Quantum handshake between photons and single molecules.
Physical processes in the nanoscale are often governed by rules of quantum mechanics. To study these quantum processes or transfer them between distant systems, photons are possibly the most promising More info
and most credible candidates because they interact weekly with matter and it is possible to send them over long distances through optical fibers or free space. For addressing the microscopic quantum processes with photons, the interaction between light and the nanoscale system has to be optimized and also faithfully transfer the quantum information. In technical terms, the interaction should preserve quantum coherence.
Sanli Faez and his collaborators at the Max-Planck institute in Erlangen, Germany, have built a new platform for coherent interaction between photons and single molecules. Their system consists of an ensemble of organic dye molecules that are embedded inside the tight optical mode of a waveguide made of another organic material inside a glass capillary. With a careful choice of materials and the fabrication process, each dye molecule acts similar to a perfect quantum two-level system with a very high degree of coherence. They have measured the transmission of photons through this waveguide, which is readily coupled to an optical fiber, and have seen that each time the frequency of the laser matches the narrow optical transition of the molecules there is a dip of a few percent. Because the interaction between each molecule and light is elastic the quantum coherence is preserved. Their article will soon appear in Physical Review Letters.
The special advantage of this platform, over other schemes of enhance light-matter interaction such as cavities, is the possibility of coupling several dye molecules to the same mode of light. Meanwhile, the frequency of each molecule can be externally tuned. These two possibilities, together, allow for studying many-body quantum interactions in a controlled fashion. Furthermore, the small dye molecules can be used as local quantum reporters for other quantum processes in their local environment, for example tunneling of electrons.
Publ. 23-10-2014 20:05
Topology and dynamics of active nematic vesicles.
Engineering synthetic materials that mimic the remarkable complexity of living organisms is a fundamental challenge in science and technology. We studied the spatiotemporal patterns that emerge when an active nematic More info
film of microtubules and molecular motors is encapsulated within a shape-changing lipid vesicle. Unlike in equilibrium systems, where defects are largely static structures, in active nematics defects move spontaneously and can be described as self-propelled particles. The combination of activity, topological constraints, and vesicle deformability produces a myriad of dynamical states. We highlight two dynamical modes: a tunable periodic state that oscillates between two defect configurations, and shape-changing vesicles with streaming filopodia-like protrusions. These results demonstrate how biomimetic materials can be obtained when topological constraints are used to control the non-equilibrium dynamics of active matter.
Keber FC, Loiseau E, Sanchez T, DeCamp SJ, Giomi L, Bowick MJ, Marchetti MC, Dogic Z, Bausch AR. Science (2014) 345:1135-9.
Sachse R, Dondapati SK, Fenz SF, Schmidt T & Kubick S. (2014) Membrane protein synthesis in cell-free systems: From bio-mimetic systems to bio-membranes., FEBS Lett., 588, 2774-81. [Abstract][DOI][pdf]
Armando Hernandez-Garcia, Daniela J. Kraft, Anne F.J. Janssen, Paul H. H. Bomans, Nico A.J.M. Sommerdijk, Dominique M.E. Thies-Weesie, Marco E. Favretto, Roland Brock, Frits A. de Wolf, Marc W. T. Werten, Paul van der Schoot, Martien Cohen Stuart & Renko de Vries (2014) Design and self-assembly of simple coat proteins for artificial viruses, Nature Nanotechnology, 8, 9, 698–702. [DOI]