16,929 research outputs found
The interaction of thin-film flow, bacterial swarming and cell differentiation in colonies of Serratia liquefaciens
The rate of expansion of bacterial colonies of S. liquefaciens is investigated in terms of a mathematical model that combines biological as well as hydrodynamic processes. The relative importance of cell differentiation and production of an extracellular wetting agent to bacterial swarming is explored using a continuum representation. The model incorporates aspects of thin film flow with variable suspension viscosity, wetting, and cell differentiation. Experimental evidence suggests that the bacterial colony is highly sensitive to its environment and that a variety of mechanisms are exploited in order to proliferate on a variety of surfaces. It is found that a combination of effects are required to reproduce the variation of bacterial colony motility over a large range of nutrient availability and medium hardness
A trajectory-based understanding of quantum interference
Interference is one of the most fundamental features which characterizes
quantum systems. Here we provide an exhaustive analysis of the interfere
dynamics associated with wave-packet superpositions from both the standard
quantum-mechanical perspective and the Bohmian one.
From this analysis, clear and insightful pictures of the physics involved in
this kind of processes are obtained, which are of general validity (i.e.,
regardless of the type of wave packets considered) in the understanding of more
complex cases where interference is crucial (e.g., scattering problems, slit
diffraction, quantum control scenarios or, even, multipartite interactions). In
particular, we show how problems involving wave-packet interference can be
mapped onto problems of wave packets scattered off potential barriers.Comment: 27 pages, 12 figures (shortened version
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