direct the {\bf d}-vector into $ab$-plane. This resolves the problem of the anomalous relaxation of $^{17}$O-NQR and the structure of {\bf d}-vector in Sr$_2$RuO$_4$.Comment: Accepted for publication in J. Phys. Soc. Jpn. vol.79 (2010), No.2 (February issue); 18 pages, 2 figure

Improved Simulation of the Mass Charging for ASTROD I

The electrostatic charging of the test mass in ASTROD I (Astrodynamical Space Test of Relativity using Optical Devices I) mission can affect the quality of the science data as a result of spurious Coulomb and Lorentz forces. To estimate the size of the resultant disturbances, credible predictions of charging rates and the charging noise are required. Using the GEANT4 software toolkit, we present a detailed Monte Carlo simulation of the ASTROD I test mass charging due to exposure of the spacecraft to galactic cosmic-ray (GCR) protons and alpha particles (3He, 4He) in the space environment. A positive charging rate of 33.3 e+/s at solar minimum is obtained. This figure reduces by 50% at solar maximum. Based on this charging rate and factoring in the contribution of minor cosmic-ray components, we calculate the acceleration noise and stiffness associated with charging. We conclude that the acceleration noise arising from Coulomb and Lorentz effects are well below the ASTROD I acceleration noise limit at 0.1 mHz both at solar minimum and maximum. The coherent Fourier components due to charging are investigated, it needs to be studied carefully in order to ensure that these do not compromise the quality of science data in the ASTROD I mission.Comment: 20 pages, 14 figures, submitted to International Journal of Modern Physics

Actitudes y creencias anticonceptivas entre los adultos jóvenes: Contraceptive Attitudes among Hmong Young Adults in Rural California

Introduction: While different contraceptive attitudes have been reported among different ethnic groups inthe US, little if any research has been conducted to understand the reproductive health needs and attitudesamong Hmong young adults. To our knowledge, this is the first study to investigate the relationship amongcontraceptive perception of this community. Objective: The purpose of this research was to identify attitudesthat influence Hmong college students’ contraceptive practices. Methods: A campus-wide online survey wasused as part of the data collection at a midsize institution in Central California. The questionnaire was a 32-items scale instrument called Contraceptive Attitude Scale (CAS), developed by Dr. Black. Results: Three hundred and forty-four students successfully completed the 32-items scale instrument CAS, which measured general contraceptive attitudes among Hmong young adults in rural California. The data reveals a high prevalence of unmarried (85%) Hmong college students reporting being sexually active (67%), with 62% having at least one sexual partner over the past 12 months; however, only 36% reported to use condom compared to 58% who did not use condoms during the last time of sexual intercourse. Conclusion: The findings indicated statistically significant differences between groups on the characteristics of sexual partners, contraceptive methods, marital status, birthplace, primary language spoken at home, years spent in college and years lived in the United States. The findings greatly contribute to the understanding of factors that influence contraceptive choices among the Hmong college population. More importantly, the information is crucial in designing programs to promote contraceptive knowledge and practices that are specific to the Hmong.Introducción: Si bien se informaron diferencias en las actitudes anticonceptivas entre los diferentes gruposétnicos en los EE. UU., Se ha realizado poca o ninguna investigación para comprender las necesidades yactitudes de salud reproductiva entre los adultos jóvenes hmong. Hasta donde sabemos, este es el primerestudio que investiga la relación entre la percepción anticonceptiva de esta comunidad. Objetivo: El propósito de esta investigación fue identificar actitudes que influyen en las prácticas anticonceptivas de los estudiantes universitarios de Hmong.Métodos: Se utilizó una encuesta en línea en todo el campus como parte de la recopilación de datos en una institución mediana en California Central. El cuestionario era un instrumento a escala de 32 ítems llamado Escala de Actitud Anticonceptiva (CAS), desarrollado por el Dra. Black. Resultados: Trescientos cuarenta y cuatro estudiantes completaron con éxito el instrumento CAS de escala de 32 ítems, que midió las actitudes anticonceptivas generales entre los adultos jóvenes Hmong en las zonas rurales de California. Los datos revelan una alta prevalencia de estudiantes universitarios Hmong solteros (85%) que informan ser sexualmente activos (67%), con 62% teniendo al menos una pareja sexual en los últimos 12 meses; sin embargo, solo el 36% informó usar condón en comparación con el 58% que no usó condón durante la última vez que tuvo relaciones sexuales. Conclusión: Los resultados indicaron diferencias estadísticamente significativas entre los grupos en cuanto a las características de las parejas sexuales, los métodos anticonceptivos, el estado civil, el lugar de nacimiento, el idioma principal que se habla en el hogar, los años que pasaron en la universidad y los años que vivieron en los Estados Unidos. Los hallazgos contribuyen en gran medida a la comprensión de los factores que influyen en las elecciones de anticonceptivos entre la población universitaria de Hmong. Más importante aún, la información es crucial en el diseño de programas para promover el conocimiento y las prácticas anticonceptivas que son específicos del Hmong

Josephson Current between Triplet and Singlet Superconductors

The Josephson effect between triplet and singlet superconductors is studied. Josephson current can flow between triplet and singlet superconductors due to the spin-orbit coupling in the spin-triplet superconductor but it is finite only when triplet superconductor has $L_z=-S_z=\pm 1$, where $L_z$ and $S_z$ are the perpendicular components of orbital angular momentum and spin angular momentum of the triplet Cooper pairs, respectively. The recently observed temperature and orientational dependence of the critical current through a Josephson junction between UPt$_3$ and Nb is investigated by considering a non-unitary triplet state.Comment: 4 pages, no figure