image caption: Approximately 10,000 atoms in a Bose-Einstein condensate that has been split into two packets separated by about 0.5 mm. Each atom is simultaneously in each packet.
Atomic, Molecular, and Optical Physics
The fundamental goal of essentially all atomic and molecular physics is a complete understanding of the interactions of atoms and molecules with electromagnetic fields. These fields may be static or dynamic, originating within the atoms or molecules, or external to them. The experimental Atomic and Molecular groups in the Department of Physics use a wide variety of laser, electro-optical, and microwave equipment to study and manipulate the properties of atoms, molecules, and clusters. As a result, their work is closely connected to the field of optical physics. Optical physics is the study of the generation of optical radiation, the properties of that radiation, and the manipulation and control of radiation by matter. Current research in optical physics includes the development of novel light sources and the exploitation of the quantum properties of light for non-classical communication and precision measurements. The particular research specialization of individual faculty members in the AMO group is summarized below.
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Bloomfield’s research group studies clusters, small aggregates of atoms that fall in between atoms and solids. His group is particularly interested in two areas of cluster science: the study of magnetism in isolated metal clusters and the study of electronic structure in insulator clusters. Their work on magnetism in metal clusters seeks to connect atomic and molecular magnetism with that of condensed matter.
Gallagher’s research focuses on highly excited Rydberg atoms. These atoms interact strongly with external perturbations providing opportunities to quantitatively explore otherwise inaccessible phenomena. Currently the group is investigating microwave multiphoton excitation and ionization with few-cycle microwave pulses, studying collisions between cold (1 milliKelvin) Rydberg atoms in a magneto-optical trap, and examining energy flow between different electronic configurations in atoms with two optically active electrons.
Jones and his students use intense electromagnetic pulses with durations as short as 25 femtoseconds to investigate and control quantum dynamics within atoms and molecules. Current efforts include the development of new techniques for imaging the evolution of electronic wavefunctions within atoms and the position of nuclei within molecules, the control of electron-electron scattering within atoms through the creation of two-electron wavepackets with specific dynamical properties, the use of intense laser pulses to align and/or orient molecules in free space, the generation of coherent, vacuum ultraviolet femtosecond light pulses; and the use of unipolar, THz frequency electric field pulses to simulate coherent charged-particle/atom collisions.
Pfister’s research interests include molecular spectroscopy, nonlinear and quantum optics, and quantum information. His group is especially interested in experimental realizations of quantum information protocols using parametric oscillators and two-photon lasers as intense ultrastable sources of entangled photons. Other interests include the applications of nonclassical light to high-precision measurements, such as Heisenberg-limited interferometry.
Sackett is interested in applying the physics of Bose condensates to practical problems. For instance, by coherently separating and recombining the atom wave in an interferometer, an instrument can be made that is highly sensitive to inertial effects such as rotation, acceleration, and gravity. Construction of such an interferometer, however, requires "atom-optics" elements to confine and direct the matter wave, since traditional optical components like mirrors and lenses are unsuitable. Sackett’s group is working to develop a magnetic wave guide system to serve this purpose. They are also exploring ways that the unusual properties of condensates might be used to advantage in quantum information systems.
Bloomfield: Professor Bloomfield is studying borosilicones, remarkable materials that have been misunderstood for over 70 years. Dismissed as scientifically uninteresting and used as children's toys (e.g., Silly Putty), borosilicones are actually network liquids---dynamic macromolecules that appear elastic on short timescales but exhibit flow on longer timescales. Each borosilicone is a vast covalent network of silicone polymer chains joined by 3-attachment boron crosslinks. At any instant, a borosilicone is a highly-crosslinked elastic material. Because the boron crosslinks are temporary, ... More>
Professor Cates conducts research in three diverse areas spanning atomic, nuclear, and medical physics. Unifying these activities is the use of optical pumping and spin exchange, techniques that make it possible to polarize the spins of electrons, atoms and nuclei using light sources such as lasers. Critical to such research is the study of spin interactions during atomic collisions, spin-relaxation at surfaces, and numerous aspects of laser physics. More>
Highly excited, or Rydberg, atoms interact strongly with external perturbations, providing Prof. Gallagher´s group with opportunities to quantitatively explore otherwise inaccessible phenomena. They are studying the interaction of Rydberg atoms with microwave fields which have frequencies comparable to the Kepler orbital frequency of the electron, a regime in which many phenomena exhibit both classical and quantum behavior. They are examining the properties of relatively high density samples of cold Rydberg atoms using a magneto optical trap. These samples can behave as disordered ... More>
Jones: Much of the current research in atomic physics focuses on the use of extremely well-controlled electromagnetic fields to coherently manipulate the internal and external degrees of freedom of atoms. Jones and his students use lasers to cool and trap atoms, to spin molecules in order to align their axes along a particular direction in the laboratory, and to drive electrons within atoms and molecules in particular directions at specific times. These optical techniques serve as tools which allow them to view very fast processes within atoms and molecules and to perform experiments exploring ... More>
Lehmann: High Resolution Laser Spectroscopy: Development of double resonance techniques for the study of excited vibrational and electronic states of polyatomic molecules; spectroscopy and dynamics of atoms and molecules in helium and molecular hydrogen nanoclusters, determination of the magnitude of intermode coupling constants or intramolecular relaxation rates; development of new spectroscopic methods of extreme sensitivity; development of new sources of tunable, high spectral brightness light; spectroscopic applications to environmental monitoring. More>
Pfister: Olivier Pfister’s research focuses on experimental quantum optics and quantum information. The quantum nature of light (the existence of photons) is a fascinating subject which has turned into a mature experimental field since its inception in the eighties. The research by Pfister’s group, “Quantum Fields and Quantum Information” (QFQI), aims at blazing new trails into the realm of quantum information. In particular, QFQI and their theory collaborators, Nicolas Menicucci and Steven Flammia at the ... More>
Since its first observation in 1995, the process of Bose-Einstein condensation of atomic gases has captured the imagination of many physicists. In this phenomenon, a large number of atoms come to occupy the same quantum state, causing the normally ethereal wave function to act rather as a classical, observable wave. Our research is focused on developing practical applications for these condensates. In particular, we are developing condensate interferometry, in which the atom wave is coherently separated into pieces which are later recombined. The result of the recombination depends ... More>