2,039 research outputs found
Unpolarized states and hidden polarization
We capitalize on a multipolar expansion of the polarisation density matrix,
in which multipoles appear as successive moments of the Stokes variables. When
all the multipoles up to a given order vanish, we can properly say that the
state is th-order unpolarized, as it lacks of polarization information to
that order. First-order unpolarized states coincide with the corresponding
classical ones, whereas unpolarized to any order tally with the quantum notion
of fully invariant states. In between these two extreme cases, there is a rich
variety of situations that are explored here. The existence of \textit{hidden}
polarisation emerges in a natural way in this context.Comment: 7 pages, 3 eps-color figures. Submitted to PRA. Comments welcome
Multiexcitons confined within a sub-excitonic volume: Spectroscopic and dynamical signatures of neutral and charged biexcitons in ultrasmall semiconductor nanocrystals
The use of ultrafast gating techniques allows us to resolve both spectrally
and temporally the emission from short-lived neutral and negatively charged
biexcitons in ultrasmall (sub-10 nm) CdSe nanocrystals (nanocrystal quantum
dots). Because of forced overlap of electronic wave functions and reduced
dielectric screening, these states are characterized by giant interaction
energies of tens (neutral biexcitons) to hundreds (charged biexcitons) of meV.
Both types of biexcitons show extremely short lifetimes (from sub-100
picoseconds to sub-picosecond time scales) that rapidly shorten with decreasing
nanocrystal size. These ultrafast relaxation dynamics are explained in terms of
highly efficient nonradiative Auger recombination.Comment: 5 pages, 4 figures, to be published in Phys. Rev.
Real-time Chern-Simons term for hypermagnetic fields
If non-vanishing chemical potentials are assigned to chiral fermions, then a
Chern-Simons term is induced for the corresponding gauge fields. In thermal
equilibrium anomalous processes adjust the chemical potentials such that the
coefficient of the Chern-Simons term vanishes, but it has been argued that
there are non-equilibrium epochs in cosmology where this is not the case and
that, consequently, certain fermionic number densities and large-scale
(hypermagnetic) field strengths get coupled to each other. We generalise the
Chern-Simons term to a real-time situation relevant for dynamical
considerations, by deriving the anomalous Hard Thermal Loop effective action
for the hypermagnetic fields, write down the corresponding equations of motion,
and discuss some exponentially growing solutions thereof.Comment: 13 page
Taste as making of the design profession
The article describes the potentiality of phenomenon "taste" in vocational training the designerВ статье делается попытка раскрыть феномен «вкуса» в профессиональной подготовке дизайнер
Problems of quality of design-formation in professional-pedagogical system
The article describes of the analysis of quality of preparation of the designer-teacherВ статье делается попытка анализа качества подготовки дизайнера-педагог
Interpretations in education at global processes as the conflict
Authors state model development of nonclassical pedagogics in conditions of global processesВ статье сделана попытка смоделировать развитие неклассической педагогики в условиях глобализаци
Infographics as didactic design
This paper about the phenomenon of info graphics like necessary component of didactic infodesignВ статье представлен феномен инфографики как инструментальные технологии и средства дидактического инфодизайн
Aesthetics ignorance in the paradigm of design
Authors open the reasons professional ignorance in designВ статье сделана попытка раскрыть причины профессионального невежества в дизайн
Quantum polarization tomography of bright squeezed light
We reconstruct the polarization sector of a bright polarization squeezed beam
starting from a complete set of Stokes measurements. Given the symmetry that
underlies the polarization structure of quantum fields, we use the unique SU(2)
Wigner distribution to represent states. In the limit of localized and bright
states, the Wigner function can be approximated by an inverse three-dimensional
Radon transform. We compare this direct reconstruction with the results of a
maximum likelihood estimation, finding an excellent agreement.Comment: 15 pages, 5 figures. Contribution to New Journal of Physics, Focus
Issue on Quantum Tomography. Comments welcom
Pedagogical artistry in professional pedagogical paradigm
The article describes of pedagogical virtuosity as necessary component of professional skillВ статье раскрываются основы педагогического артистизма как необходимого компонента профессионального мастерств
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