Atoms in highly-excited so-called Rydberg states are true giants of the atomic world with their outer electrons traveling relatively slowly in orbits with diameters that can approach a fraction of a millimeter. As for any traveler in distant lands, Rydberg electrons are both isolated and vulnerable and their motions can be readily controlled using a carefully-tailored sequence of 'kicks' imparted by a series of electric field pulses. Under the influence of such kicks the Rydberg electron can display a wide variety of behaviors including chaos.This will be exploited to explore the potential of emerging new paradigms for information processing based on the complex behavior of chaotic systems including the use of Rydberg atoms as logic gates, in pattern recognition, and in data mining. The behavior of pairs of Rydberg atoms positioned close to each other such that they interact very strongly will be examined to explore energy interchange and to search for novel long-lived molecular Rydberg states containing two excited electrons. Attempts will also be made to create long-lived atoms containing two excited electrons that are each placed in large orbits and whose motions are stabilized by their mutual interactions and mirror that of a classical planetary system. Measurements will be undertaken in which radio-frequency fields will be employed to drive the motion of the Rydberg electron to probe the behavior of atoms in ground or low-lying excited states when acted upon by ultra-short ultra-intense laser pulses -- in essence replacing the extreme lasers by extreme atoms. These studies with Rydberg atoms will provide a valuable bridge between the nanoscale world of quantum physics and the macroscopic world of Newtonian mechanics.
The present research program will contribute to the training of the scientific workforce by providing students a firm foundation in many areas of physics together with a diverse array of experimental skills in many technologically relevant areas such as high-vacuum technology, lasers, high speed electronics, computerized data acquisition and control, and computer modeling. The experiments on strongly-interacting Rydberg systems will provide valuable new insights into the mesoscopic world and mesoscopic systems such as quantum dots and quantum wells that play a prominent role in exploratory concepts and technologies related to quantum information processing and quantum computing. The work will also provide new information on physics in the ultra-fast ultra-intense regime and speak to the engineering of low-lying atomic (and molecular) states by using attosecond laser pulses to control their properties and behavior, including their chemical reactions. Studies of the response of Rydberg atoms to series of electric field pulses promise new insights into classical chaos and the mathematical tools used to describe it, and furnish a novel laboratory in which to test new paradigms for information processing and data manipulation based on the characteristics of chaotic systems. Rydberg atoms lie at the interface between the quantum and classical worlds and provide a critical bridge between both.
