Storage and Retrieval of Thermal Light in Warm Atomic Vapor

We report slowed propagation and storage and retrieval of thermal light in warm rubidium vapor using the effect of electromagnetically-induced transparency (EIT). We first demonstrate slowed-propagation of the probe thermal light beam through an EIT medium by measuring the second-order correlation function of the light field using the Hanbury-Brown$-$Twiss interferometer. We also report an experimental study on the effect of the EIT slow-light medium on the temporal coherence of thermal light. Finally, we demonstrate the storage and retrieval of thermal light beam in the EIT medium. The direct measurement of the photon number statistics of the retrieved light field shows that the photon number statistics is preserved during the storage and retrieval process.Comment: 4 pages, 4 figure

Reversing the Weak Quantum Measurement for a Photonic Qubit

We demonstrate the conditional reversal of a weak (partial-collapse) quantum measurement on a photonic qubit. The weak quantum measurement causes a nonunitary transformation of a qubit which is subsequently reversed to the original state after a successful reversing operation. Both the weak measurement and the reversal operation are implemented linear optically. The state recovery fidelity, determined by quantum process tomography, is shown to be over 94% for partial-collapse strength up to 0.9. We also experimentally study information gain due to the weak measurement and discuss the role of the reversing operation as an information erasure

On the Chaos Bound in Rotating Black Holes

We study out-of-time-order correlators (OTOCs) of rotating BTZ black holes using two different approaches: the elastic eikonal gravity approximation, and the Chern-Simons formulations of 3-dimensional gravity. Within both methods the OTOC is given as a sum of two contributions, corresponding to left and right moving modes. The contributions have different Lyapunov exponents, $\lambda_L^{\pm}=\frac{2\pi}{\beta}\frac{1}{1\mp \ell \Omega}$, where $\Omega$ is the angular velocity and $\ell$ is the AdS radius. Since $\lambda_L^{-} \leq \frac{2\pi}{\beta} \leq \lambda_L^{+}$, there is an apparent contradiction with the chaos bound. We discuss how the result can be made consistent with the chaos bound if one views $\beta_{\pm}=\beta(1\mp \ell \Omega)$ as the effective inverse temperatures of the left and right moving modes.Comment: 35 pages, 2 figures. v2: references added, typos corrected, and clarifications added to the discussion sectio

NMR study on the stability of the magnetic ground state in MnCr2{}_2O4{}_4

The canting angles and fluctuation of the magnetic ion spins of spinel oxide MnCr${}_2$O${}_4$ were studied by nuclear magnetic resonance (NMR) at low temperatures, which has a collinear ferrimagnetic order below $T_C$ and a ferrimagnetic spiral order below $T_s < T_C$. Contrary to previous reports, only one spin canting angle of Cr ions was observed. The spin canting angles of Mn and Cr ions in the ferrimagnetic spiral obtained at a liquid-He temperature were 43\,^{\circ} and 110\,^{\circ}, respectively. The nuclear spin-spin relaxation was determined by the Suhl-Nakamura interaction at low temperatures but the relaxation rate $T_2^{-1}$ increases rapidly as the temperature approaches $T_s$. This indicates that the fluctuation of the spiral component becomes faster as the temperature increases but not fast enough to leave an averaged hyperfine field to nuclei in the time scale of nuclear spin precession in the ferrimagnetic phase, which is on the order of $10^{-8}$ s. The spiral volume fraction measured for various temperatures reveals that the collinear and the spiral ferrimagnetic phases are mixed below the transition temperature of the spiral order. The temperature hysteresis in the volume fraction implies that this transition has first-order characteristics.Comment: 13 pages, 5 figure

POTENTIAL FOR UTILIZING NATIONAL TRUST MOVEMENT TO PRESERVE TOURISM RESOURCES: A CASE STUDY OF THE UNITED STATES, JAPAN, AND SOUTH KOREA

