2,906 research outputs found
Uniqueness of static spherically symmetric vacuum solutions in the IR limit of Ho\v{r}ava-Lifshitz gravity
We investigate static spherically symmetric vacuum solutions in the IR limit
of projectable nonrelativistic quantum gravity, including the renormalisable
quantum gravity recently proposed by Ho\v{r}ava. It is found that the
projectability condition plays an important role. Without the cosmological
constant, the spacetime is uniquely given by the Schwarzschild solution. With
the cosmological constant, the spacetime is uniquely given by the Kottler
(Schwarzschild-(anti) de Sitter) solution for the entirely vacuum spacetime.
However, in addition to the Kottler solution, the static spherical and
hyperbolic universes are uniquely admissible for the locally empty region, for
the positive and negative cosmological constants, respectively, if its
nonvanishing contribution to the global Hamiltonian constraint can be
compensated by that from the nonempty or nonstatic region. This implies that
static spherically symmetric entirely vacuum solutions would not admit the
freedom to reproduce the observed flat rotation curves of galaxies. On the
other hand, the result for locally empty regions implies that the IR limit of
nonrelativistic quantum gravity theories does not simply recover general
relativity but includes it.Comment: 10 pages, accepted for publication in International Journal of Modern
Physics
Physics at the Linear Collider
The physics at the planned colliders is discussed around three main
topics corresponding to different manifestations of symmetry breaking:
physics in the no Higgs scenario, studies of the properties of the Higgs and
precision tests of SUSY. A comparison with the LHC is made for all these cases.
The mode of the linear collider will also be reviewed.Comment: 31 pages, 12 figures. Invited talk given at the Fifth Workshop on
High Energy Physics Phenomenology, Inter-University Centre for Astronomy and
Astrophysics, Pune, India, January 12 - 26, 199
Electron-Transport Properties of Na Nanowires under Applied Bias Voltages
We present first-principles calculations on electron transport through Na
nanowires at finite bias voltages. The nanowire exhibits a nonlinear
current-voltage characteristic and negative differential conductance. The
latter is explained by the drastic suppression of the transmission peaks which
is attributed to the electron transportability of the negatively biased plinth
attached to the end of the nanowire. In addition, the finding that a voltage
drop preferentially occurs on the negatively biased side of the nanowire is
discussed in relation to the electronic structure and conduction.Comment: 4 pages, 6 figure
Local ras and ros in the hypertrophic differentiation of chondrocytes
Newsletter of the Boston University School of Medicine, Student American Medical Association (SAMA
The Life Course of a Standard-Bearer: A Nonroyal Elite Burial at the Maya Archaeological Site of El Palmar, Mexico
Inspired by life course and osteobiography approaches, this article explores the life and death of an individual associated with the lakam title (âbannerâ in Colonial Yukatek Maya; thus, a âstandard-bearerâ), a nonroyal elite of Late Classic period Maya society (AD 600â850). Although these elites are depicted on polychrome vessels and carved monuments, little is known about their life experiences and mortuary practices. The present analysis centers on an individual found at Structure GZ1, a temple with a hieroglyphic stairway, at the Maya archaeological site of El Palmar, Mexico. Using osteological, archaeological, and epigraphic data as different lines of evidence, we examine the relationship of the individual to his affiliated group. At the time of interment, there were a wide array of social, cultural, and political events both shaping and reshaping the body and identities of the individual during a period of political turbulence.
Inspirado por los enfoques del curso de la vida y osteobiografĂa, este artĂculo explora la vida y muerte de un individuo asociado con el tĂtulo lakam (âbanderaâ en Yukateka maya colonial, por lo tanto, âabanderadoâ), o una Ă©lite no-real de la sociedad maya del perĂodo ClĂĄsico tardĂo (600â850 dC). Aunque estas Ă©lites se representan en las vasijas policromadas y monumentos tallados, casi no se saben sobre sus experiencias de vida y prĂĄctica mortuoria. El presente anĂĄlisis se centra en un individuo encontrado en la Estructura GZ1, un templo con una escalinata jeroglĂfica, en el sitio arqueolĂłgico maya de El Palmar, MĂ©xico. A travĂ©s de los datos osteolĂłgicos, arqueolĂłgicos y epigrĂĄficos como diferentes lĂneas de evidencia, examinamos la relaciĂłn del individuo con su grupo afiliado. En el momento del entierro, hubo una amplia gama de eventos sociales, culturales y polĂticos que dieron forma y remodelaron el cuerpo y las identidades del individuo durante un perĂodo de turbulencia polĂtica.Ye
Dynamically Induced Multi-Channel Kondo Effect
We study how the multi-channel Kondo effect is dynamically induced to affect
the photoemission and the inverse photoemission spectrum when an electron is
emitted from (or added to) the completely screened Kondo impurity with spin
. The spectrum thereby shows a power-law edge singularity characteristic
of the multi-channel Kondo model. We discuss this anomalous behavior by using
the exact solution of the multi-channel Kondo model and boundary conformal
field theory. The idea is further applied to the photoemission for quantum spin
systems, in which the edge singularity is controlled by the dynamically induced
overscreening effect with a mobile Kondo impurity.Comment: 6 pages, 4 figures, submitted to PR
Sneutrino Mass Measurements at e+e- Linear Colliders
It is generally accepted that experiments at an e+e- linear colliders will be
able to extract the masses of the selectron as well as the associated
sneutrinos with a precision of ~ 1% by determining the kinematic end points of
the energy spectrum of daughter electrons produced in their two body decays to
a lighter neutralino or chargino. Recently, it has been suggested that by
studying the energy dependence of the cross section near the production
threshold, this precision can be improved by an order of magnitude, assuming an
integrated luminosity of 100 fb^-1. It is further suggested that these
threshold scans also allow the masses of even the heavier second and third
generation sleptons and sneutrinos to be determined to better than 0.5%. We
re-examine the prospects for determining sneutrino masses. We find that the
cross sections for the second and third generation sneutrinos are too small for
a threshold scan to be useful. An additional complication arises because the
cross section for sneutrino pair to decay into any visible final state(s)
necessarily depends on an unknown branching fraction, so that the overall
normalization in unknown. This reduces the precision with which the sneutrino
mass can be extracted. We propose a different strategy to optimize the
extraction of m(\tilde{\nu}_\mu) and m(\tilde{\nu}_\tau) via the energy
dependence of the cross section. We find that even with an integrated
luminosity of 500 fb^-1, these can be determined with a precision no better
than several percent at the 90% CL. We also examine the measurement of
m(\tilde{\nu}_e) and show that it can be extracted with a precision of about
0.5% (0.2%) with an integrated luminosity of 120 fb^-1 (500 fb^-1).Comment: RevTex, 46 pages, 15 eps figure
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