Hydrogenic Rydberg atoms in strong magnetic fields: Theoretical and experimental spectra in the transition region from regularity to irregularity

Si:P as a laboratory analogue for hydrogen on high magnetic field white dwarf stars

Laboratory spectroscopy of atomic hydrogen in a magnetic flux density of 10(5) T (1 gigagauss), the maximum observed on high-field magnetic white dwarfs, is impossible because practically available fields are about a thousand times less. In this regime, the cyclotron and binding energies become equal. Here we demonstrate Lyman series spectra for phosphorus impurities in silicon up to the equivalent field, which is scaled to 32.8 T by the effective mass and dielectric constant. The spectra reproduce the high-field theory for free hydrogen, with quadratic Zeeman splitting and strong mixing of spherical harmonics. They show the way for experiments on He and H(2) analogues, and for investigation of He(2), a bound molecule predicted under extreme field conditions.

Chaotic scattering, unstable periodic orbits, and fluctuations in quantum transport

The field of quantum chaos has recently focused attention on the quantum description of chaotic scattering processes. The new physical intuition, analytical methods, and numerical tools developed in the study of the quantum behavior of classically chaotic bound systems, like quantum billiards or atoms in strong fields, has led to exciting new predictions for the scattering of electromagnetic waves in curved waveguides, electrons in mesoscopic wires, and atoms off molecules. After a brief review of recent progress in the field of quantum chaos, this paper focuses on specific results relating to ballistic electron transport in small, mesoscopic devices. Several specific geometries are suggested for experimental studies of this "game" of quantum pinball with explicit predictions for the fluctuations in the electrical conductivity as functions of the electron Fermi energy and of an applied magnetic field.