24,536 research outputs found
Evaporative Deposition in Receding Drops
We present a framework for calculating the surface density profile of a stain
deposited by a drop with a receding contact line. Unlike a pinned drop, a
receding drop pushes fluid towards its interior, continuously deposits mass
across its substrate as it evaporates, and does not produce the usual "coffee
ring." For a thin, circular drop with a constant evaporation rate, we find the
surface density of the stain goes as , where is the radius from the
drop center and is the initial outer radius. Under these conditions, the
deposited stain has a mountain-like morphology. Our framework can easily be
extended to investigate new stain morphologies left by drying drops.Comment: 6 pages, 4 figure
Anomalies and Invertible Field Theories
We give a modern geometric viewpoint on anomalies in quantum field theory and
illustrate it in a 1-dimensional theory: supersymmetric quantum mechanics. This
is background for the resolution of worldsheet anomalies in orientifold
superstring theory.Comment: 21 pages, based talk at String-Math 2013; small corrections in v
Supersolutions
We develop classical globally supersymmetric theories. As much as possible,
we treat various dimensions and various amounts of supersymmetry in a uniform
manner. We discuss theories both in components and in superspace. Throughout we
emphasize geometric aspects. The beginning chapters give a general discussion
about supersymmetric field theories; then we move on to detailed computations
of lagrangians, etc. in specific theories. An appendix details our sign
conventions. This text will appear in a two-volume work "Quantum Fields and
Strings: A Course for Mathematicians" to be published soon by the American
Mathematical Society. Some of the cross-references may be found at
http://www.math.ias.edu/~drm/QFT/Comment: 130 pages, AMSTe
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