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Arts & Sciences Articles

1996

Articles 1 - 3 of 3

Full-Text Articles in Physics

Semiclassical Scattering In A Circular Semiconductor Microstructure, C. D. Schwieters, J. A. Alford, John B. Delos Oct 1996

Semiclassical Scattering In A Circular Semiconductor Microstructure, C. D. Schwieters, J. A. Alford, John B. Delos

Arts & Sciences Articles

The conductance of a microscopic junction shows fluctuations caused by quantum interference of waves that follow different paths between the leads. We give a semiclassical formula for these fluctuations. The theory utilizes trajectories which travel between the centers of the lead apertures; it also incorporates diffraction at these apertures. We extend the theory to include ‘‘ghost paths,’’ which scatter diffractively off the lead mouths. Semiclassical S-matrix elements are computed for a circular junction over a range of Fermi wave numbers, and the large-scale structure of these matrix elements shows good agreement with quantum results. Finally, we propose a hypothesis …


Slow Down, D. Chris Benner, Rodelle A. Benner Oct 1996

Slow Down, D. Chris Benner, Rodelle A. Benner

Arts & Sciences Articles

No abstract provided.


Bifurcation Of The Periodic Orbits Of Hamiltonian Systems: An Analysis Using Normal Form Theory, D. A. Sadovskii, John B. Delos Aug 1996

Bifurcation Of The Periodic Orbits Of Hamiltonian Systems: An Analysis Using Normal Form Theory, D. A. Sadovskii, John B. Delos

Arts & Sciences Articles

We develop an analytic technique to study the dynamics in the neighborhood of a periodic trajectory of a Hamiltonian system. The theory begins with Poincaré and Birkhoff; major modern contributions are due to Meyer, Arnol'd, and Deprit. The realization of the method relies on local Fourier-Taylor series expansions with numerically obtained coefficients. The procedure and machinery are presented in detail on the example of the ‘‘perpendicular’’ (z=0) periodic trajectory of the diamagnetic Kepler problem. This simple one-parameter problem well exhibits the power of our technique. Thus, we obtain a precise analytic description of bifurcations observed by J.-M. Mao …