Studies Involving Atoms in High Rydberg States

William Marsh Rice University, Houston TX

Investigators

Abstract

The ability to manipulate the internal states of atoms and to control the interactions between neighboring atoms is central to many recent discoveries in science. Advances in this area have resulted in a better understanding of quantum mechanics, the theory that describes the behavior of matter at the microscopic level, and have enabled the new field of quantum information in which quantum mechanics is used as the basis of new technologies related to encryption, information processing, and computing. Manipulating the internal states of atoms involved in chemical reactions makes it possible to produce specific targeted reaction products. Atomic interactions also give rise to collective atomic behavior that result, for example, in magnetism or superconductivity. Tuning such interactions therefore provides insights into such phenomena which, in turn, can enable the design of improved magnetic materials for computer hard drives or improved superconductors for power transmission. This project aims to improve our ability to control and manipulate atomic states and to develop a better understanding of atomic interactions. In specific, this project will heat strontium atoms in a special oven until they boil out of a small hole, forming collimated beam to atoms and then lasers will be used to pump energy into the atoms. After this, electric fields will be applied to the atoms to distort them, they will be allowed to interact, and then other lasers, electric fields, and cameras will be used to determine the results. Similar studies will be done that are complementary to these, using a laser to cool the atoms rather than heating them in an oven. As a starting point, strontium atoms in well-defined initial Rydberg states will be prepared by use of laser light. Techniques developed to manipulate the wave functions of such atoms using a carefully-tailored series of electric field pulses will be exploited to create strongly-interacting Rydberg systems. Initially, a dipole blockade will be employed to create pairs of (weakly-interacting) Rydberg atoms with well-defined separations. Their mutual interactions will then be increased by simultaneously exciting both to some selected higher state, the degree of interaction being tuned by choice of target state (and atom separation). The time evolution of the product two-electron wave packet will be examined to explore energy interchange and search for long-lived configurations where, due to their correlated motions, the electrons remain far apart. Measurements will be extended to include three, or more, strongly interacting Rydberg atoms and explore the onset of many-body effects. Attempts will also be made to create, within a single atom, long-lived two-electron-excited states, i.e., so-called planetary atoms. In addition, control of the interactions between ground state atoms through optical dressing with radiation tuned near resonance with a Rydberg state will be explored. Preliminary measurements have revealed unexpectedly large ground state atom loss rates and the processes responsible will be identified and means to mitigate them sought.