 
|
SYMPOSIA
 |
•••As of February 1, 2002
|
|
|
|
| Science Innovation: Physical Science and Engineering |
Robot Arm Manipulation: Geometric Challenges
Saturday, February 16, 2002 3:00 p.m. - 6:00 p.m. |
|
| Robert Connelly, Cornell University |
| Even some seemingly simple geometric problems can be quite difficult when they have to be solved automatically and algorithmically. One case is the problem of opening a robot arm to be straight when it starts in some folded but non-overlapping configuration while the links of the arm are permitted to swivel around universal joints. By a robot arm we mean a chain of links. Such chains occur in a variety of contexts, as with molecules, actual robot arms, knot theory, computer graphics, etc. It is easy to find configurations of arms in space that are tangled and cannot be opened to be straight. In the plane it seems natural that any arm can be opened, but it is not readily apparent how such a planar arm can be opened staying in the plane without crossing. But recently it has been shown that such planar arms can be opened, and there are some very reasonable geometric principles that can be applied. The geometric problem of finding an opening motion for a planar arm linkage has been proposed by several people independently, and there are even connections with a lemma of Cauchy in 1813. |
| 1 | Opening Arms from Cauchy to Robots | Robert Connelly (Speaker), Cornell University |
| 2 | Reconfiguring Chains: An Algorithmic Perspective | Sue Whitesides (Speaker), McGill University |
| 3 | Locked and Unlocked Polygonal Chains | Erik Demaine (Speaker), Massachusetts Institute of Technology |
| 4 | Opening Arms: A Combinatorial Approach | Ileana Streinu (Speaker), Smith College |
|
Nuclear Matter at the Highest Energies and Densities
Friday, February 15, 2002 2:30 p.m. - 5:30 p.m. |
|
| Samuel Aronson, Brookhaven National Laboratory |
| Nuclear matter at the highest energies and densities is studied in the laboratory with colliding beams of ultrarelativistic heavy ions. Conditions not seen in the universe since 10 µsec after the Big Bang are achievable. Under these conditions phase transitions are expected, between ordinary nuclear matter composed of baryons and mesons and a plasma of freely interacting quarks and gluons. The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, the highest energy such facility in the world, is in its second year of operation. In RHIC gold ions are collided at a center-of-mass energy of 40 trillion electron volts. The results of these collisions are studied in 4 independent experiments. New phenomena are being observed and signatures of the formation of the quark-gluon plasma are being sought. This symposium surveys the status of this search and focus upon a few promising avenues of study opened by the collision energy now available at RHIC. |
| 1 | Relativistic Heavy Ion Physics: The State of the Art | Barbara Jacak (Speaker), State University of New York-Stony Brook |
| 2 | Jet Tomography of Dense Matter | Xin-Nian Wang (Speaker), Lawrence Berkeley National Lab |
| 3 | High PT Phenomena: Current Experimental Results | Federica Messer (Speaker), State University of New York-Stony Brook |
| 4 | Lepton and Dilepton Production: A Theoretical Perspective | Dmitri Kharzeev (Speaker), Brookhaven National Laboratory |
| 5 | Lepton and Dilepton Production: Current Experimental Results | James L. Nagle (Speaker), Columbia University |
|
Experiments with Ultracold Atoms
Saturday, February 16, 2002 9:00 a.m. - 12:00 noon |
|
| Michael D. Crisp, U.S. Department of Energy |
| More than two decades of progress in cooling and trapping of atoms has enabled scientists to perform experiments that were only dreamt of when quantum mechanics was invented. Lasers can be used to slow atoms to speeds below a few centimeters per second. For helium atoms, these speeds would correspond to "temperatures" of a few hundred billionth of a degree Kelvin. If atoms of a gas are cooled and confined to a small enough volume then their quantum mechanical DeBrogile wave lengths begin to overlap and the system can make a phase transition to a single quantum stated called a Bose-Einstein Condensate. The 2001 Nobel Prize in physics was awarded in recognition of the importance of the creation of the first Bose-Einstein Condensate (BEC). The properties of a BEC system brings the strange world of quantum mechanics into our everyday world. Recent developments in atom cooling and trapping technology have also led to the production of degenerate Fermi-Dirac gas. Another consequence of cooling an atom is an increase in the quantum mechanical DeBrogile wavelength that leads to wave properties that are analogous to the interference and diffraction of light. Finally, an experiment to trap and manipulate extremely low temperature positrons and antiprotons to synthesize anti-hydrogen will be discussed. |
| 1 | Atom Optics with BEC's | David E. Pritchard (Speaker), Massachusetts Institute of Technology |
| 2 | Atom Optics on a Chip | Mara Prentiss (Speaker), Harvard University |
