2,376 research outputs found
Prostate-specific antigen, Gleason sum and clinical T stage for predicting the need for radionuclide bone scan for prostate cancer patients in Japan
The definitive version is available at www.blackwell-synergy.com.ArticleINTERNATIONAL JOURNAL OF UROLOGY. 12(8): 728-732 (2005)journal articl
Critical exponents of a multicomponent anisotropic t-J model in one dimension
A recently presented anisotropic generalization of the multicomponent
supersymmetric model in one dimension is investigated. This model of
fermions with general spin- is solved by Bethe ansatz for the ground state
and the low-lying excitations. Due to the anisotropy of the interaction the
model possesses massive modes and one single gapless excitation. The
physical properties indicate the existence of Cooper-type multiplets of
fermions with finite binding energy. The critical behaviour is described by a
conformal field theory with continuously varying exponents depending on
the particle density. There are two distinct regimes of the phase diagram with
dominating density-density and multiplet-multiplet correlations, respectively.
The effective mass of the charge carriers is calculated. In comparison to the
limit of isotropic interactions the mass is strongly enhanced in general.Comment: 10 pages, 3 Postscript figures appended as uuencoded compressed
tar-file to appear in Z. Phys. B, preprint Cologne-94-474
Magnetoelastic mechanism of spin-reorientation transitions at step-edges
The symmetry-induced magnetic anisotropy due to monoatomic steps at strained
Ni films is determined using results of first - principles relativistic
full-potential linearized augmented plane wave (FLAPW) calculations and an
analogy with the N\'eel model. We show that there is a magnetoelastic
anisotropy contribution to the uniaxial magnetic anisotropy energy in the
vicinal plane of a stepped surface. In addition to the known spin-direction
reorientation transition at a flat Ni/Cu(001) surface, we propose a
spin-direction reorientation transition in the vicinal plane for a stepped
Ni/Cu surface due to the magnetoelastic anisotropy. We show that with an
increase of Ni film thickness, the magnetization in the vicinal plane turns
perpendicular to the step edge at a critical thickness calculated to be in the
range of 16-24 Ni layers for the Ni/Cu(1,1,13) stepped surface.Comment: Accepted for publication in Phys. Rev.
Invariant Form of Hyperfine Interaction with Multipolar Moments - Observation of Octupolar Moments in NpO and CeB by NMR -
The invariant form of the hyperfine interaction between multipolar moments
and the nuclear spin is derived, and applied to discuss possibilities to
identify the antiferro-octupolar (AFO) moments by NMR experiments. The ordered
phase of NpO and the phase IV of CeLaB are studied in
detail. Recent O NMR for polycrystalline samples of NpO are
discussed theoretically from our formulation. The observed feature of the
splitting of O NMR spectrum into a sharp line and a broad line, their
intensity ratio, and the magnetic field dependence of the shift and of the
width can be consistently explained on the basis of the triple \bq AFO
ordering model proposed by Paix\~{a}o {\it et. al.} Thus, the present theory
shows that the O NMR spectrum gives a strong support to the model. The 4
O sites in the fcc NpO become inequivalent due to the secondary triple
\bq ordering of AF-quadrupoles: one cubic and three non-cubic sites. It turns
out that the hyperfine field due to the antiferro-dipole and AFO moments
induced by the magnetic field, and the quadrupolar field at non-cubic sites are
key ingredients to understand the observed spectrum. The controversial problem
of the nature of phase IV in CeLaB is also studied. It is
pointed out that there is a unique feature in the NMR spectra, if the
() AFO ordering is
realized in CeLaB. Namely, the hyperfine splitting of a B
atom pair on the sites crosses zero on the
plane when the magnetic field is rotated around the axis.Comment: 22 pages, 2 figure
Tension Dynamics and Linear Viscoelastic Behavior of a Single Semiflexible Polymer Chain
We study the dynamical response of a single semiflexible polymer chain based
on the theory developed by Hallatschek et al. for the wormlike-chain model. The
linear viscoelastic response under oscillatory forces acting at the two chain
ends is derived analytically as a function of the oscillation frequency . We
shall show that the real part of the complex compliance in the low frequency
limit is consistent with the static result of Marko and Siggia whereas the
imaginary part exhibits the power-law dependence +1/2. On the other hand, these
compliances decrease as the power law -7/8 for the high frequency limit. These
are different from those of the Rouse dynamics. A scaling argument is developed
to understand these novel results.Comment: 23 pages, 6 figure
Scaling Exponents in the Incommensurate Phase of the Sine-Gordon and U(1) Thirring Models
In this paper we study the critical exponents of the quantum sine-Gordon and
U(1) Thirring models in the incommensurate phase. This phase appears when the
chemical potential exceeds a critical value and is characterized by a
finite density of solitons. The low-energy sector of this phase is critical and
is described by the Gaussian model (Tomonaga-Luttinger liquid) with the
compactification radius dependent on the soliton density and the sine-Gordon
model coupling constant .
