On November 14, 2014, Prof. Dr. Phil. Bucksbaum from Stanford University paid a visit to SIOM and gave the invited presentation at Qinghe Seminar at SIOM. Prof. Ya Cheng presided over his seminar.

Prof. Bucksbaum delivered a presentation entitled by “Ultrafast Quantum Control of Electrons, Atoms, and Molecules”. In his talk, he introduced that the time scale for internal motion in atoms and small molecules was determined by their Angstrom sizes and Rydberg binding energies to be femtoseconds or shorter. The binding fields for the outermost electrons are tens of volts per Angstrom, while inner electrons can be bound by kilovolts or more, with motion measured in attoseconds. He described recent experiments and new concepts designed to help us to understand the interaction of electrons, atoms and molecules utilizing laser fields on these scales of time, photon energy and field strength. Two kinds of laser sources are employed: Strong focused infrared lasers create these extreme conditions within a single optical cycle, and thereby induce atomic phenomena that evolve during fractions of a femtosecond. This is the regime of high harmonic generation and above-threshold ionization. X-ray free electron lasers can also produce these extreme fields, but at much higher oscillation frequencies. This is the regime of rapid inner shell ionization and Auger relaxation. Both types of strong-field phenomena induce dynamics on femtosecond or faster time scales.