| 3 | Bose-Einstein Condensation: Quantum Mechanics Near Zero Temperature | Wolfgang Ketterle (Speaker), Massachusetts Institute of Technology |
| 4 | A Fermi Gas of Atoms | Deborah S. Jin (Speaker), JILA |
| 5 | Cold Antihydrogen | Gerald Gabrielse (Speaker), Harvard University |
|
Roadmaps for Quantum Computing
Sunday, February 17, 2002 9:00 a.m. - 12:00 noon |
|
| Charles W. Clark, National Institute of Standards and Technology |
| Although the processes of information transfer and transformation can be formulated in the abstract, their realization requires physical implementation. The fundamental principles that govern information processing must thus be traced to the basic laws of physics. During the past decade, the quantum-mechanical principles of superposition of states, and of entanglement of states of many-particle systems, have been shown to offer powerful new mechanisms for storage, transmission, and processing of information. Some important problems that are computationally infeasible on a classical computer, such as factorization of large numbers, could be solved in polynomial time on a quantum computer. Although a general-purpose quantum computer still seems to be far in the future, there have now been a number of demonstrations of quantum logic in real physical systems, and there are interesting possibilities for applications of small quantum processors, such as quantum network repeaters. This symposium explores recent developments in the field which may lead to relatively near-term applications. |
| 1 | The Promise of Quantum Computing | Seth Lloyd (Speaker), Massachusetts Institute of Technology |
| 2 | Quantum Computing with Neutral Atoms | Carl J. Williams (Speaker), National Institute of Standards and Technology |
| 3 | Decoherence Free Quantum Computation | K. Birgitta Whaley (Speaker), Univesity of California-Berkeley |
| 4 | Quantum Logic Implementations with Nuclear Magnetic Resonance | Isaac Chuang (Speaker), Massachusetts Institute of Technology |
|
Vortex Matter
Sunday, February 17, 2002 3:00 p.m. - 6:00 p.m. |
|
| Charles W. Clark, National Institute of Standards and Technology |
| Vortex motions have become an important theme common to macroscopic quantum phenomena such as superfluidity, superconductivity, and Bose-Einstein condensation. Large vortex arrays and vortex rings have recently been observed in Bose-Einstein condensates, there are numerous developments in neutron and magnetic imaging of vortex structures in high-temperature superconductors, and the influence of vorticies on superfluid dynamics has been studied over many decades of dynamic range. This symposium brings together examples from these different fields |
| 1 | Bose Condensation and Quantized Vortices in Helium II | Russell J. Donnelly (Speaker), University of Oregon |
| 2 | Vortex Lines, Vortex Lattices, and Vortex Rings in a Bose Einstein Condensate | Peter Engels (Speaker), University of Colorado |
| 3 | Bose-Einstein Condensates at High Rotation Frequencies | David L. Feder (Speaker), National Institute of Standards and Technology |
| 4 | Bose-Einsrein Condensates at High Rotation Frequencies | Yuri Kivshar (Speaker), The Australian National University |
| 5 | Vortex Matter in Type-II Superconductors: Pinning, Melting, and the Peak Effect | Sean Ling (Speaker), Brown University |
|
Conquering the Light: Quantum Storage, Teleportation and Communication
Saturday, February 16, 2002 3:00 p.m. - 6:00 p.m. |
|
| Hossein Sadeghpour, Harvard University |
| The ability to control photons in a coherent fashion is paramount to fast and robust transmission of information. Since photons couple strongly to matter, it is essential that the coherent control of light pulses be performed in a non-destructive manner. Using the principles of quantum superposition, it is possible to exploit destructive interference of optical transitions in atoms to make an otherwise opaque medium, transparent. During the last few years, a series of proposals that exploit this fundamental feature of light-matter interaction have been made for controlling light. Recent realization of imprinting light information in internal states of atoms has demonstrated that storing light is not only possible, but efficient. Unanswered questions with regard to maintaining the coherence of light pulses, i. e. the phase and quantum state, lifetimes of atomic states that limit the storage times, single photon coherent control for secure communication, and a host of application-related issues remain. |
| 1 | Electro-Magnetically Induced Transparency and Slow Light | Steve Harris (Speaker), Stanford University |
| 2 | Using Halted Light Pulses to Store Optical Information | Lene V. Hau (Speaker), Harvard University and Rowland Institute for Science |
| 3 | Quantum Repeater with Atomic Ensembles | Peter Zoller (Speaker), University of Innsbruck |
| 4 | Storing, Communicating and Processing Quantum Information Using Atoms and Light | Mikhail Lukin (Speaker), Harvard University |
|
|
|
|
|
 |
|
