16,711 research outputs found
Optical bistability in sideband output modes induced by squeezed vacuum
We consider two-level atoms in a ring cavity interacting with a broadband
squeezed vacuum centered at frequency and an input monochromatic
driving field at frequency . We show that, besides the central mode
(at \o), many other {\em sideband modes} are produced at the output, with
frequencies shifted from by multiples of .
Here we analyze the optical bistability of the two nearest sideband modes, one
red-shifted and the other blue-shifted.Comment: Replaced with final published versio
Primary breast sarcoma: case report
Primary breast sarcoma is a rare entity occurring in 0.5% of women with breast malignancy. Like in breast carcinoma, delay in its diagnosis has important clinical and treatment implications. The subject of this report presented at our breast unit with advanced breast lesion months after she noticed a small lump in her right breast. She had no clear diagnosis despite several consultations, in-patient treatments at two facilities in the city, breast ultrasonography, breast mammography and three fine needle aspiration cytology (FNAC) examinations. The patient needed multiple blood transfusions. A final FNAC showed ductal carcinoma. Histology following wide excision confirmed high-grade primary stromal breast sarcoma. She required adjuvant combination chemotherapy. A combination of diagnostic failures and patient fault caused delay in subject's treatment. Lesion progression during delay which influenced the pattern of physical morbidity, tumour prognosis and need for adjuvant treatment. Embracing the concept of breast care in dedicated breast units may minimise such treatment delays.
East African Medical Journal Vol.81(7) 2004: 375-37
Tight lower bound to the geometric measure of quantum discord
Dakic, Vedral and Brukner [Physical Review Letters \tf{105},190502 (2010)]
gave a geometric measure of quantum discord in a bipartite quantum state as the
distance of the state from the closest classical quantum (or zero discord)
state and derived an explicit formula for a two qubit state. Further, S.Luo and
S.Fu [Physical Review A \tf{82}, 034302 (2010)] obtained a generic form of this
geometric measure for a general bipartite state and established a lower bound.
In this brief report we obtain a rigorous lower bound to the geometric measure
of quantum discord in a general bipartite state which dominates that obtained
by S.Luo and S.Fu.Comment: 10 pages,2 figures. In the previous versions, a constraint was
ignored while optimizing the second term in Eq.(5), in which case, only a
lower bound on the geometric discord can be obtained. The title is also
consequently changed. Accepted in Phys.Rev.
Emergence of fractal behavior in condensation-driven aggregation
We investigate a model in which an ensemble of chemically identical Brownian
particles are continuously growing by condensation and at the same time undergo
irreversible aggregation whenever two particles come into contact upon
collision. We solved the model exactly by using scaling theory for the case
whereby a particle, say of size , grows by an amount over the
time it takes to collide with another particle of any size. It is shown that
the particle size spectra of such system exhibit transition to dynamic scaling
accompanied by the emergence of fractal of
dimension . One of the remarkable feature of this
model is that it is governed by a non-trivial conservation law, namely, the
moment of is time invariant regardless of the choice of the
initial conditions. The reason why it remains conserved is explained by using a
simple dimensional analysis. We show that the scaling exponents and
are locked with the fractal dimension via a generalized scaling relation
.Comment: 8 pages, 6 figures, to appear in Phys. Rev.
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