8,207 research outputs found
Extraordinary exciton conductance induced by strong coupling
We demonstrate that exciton conductance in organic materials can be enhanced
by several orders of magnitude when the molecules are strongly coupled to an
electromagnetic mode. Using a 1D model system, we show how the formation of a
collective polaritonic mode allows excitons to bypass the disordered array of
molecules and jump directly from one end of the structure to the other. This
finding could have important implications in the fields of exciton transistors,
heat transport, photosynthesis, and biological systems in which exciton
transport plays a key role.Comment: Main text: 5 pages, 4 figures; Supplemental: 2 pages, 1 figure.
Version 2: Updated reference to related work arXiv:1409.2550. Version 3:
Updated to version accepted for publication in Physical Review Letter
Cavity-induced modifications of molecular structure in the strong coupling regime
In most theoretical descriptions of collective strong coupling of organic
molecules to a cavity mode, the molecules are modeled as simple two-level
systems. This picture fails to describe the rich structure provided by their
internal rovibrational (nuclear) degrees of freedom. We investigate a
first-principles model that fully takes into account both electronic and
nuclear degrees of freedom, allowing an exploration of the phenomenon of strong
coupling from an entirely new perspective. First, we demonstrate the
limitations of applicability of the Born-Oppenheimer approximation in strongly
coupled molecule-cavity structures. For the case of two molecules, we also show
how dark states, which within the two-level picture are effectively decoupled
from the cavity, are indeed affected by the formation of collective strong
coupling. Finally, we discuss ground-state modifications in the ultra-strong
coupling regime and show that some molecular observables are affected by the
collective coupling strength, while others only depend on the single-molecule
coupling constant.Comment: 12 pages, 8 figure
Seqüenciació de nova generació i salut en el segle XXI
En la primera dècada del segle XXI l'aparició de les plataformes de seqüenciació massiva de nova generació (NGS) ha produït una autèntica revolució en la seqüenciació del DNA. Aquesta tecnologia permet seqüenciar en paral·lel milions de molècules de DNA a un preu molt inferior al de la seqüenciació tradicional i s'està traslladant ràpidament des del terreny de la investigació bàsica a l'assistència de capçalera al pacient. El seu extraordinari potencial
en diferents especialitats mèdiques afectarà pràcticament tots els aspectes de l'atenció
clínica, ja que permetrà fer rutinàriament proves diagnòstiques fins ara inconcebibles. En els propers deu anys probablement apareixeran noves plataformes de NGS per a ús clínic, encara més versàtils, precises, assequibles i fins i tot portàtils, que permetran plantejar la seqüenciació del genoma complet com a mètode universal de diagnòstic genètic. Tot això, unit a la millora del coneixement per predir com una variació genètica afecta la susceptibilitat a la malaltia, l'evolució d'aquesta o la resposta al tractament mèdic, sens dubte tindrà un efecte transformador en l'ús i protagonisme de la informació genètica en la rutina clínica del segle XXI.In the first decade of the 21st century the emergence of massive Next Generation Sequencing (NGS) platforms has produced a revolution in DNA sequencing. This technology allows parallel sequencing of millions of DNA molecules at a much lower price than traditional sequencing and it is rapidly moving from the field of basic research to routinely use in clinical practice. Its tremendous potential in several medical specialties will affect
virtually all aspects of clinical care, as it will routinely perform diagnostic tests so far
inconceivable. In the next ten years probably new NGS platforms for clinical use will appear
more versatile, accurate, affordable and even portable that will enable sequencing the
whole genome as a universal method of genetic diagnosis. This issue, together with the improved
knowledge to predict how genetic variation affects the disease susceptibility, the evolution of illness or the response to medical treatment, will certainly have a transformative effect on the usage and significance of genetic information in the clinical routine of the 21st century
Symbolic analysis tools-the state of the art
This paper reviews the main last generation symbolic analyzers, comparing them in terms of functionality, pointing out also their shortcomings. The state of the art in this field is also studied, pointing out directions for future research
Latino Cultural Center in Chicago
As Latino immigrant families assimilate in to U.S. Society there is the risk that future generations will not learn about their history, culture and traditions. Many Latin people born in the United States do not learn about their heritage, they just adapt to the American lifestyle. There is a need for new infrastructure that works as cultural exchange and support for this community. This Cultural Center is intended to be part of the existing downtown cultural infrastructure. The idea is to include it as part of the cultural and educational organizations in order to integrate it with tourism
Farm Cooperatives and the Social Economy: The Case of Spain
The term “Social Economy†is used to mean a set of organizations that share specific operational features, such as solidarity, mutual assistance, open membership, democratic management and people-based decision-making and distribution of surpluses, which depend on the activity carried out by each person irrespective of the capital invested. Farm cooperatives undoubtedly belong to this group. In recent years, Spanish farm cooperatives have been experiencing substantial business development. This process is a consequence of the latest changes in the regulations governing Spanish cooperatives. Major cooperative groups with high turnovers have developed in this positive environment. Although there are differences between countries, the European cooperative movement is a good example of the prominence that cooperatives have achieved in many sectors. Their traditional goals are changing and one of their current priorities is to meet the requirements of the CAP (Common Agricultural Policy) as regards agricultural multi-functionality. Nevertheless, the principles of this concept were already present in their own tenets. This paper aims to show the role of the cooperatives in the new social requirements, taking into account their functioning principles and the new conceptual frame they are involved in.Agribusiness,
Quantum theory of collective strong coupling of molecular vibrations with a microcavity mode
We develop a quantum mechanical formalism to treat the strong coupling
between an electromagnetic mode and a vibrational excitation of an ensemble of
organic molecules. By employing a Bloch-Redfield-Wangsness approach, we show
that the influence of dephasing-type interactions, i.e., elastic collisions
with a background bath of phonons, critically depends on the nature of the bath
modes. In particular, for long-range phonons corresponding to a common bath,
the dynamics of the "bright state" (the collective superposition of molecular
vibrations coupling to the cavity mode) is effectively decoupled from other
system eigenstates. For the case of independent baths (or short-range phonons),
incoherent energy transfer occurs between the bright state and the uncoupled
dark states. However, these processes are suppressed when the Rabi splitting is
larger than the frequency range of the bath modes, as achieved in a recent
experiment [Shalabney et al., Nat. Commun. 6, 5981 (2015)]. In both cases, the
dynamics can thus be described through a single collective oscillator coupled
to a photonic mode, making this system an ideal candidate to explore cavity
optomechanics at room temperature.Comment: 13 pages, 4 figure
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