121 research outputs found
Green Function Monte Carlo Method for Excited States of Quantum System
A novel scheme to solve the quantum eigenvalue problem through the
imaginary-time Green function Monte Carlo method is presented. This method is
applicable to the excited states as well as to the ground state of a generic
system. We demonstrate the validity of the method with the numerical examples
on three simple systems including a discretized sine-Gordon model.Comment: RevTeX 5pg with 3 epsf figure
Threshold resonance and controlled filtering in quantum star graphs
We design two simple quantum devices applicable as an adjustable quantum
spectral filter and as a flux controller. Their function is based upon the
threshold resonance in a F\"ul\"op-Tsutsui type star graph with an external
potential added on one of the lines. Adjustment of the potential strength
directly controls the quantum flow from the input to the output line. This is
the first example to date in which the quantum flow control is achieved by
addition of an external field not on the channel itself, but on other lines
connected to the channel at a vertex.Comment: ReVTeX format, 4 pages, 6 figure
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