The tourism industry should consider the preservation of natural and cultural resources because these resources are important as attractions or background to attractions in many popular travel destinations. Regarding environmental conservation and preservation, nongovernmental organizations (NGOs) such as national trusts (NTs) or land trusts (LTs) are playing a major role. Therefore, it was assumed that the members of the NT/LT movement and tourism entities may make good partners in natural and cultural resource preservation and sustainable tourism development. Unpublished secondary data review and in-depth interview skills were utilized to investigate detailed collaborative cases involving tourism entities and LTs in the U.S, and tourism entities and NTs in Japan, and South Korea. The U.S. LTs, Japanese NTs, and Korean NTs mentioned various types of partnership with tourism entities. They explained the cases of partnership with the purpose of fundraising, public relations, direct land and cultural resource conservation, member’s benefits, and mutual advocacy. NT/LT organizations have begun to consider tourism as their partner for promoting natural and cultural resource preservation. Moreover, tourism has begun to recognize the value in promoting natural and cultural resource awareness, as a means of preserving tourism resources. The results from this study emphasize the convergent needs and goals of LTs/NTs and tourism regarding natural resource conservation. In a cooperative arrangement, the partnership between LTs/NTs and tourism entities would diversify revenue sources and increase public awareness.Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Sciences in the Department of Recreation, Park, and Tourism Studies School of Public Health Indiana Universit

Experimental verification of the commutation relation for Pauli spin operators using single-photon quantum interference

We report experimental verification of the commutation relation for Pauli spin operators using quantum interference of the single-photon polarization state. By superposing the quantum operations $\sigma_z \sigma_x$ and $\sigma_x \sigma_z$ on a single-photon polarization state, we have experimentally implemented the commutator, $[\sigma_{z}, \sigma_{x}]$, and the anticommutator, $\{\sigma_{z}, \sigma_{x}\}$, and have demonstrated the relative phase factor of $\pi$ between $\sigma_z \sigma_x$ and $\sigma_x \sigma_z$ operations. The experimental quantum operation corresponding to the commutator, $[\sigma_{z}, \sigma_{x}]=k\sigma_y$, showed process fidelity of 0.94 compared to the ideal $\sigma_y$ operation and $|k|$ is determined to be $2.12\pm0.18$.Comment: 4pages, 3 figure

Motivos trabajo inicial y la desmotivación en la enseñanza del inglés como lengua ex-­ tranjera: Los casos de los profesores coreanos

In order to broaden understanding of English as a foreign language (EFL) tea-­ cher motivation, this study examines Korean EFL teachers’ initial job motives and demotiva-­ ting factors. Four psychological constructs emerged regarding initial career motives: Global Orientation, Job Security, Altruism, and Ought-­to Self. Among the constructs, global orien-­ tation proved to be the most popular reason for choosing an EFL teaching career. This study also showed three constructs for detrimental factors on EFL teacher motivation: Obstacles to Communicative Language Teaching, Inadequate Administrative Support, and Lack of Social Recognition. It was shown that obstacles to communicative language teaching contributed to the greatest demotivation.Para la comprensión de inglés como lengua extranjera (EFL) motivación del profesorado, este estudio examina motivos de trabajo inicial y factores desmotivadores de los profesores coreanos. Cuatro constructos psicológicos surgieron con respecto a los moti-­ vos de trabajo inicial: orientación global, seguridad en el empleo, altruismo, y Ought-­to Self. Entre las constructos, orientación global resultó para ser la razón más popular para elegir una carrera de enseñanza de inglés como lengua extranjera. Este estudio también mostró tres constructos de factores perjudiciales en EFL motivación del profesorado: Los obstáculos de enseñanza de ingles como lengua extranjera. Este estudio también mostro tres constructores de factores perjudiciales en EFL motivación del profesorado: Los obstáculos de enseñanza comunicativa, la insuficiencia de apoyo administrativo, y la falta de reconocimiento social. Se ha demostrado que los obstáculos en enseñanza comunicativa ha contribuido a la mayor desmotivación