9,858 research outputs found
Envelope addressed to Mary Vansant
Envelope has a stamp, a return address, a mailing address and two cancellation stamps.https://scholars.fhsu.edu/tj_ks_territorial_docs/1000/thumbnail.jp
Experimental study of acoustic displays of flight parameters in a simulated aerospace vehicle
Evaluating acoustic displays of target location in target detection and of flight parameters in simulated aerospace vehicle
Non-Chern-Simons Topological Mass Generation in (2+1) Dimensions
By dimensional reduction of a massive BF theory, a new topological field
theory is constructed in (2+1) dimensions. Two different topological terms, one
involving a scalar and a Kalb-Ramond fields and another one equivalent to the
four-dimensional BF term, are present. We constructed two actions with these
topological terms and show that a topological mass generation mechanism can be
implemented. Using the non-Chern-Simons topological term, an action is proposed
leading to a classical duality relation between Klein-Gordon and Maxwell
actions. We also have shown that an action in (2+1) dimensions with the
Kalb-Ramond field is related by Buscher's duality transformation to a massive
gauge-invariant Stuckelberg-type theory.Comment: 8 pages, no figures, RevTE
On the Validity of the Tomonaga Luttinger Liquid Relations for the One-dimensional Holstein Model
For the one-dimensional Holstein model, we show that the relations among the
scaling exponents of various correlation functions of the Tomonaga Luttinger
liquid (LL), while valid in the thermodynamic limit, are significantly modified
by finite size corrections. We obtain analytical expressions for these
corrections and find that they decrease very slowly with increasing system
size. The interpretation of numerical data on finite size lattices in terms of
LL theory must therefore take these corrections into account. As an important
example, we re-examine the proposed metallic phase of the zero-temperature,
half-filled one-dimensional Holstein model without employing the LL relations.
In particular, using quantum Monte Carlo calculations, we study the competition
between the singlet pairing and charge ordering. Our results do not support the
existence of a dominant singlet pairing state.Comment: 7 page
The Spectrum of Pluto, 0.40 - 0.93 m I. Secular and longitudinal distribution of ices and complex organics
Context. During the last 30 years the surface of Pluto has been
characterized, and its variability has been monitored, through continuous
near-infrared spectroscopic observations. But in the visible range only few
data are available. Aims. The aim of this work is to define the Pluto's
relative reflectance in the visible range to characterize the different
components of its surface, and to provide ground based observations in support
of the New Horizons mission. Methods. We observed Pluto on six nights between
May and July 2014, with the imager/spectrograph ACAM at the William Herschel
Telescope (La Palma, Spain). The six spectra obtained cover a whole rotation of
Pluto (Prot = 6.4 days). For all the spectra we computed the spectral slope and
the depth of the absorption bands of methane ice between 0.62 and 0.90 m.
To search for shifts of the center of the methane bands, associated with
dilution of CH4 in N2, we compared the bands with reflectances of pure methane
ice. Results. All the new spectra show the methane ice absorption bands between
0.62 and 0.90 m. The computation of the depth of the band at 0.62 m
in the new spectra of Pluto, and in the spectra of Makemake and Eris from the
literature, allowed us to estimate the Lambert coefficient at this wavelength,
at a temperature of 30 K and 40 K, never measured before. All the detected
bands are blue shifted, with minimum shifts in correspondence with the regions
where the abundance of methane is higher. This could be indicative of a
dilution of CH4:N2 more saturated in CH4. The longitudinal and secular
variations of the parameters measured in the spectra are in accordance with
results previously reported in the literature and with the distribution of the
dark and bright material that show the Pluto's albedo maps from New Horizons.Comment: This manuscript may change and improve during the reviewing process.
The data reduction and calibration is reliable and has been checked
independently using different reduction approaches. The data will be made
publicily available when the paper is accepted. If you need them before,
please, contact the autho
Quantum Chemistry, Anomalous Dimensions, and the Breakdown of Fermi Liquid Theory in Strongly Correlated Systems
We formulate a local picture of strongly correlated systems as a Feynman sum
over atomic configurations. The hopping amplitudes between these atomic
configurations are identified as the renormalization group charges, which
describe the local physics at different energy scales. For a metallic system
away from half-filling, the fixed point local Hamiltonian is a generalized
Anderson impurity model in the mixed valence regime. There are three types of
fixed points: a coherent Fermi liquid (FL) and two classes of self-similar
(scale invariant) phases which we denote incoherent metallic states (IMS). When
the transitions between the atomic configurations proceed coherently at low
energies, the system is a Fermi liquid. Incoherent transitions between the low
energy atomic configurations characterize the incoherent metallic states. The
initial conditions for the renormalization group flow are determined by the
physics at rather high energy scales. This is the domain of local quantum
chemistry. We use simple quantum chemistry estimates to specify the basin of
attraction of the IMS fixed points.Comment: 12 pages, REVTE
Delocalization in Coupled Luttinger Liquids with Impurities
We study effects of quenched disorder on coupled two-dimensional arrays of
Luttinger liquids (LL) as a model for stripes in high-T_c compounds. In the
framework of a renormalization-group analysis, we find that weak inter-LL
charge-density-wave couplings are always irrelevant as opposed to the pure
system. By varying either disorder strength, intra- or inter-LL interactions,
the system can undergo a delocalization transition between an insulator and a
novel strongly anisotropic metallic state with LL-like transport. This state is
characterized by short-ranged charge-density-wave order, the superconducting
order is quasi long-ranged along the stripes and short-ranged in the
transversal direction.Comment: 6 pages, 5 figures, substantially extended and revised versio
Classical Phase Fluctuations in Incommensurate Peierls Chains
In the pseudogap regime of one-dimensional incommensurate Peierls systems,
fluctuations of the phase of the order parameter prohibit the emergence of
long-range order and generate a finite correlation length. For classical phase
fluctuations, we present exact results for the average electronic density of
states, the mean localization length, the electronic specific heat and the spin
susceptibility at low temperatures. Our results for the susceptibility give a
good fit to experimental data.Comment: 4 Revtex pages, 4 figures, submitted to Phys. Rev. Let
Superconductivity of a Metallic Stripe Embedded in an Antiferromagnet
We study a simple model for the metallic stripes found in
: two chain Hubbard ladder embedded in a static
antiferromagnetic environments. We consider two cases: a ``topological
stripe'', for which the phase of the Neel order parameter shifts by
across the ladder, and a ``non-topological stripe'', for which there is no
phase shift across the ladder. We perform one-loop renormalization group
calculations to determine the low energy properties. We compare the results
with those of the isolated ladder and show that for small doping
superconductivity is enhanced in the topological stripe, and suppressed in the
non-topological one. In the topological stripe, the superconducting order
parameter is a mixture of a spin singlet component with zero momentum and a
spin triplet component with momentum . We argue that this mixture is
generic, and is due to the presence of a new term in the quantum
Ginzburg-Landau action. Some consequences of this mixing are discussed.Comment: 6 pages, 3 eps figure
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