196,188 research outputs found
Resonance Energy Transfer
Resonance energy transfer, also known as Förster- or fluorescence- resonance energy transfer, or electronic energy transfer, is a photonic process whose relevance in many major areas of science is reflected both by a wide prevalence of the effect and through numerous technical applications. The process, operating through an optical near-field mechanism, effects a transport of electronic excitation between physically distinct atomic or molecular components, based on transition dipole-dipole coupling. In this chapter a comprehensive survey of the process is presented, beginning with an outline of the history and highlighting the early contributions of Perrin and Förster. A review of the photophysics behind resonance energy transfer follows, and then a discussion of some prominent applications of resonance energy transfer. Particular emphasis is given to analysis and sensing techniques used in molecular biology, ranging from the ‘spectroscopic ruler’ measurements of functional group separation, to fluorescence lifetime microscopy. The chapter ends with a description of the role of energy transfer in photosynthetic light harvesting
A probability current analysis of energy transport in open quantum systems
We introduce a probability current analysis of excitation energy transfer
between states of an open quantum system. Expressing the energy transfer
through currents of excitation probability between the states in a site
representation enables us to gain key insights into the energy transfer
dynamics. It allows to, i) identify the pathways of energy transport in large
networks of sites and to quantify their relative weights, ii) quantify the
respective contributions of unitary dynamics, dephasing, and
relaxation/dissipation processes to the energy transfer, and iii) quantify the
contribution of coherence to the energy transfer. Our analysis is general and
can be applied to a broad range of open quantum system descriptions (with
coupling to non-Markovian environments) in a straightforward manner
Cosmological model with energy transfer
The observations of SNIa suggest that we live in the acceleration epoch when
the densities of the cosmological constant term and matter are almost equal.
This leads to the cosmic coincidence conundrum. As the explanation for this
problem we propose the FRW model with dark matter and dark energy which
interact each other exchanging energy. We show that the cubic correction to the
Hubble law, measured by distant supernovae type Ia, probes this interaction. We
demonstrate that influences between nonrelativistic matter and vacuum sectors
are controlled by third and higher derivatives of the scale factor. As an
example we consider flat decaying FRW cosmologies. We point out
the possibility of measure of the energy transfer by the cubic and higher
corrections to Hubble's law. The statistical analysis of SNIa data is used as
an evidence of energy transfer. We find that there were the transfer from the
dark energy sector to the dark matter one without any assumption about physics
governing this process. We confront this hypothesis about the transfer with
SNIa observations and find that the transfer the phantom and matter sector is
admissible for . We also demonstrate that it is
possible to differentiate between the energy transfer model and the variable
coefficient equation of state model.Comment: RevTeX4, 8 pages, 4 figure; new section on testing the transfer from
SNI
Engineering directed excitonic energy transfer
We provide an intuitive platform for engineering exciton transfer dynamics.
We show that careful consideration of the spectral density, which describes the
system-bath interaction, leads to opportunities to engineer the transfer of an
exciton. Since excitons in nanostructures are proposed for use in quantum
information processing and artificial photosynthetic designs, our approach
paves the way for engineering a wide range of desired exciton dynamics. We
carefully describe the validity of the model and use experimentally relevant
material parameters to show counter-intuitive examples of a directed exciton
transfer in a linear chain of quantum dots
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