For a fixed value of , we find that the Luttinger parameter is
equal to 1/2 at the commensurate-incommensurate transition point and approaches
the asymptotic value away from it. We describe a possible phase
diagram of the model consisting of an array of weakly coupled chains. The
possible phases are Fermi liquid, Spin Density Wave, Spin-Peierls and Wigner
crystal.Comment: 10pages; Improved version; Submitted to Physical Review
Ultrafast carrier relaxation in GaN, In_(0.05)Ga_(0.95)N and an In_(0.05)Ga_(0.95)/In_(0.15)Ga_(0.85)N Multiple Quantum Well
Room temperature, wavelength non-degenerate ultrafast pump/probe measurements
were performed on GaN and InGaN epilayers and an InGaN multiple quantum well
structure. Carrier relaxation dynamics were investigated as a function of
excitation wavelength and intensity. Spectrally-resolved sub-picosecond
relaxation due to carrier redistribution and QW capture was found to depend
sensitively on the wavelength of pump excitation. Moreover, for pump
intensities above a threshold of 100 microJ/cm2, all samples demonstrated an
additional emission feature arising from stimulated emission (SE). SE is
evidenced as accelerated relaxation (< 10 ps) in the pump-probe data,
fundamentally altering the re-distribution of carriers. Once SE and carrier
redistribution is completed, a slower relaxation of up to 1 ns for GaN and
InGaN epilayers, and 660 ps for the MQW sample, indicates carrier recombination
through spontaneous emission.Comment: submitted to Phys. Rev.
Effect of the Three-Site Hopping Term on the t-J Model
We have used exact diagonalization and quantum Monte Carlo methods to study
the one-dimensional {t-J} model including the three-site hopping term derived
from the strong coupling limit of the Hubbard model. The three-site term may be
important to superconducting correlations since it allows direct hopping of
local singlet electron pairs. The phase diagram is determined for several
values of the strength of the three-site term and compared with that of the
{t-J} and Hubbard models. Phase separation, which exists in the t-J model is
suppressed. In the low electron density region the formation of local singlet
electron pairs is enhanced, leading to stronger superconducting correlations
even for values . A large spin gap region extends from low electron
densities up to high densities. In the low hole density region the
superconducting correlations are suppressed at in spite of enhanced
pair formation. This is because the three-site term, while enhancing the
formation of electron pairs, leads to a repulsion between holes.Comment: 9 pages including 9 figures and 1 Table. Self-unpacking postscript.
Unpacking instructions are at the beginning of the file. Submitted to
Physical Review
Exact Critical Properties of the Multi-Component Interacting Fermion Model with Boundaries
Exact critical properties of the one-dimensional SU() interacting fermion
model with open boundaries are studied by using the Bethe ansatz method. We
derive the surface critical exponents of various correlation functions using
boundary conformal field theory. They are classified into two types, i.e. the
exponents for the chiral SU() Tomonaga-Luttinger liquid and those related to
the orthogonality catastrophe. We discuss a possible application of the results
to the photoemission (absorption) in the edge state of the fractional quantum
Hall effect.Comment: 17 pages, RevTe
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