11,140 research outputs found
Landau Ghosts and Anti-Ghosts in Condensed Matter and High Density Hadronic Matter
It is observed that the ``ghost'' (originally discovered by Landau in quantum
electro-dynamics) and its counterparts in other theories are indeed ubiquitous
as they occur in a one-loop approximation to any conventional (unbroken) gauge
theory. The mechanism is first exposed in its generality via the Dyson equation
and a simple but explicit example in condensed matter is provided through the
static Clausius-Mossotti and its dynamic counterpart the Lorenz-Lorentz
equation. The physical phase transition phenomenon associated with it is found
to be super-radiance. We verify quantitatively that water (and many other polar
liquids) are indeed super-radiant at room temperature. In quantum
chromo-dynamics on the other hand, we encounter, thanks to asymptotic freedom,
an ``anti-ghost'' which is closely associated with color confinement. Thus, in
QCD, free quarks and glue exist in a super-radiant phase and hadronic matter in
the normal one.Comment: LaTeX 12 Pages and 2 *.eps Figure
Curvature Inspired Cosmological Scenario
Using modified gravity with non-linear terms of curvature, and (with being the positive real number and being the scalar
curvature), cosmological scenario,beginning at the Planck scale, is obtained.
Here, a unified picture of cosmology is obtained from gravity. In this
scenario, universe begins with power-law inflation, followed by deceleration
and acceleration in the late universe as well as possible collapse of the
universe in future. It is different from dark energy models with
non-linear curvature terms assumed as dark energy. Here, dark energy terms are
induced by linear as well as non-linear terms of curvature in Friedmann
equation being derived from modified gravity.It is also interesting to see
that, in this model, dark radiation and dark matter terms emerge spontaneously
from the gravitational sector. It is found that dark energy, obtained here,
behaves as quintessence in the early universe and phantom in the late universe.
Moreover, analogous to brane-tension in brane-gravity inspired Friedmann
equation, a tension term arises here being called as cosmic tension.
It is found that, in the late universe, Friedmann equation (obtained here)
contains a term ( being the phantom energy density)
analogous to a similar term in Friedmann equation with loop quantum effects, if
and brane-gravity correction when Comment: 19 Pages. To appear in Int. J. Thro. Phy
Resonance Damping in Ferromagnets and Ferroelectrics
The phenomenological equations of motion for the relaxation of ordered phases
of magnetized and polarized crystal phases can be developed in close analogy
with one another. For the case of magnetized systems, the driving magnetic
field intensity toward relaxation was developed by Gilbert. For the case of
polarized systems, the driving electric field intensity toward relaxation was
developed by Khalatnikov. The transport times for relaxation into thermal
equilibrium can be attributed to viscous sound wave damping via
magnetostriction for the magnetic case and electrostriction for the
polarization case.Comment: 5 pages no figures ReVTeX
Light from Cascading Partons in Relativistic Heavy-Ion Collisions
We calculate the production of high energy photons from Compton and
annihilation processes as well as fragmentation off quarks in the parton
cascade model. The multiple scattering of partons is seen to lead to a
substantial production of high energy photons, which rises further when parton
multiplication due to final state radiation is included. The photon yield is
found to be proportional to the number of collisions among the cascading
partons.Comment: revised version: 4 pages, 4 figures, uses REVTEX
Fludarabine and cyclophosphamide based reduced intensity conditioning (RIC) regimens reduce rejection and improve outcome in Indian patients undergoing allogeneic stem cell transplantation for severe aplastic anemia
Thirty-five patients (25 men and 10 women) with a median age of 20 years with severe aplastic anaemia (SAA) underwent HLA identical stem cell transplantation (HSCT) using a combination of fludarabine and cyclophosphamideanti-thymocyte globulin between 2004 and 2006. Cyclosporine and mini methotrexate were used as GVHD prophylaxis. Graft source included peripheral blood stem cells (28) or G-CSF stimulated bone marrow (7). Two patients expired <7 days post-HSCT while 32 (91.5%) patients engrafted with a median neutrophil and platelet engraftment time of 12 days each. Three patients (8.5%) developed veno-occlusive disease while acute GVHD occurred in 29% of evaluable patients, with chronic GVHD in 32%. At a mean follow-up of 22 months, 29 (82.8%) are alive and well. When compared with 26 patients previously transplanted using Cy200/antilymphocyte globulin, there was faster neutrophil engraftment (12 vs 16 days; P=0.002) with significantly lower rejection rates (2.9 vs 30.7%; P=0.003) and a superior event-free (82.8 vs 38.4%; P=0.001) and overall survival (82.8 vs 46.1%; P=0.005). A combination of fludarabine with cyclophosphamideanti-thymocyte globulin reduces rejection and improves overall and event-free survival in Indian patients undergoing HSCT for severe aplastic anaemia
Green's function for a Schroedinger operator and some related summation formulas
Summation formulas are obtained for products of associated Lagurre
polynomials by means of the Green's function K for the Hamiltonian H =
-{d^2\over dx^2} + x^2 + Ax^{-2}, A > 0. K is constructed by an application of
a Mercer type theorem that arises in connection with integral equations. The
new approach introduced in this paper may be useful for the construction of
wider classes of generating function.Comment: 14 page
Empirical determination of charm quark energy loss and its consequences for azimuthal anisotropy
We propose an empirical model to determine the form of energy loss of charm
quarks due to multiple scatterings in quark gluon plasma by demanding a good
description of production of D mesons and non-photonic electrons in
relativistic collision of heavy nuclei at RHIC and LHC energies. Best results
are obtained when we approximate the momentum loss per collision , where is a constant depending on the
centrality and the centre of mass energy. Comparing our results with those
obtained earlier for drag coefficients estimated using Langevin equation for
heavy quarks we find that up to half of the energy loss of charm quarks at top
RHIC energy could be due to collisions while that at LHC energy at 2760 GeV/A
the collisional energy loss could be about one third of the total. Estimates
are obtained for azimuthal anisotropy in momentum spectra of heavy mesons, due
to this energy loss. We further suggest that energy loss of charm quarks may
lead to an enhanced production of D-mesons and single electrons at low in
AA collisions.Comment: 11 pages, 3 figures, Typographical errors corrected, Key-words and
PACS indices added, sequence of figures corrected, references added in
section 3, discussions expande
Molecular remission with arsenic trioxide in patients with newly diagnosed acute promyelocytic leukemia
Thirty six APML patients achieving hematological remission with As2O3 were serially monitored using RT-PCR. Though only 5.5% achieved molecular remission at induction remission, 94.5% became negative during consolidation. At 20 months follow-up, 85% remain in remission but longer follow up studies are needed to monitor late relapses
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