4,133 research outputs found
Correlations in optically-controlled quantum emitters
We address the problem of optically controlling and quantifying the
dissipative dynamics of quantum and classical correlations in a set-up of
individual quantum emitters under external laser excitation. We show that both
types of correlations, the former measured by the quantum discord, are present
in the system's evolution even though the emitters may exhibit an early stage
disentanglement. In the absence of external laser pumping,we demonstrate
analytically, for a set of suitable initial states, that there is an entropy
bound for which quantum discord and entanglement of the emitters are always
greater than classical correlations, thus disproving an early conjecture that
classical correlations are greater than quantum correlations. Furthermore, we
show that quantum correlations can also be greater than classical correlations
when the system is driven by a laser field. For scenarios where the emitters'
quantum correlations are below their classical counterparts, an optimization of
the evolution of the quantum correlations can be carried out by appropriately
tailoring the amplitude of the laser field and the emitters' dipole-dipole
interaction. We stress the importance of using the entanglement of formation,
rather than the concurrence, as the entanglement measure, since the latter can
grow beyond the total correlations and thus give incorrect results on the
actual system's degree of entanglement.Comment: 11 pages, 10 figures, this version contains minor modifications; to
appear in Phys. Rev.
New results for hadronic collisions in the framework of the Parton-Based Gribov-Regge Theory
We recently proposed a new approach to high energy nuclear scattering, which
treats hadronic collisions in a sophisticated way. Demanding theoretical
consistency as a minimal requirement for a realistic model, we provide a
solution for the energy conservation, screening problems and identical
elementary interactions, the so-called "Parton-Based Gribov-Regge Theory"
including enhanced diagrams. We can now present some of our results for SPS and
RHIC energies.Comment: 4 pages, 3 figures, To appear in the proceedings of Quark Matter 2002
(QM 2002), Nantes, France, 18-24 Jul 200
Syöpäsolun erilainen energia-aineenvaihdunta
Tiivistelmä. Syöpäsolujen energia-aineenvaihdunta poikkeaa normaalin kasvavan solun energia-aineenvaihdunnasta useammalla eri tavalla. Syöpäsolut tehostavat glukoosin hajotusta eli glykolyysiä ja hillitsevät happea vaativaa oksidatiivista fosforylaatiota, joka on solun pääsäännöllinen energiantuotantoreitti. Syöpäsolut tuottavat laktaattidehydrogenaasin avulla pyruvaatista laktaattia sekä tuottavat hapettuneita kofaktoreita, jotta glykolyysin tehokkuus säilyisi. Glykolyysi tehostaa makromolekyylien synteesireittejä ja tuottaa hieman ATP-energiaa solujen tehokkaaseen kasvuun ja jakaantumiseen. Glukoosin hiilirungon lisäksi syöpäsolut hyödyntävät glutamiinin hiilirunkoa uusien molekyylien synteesiin. Kasvaimen laajentuessa solujen hapen- ja ravinteidensaanti kärsii. Olemassaolevien verisuoniverkostojen laajentaminen syöpäsolujen ympärille parantaa niiden elinmahdollisuuksia. Syöpäsolut tuottavat transkriptiotekijöitä, kuten c-Myc ja HIF-1, tehostamaan solujen kasvua ja selviytymistä muuttuvissa olosuhteissa. HIF-1 aktivoituu hapenpuutteessa, mutta voidaan aktivoida myös muiden tekijöiden toimesta. Syöpäsolujen aineenvaihduntareitit ovat kompleksisia, eikä kaikkien osatekijöiden roolia vielä täysin tunneta
Factores multiplicadores del río Tunjuelo
(Eng) The most important sources of pollution in urban rivers are the sewage system discharges, disturbing
the quality and behavior patterns of water resources. The Tunjuelo River is one of the most polluted and
important stream from Bogota city, receiving numerous wastewater discharges. Therefore, its sanitation
has become one of the main objectives of the environmental authority. However, in order to take action
is necessary to understand the water quality behavior specifically loads patterns. This article shows the
results of the load multiplier factors for total suspended solids (TSS) and biochemical oxygen demand
(BOD), these factors were calculated to understand the behavior of wastewater discharges and at different
points on the river. Finally, each discharge has its own characteristics that affect differently the behavior
of the river downstream, resulting in a distortion in the flow pattern in most of the sampled points.(Spa) Las fuentes puntuales de contaminación más importantes en los ríos urbanos son las descargas directas
del sistema de alcantarillado, además estas afectan la calidad y el patrón de comportamiento de las fuentes
hídricas. El río Tunjuelo es una de las corrientes de agua más importante y contaminada de la ciudad de
Bogotá, pues recibe una gran cantidad de vertimientos. Por lo anterior su saneamiento se ha convertido
en uno de los principales objetivos de la autoridad ambiental, sin embargo, para poder tomar acciones es
necesario entender su comportamiento. En el presente artículo se muestran los resultados de los factores
multiplicadores de carga para sólidos suspendidos totales (SST) y demanda bioquímica de oxígeno
(DBO), puesto que estos son el instrumento económico para el cálculo de la tasa retributiva en Colombia,
los cuales fueron calculados para entender el comportamiento de las descargas de aguas residuales y el
de diferentes puntos sobre el río. Finalmente, se puede observar que cada descarga tiene características
propias que afectan de diferente manera el comportamiento del río aguas abajo, generando como resultado
una distorsión en el patrón de flujo de los factores multiplicadores en la mayoría de puntos muestreados
An Application of Kerr Blackhole Fly-Wheel Model to Statistical Properties of QSOs/AGNs
The aim of this work is to demonstrate the properties of the magnetospheric
model around Kerr blackholes (BHs), so-called the fly-wheel (rotation driven)
model. The fly-wheel engine of the BH-accretion disk system is applied to the
statistics of QSOs/AGNs. In the model, the central BH is assumed to be formed
at and obtains nearly maximum but finite rotation energy (
extreme Kerr BH) at the formation stage. The inherently obtained rotation
energy of the Kerr BH is released through an magnetohydrodynamic process. This
model naturally leads finite lifetime of AGN activity.
Nitta et al. (1991) clarified individual evolution of Kerr BH fly-wheel
engine which is parametrized by BH mass, initial Kerr parameter, magnetic field
near the horizon and a dimension-less small parameter. We impose a statistical
model for the initial mass function (IMF) of ensemble of BHs by the
Press-Schechter formalism. By the help of additional assumptions, we can
discuss the evolution of the luminosity function and the spatial number density
of QSOs/AGNs.Comment: 12 pages, 7 figures Fig.7 has been replace
A study of random laser modes in disordered photonic crystals
We studied lasing modes in a disordered photonic crystal. The scaling of the
lasing threshold with the system size depends on the strength of disorder. For
sufficiently large size, the minimum of the lasing threshold occurs at some
finite value of disorder strength. The highest random cavity quality factor was
comparable to that of an intentionally introduced single defect. At the
minimum, the lasing threshold showed a super-exponential decrease with the size
of the system. We explain it through a migration of the lasing mode frequencies
toward the photonic bandgap center, where the localization length takes the
minimum value. Random lasers with exponentially low thresholds are predicted.Comment: 4 pages, 4 figure
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