# January  February  March  April  May  June  July  August September  October November  December

## 1997

### Seminars

• January 18, Tuesday, 10:30 a.m., Pratt Conference Room - AMP Seminar, Prof. Shih-I Chu, Department of Chemistry, University of Kansas: "Atomic and Molecular Processes in Strong Fields"
• January 20, Thursday, 11 a.m., Pratt Conference Room - AMP Seminar, Prof. William Reinhardt, Department of Chemistry, University of Washington: "Stability of Solitons and Vortices in the Gaseous Bose-Einstein Condensate"
• January 25, Tuesday, 2 p.m., Phillips Auditorium - AMP Seminar, Dr. Michael Kuehn, PTB-Berlin: "What's New in Thermometry?"

### Visitors

• Prof. Chris Greene, University of Colorado, JILA, Jan. 31- Feb 29

### Multi-Component and Spinor Bose-Einstein Condensates of Trapped Dilute Vapor [Joint workshop with Rochester Theory Center]

#### Organizers

Eddy Timmermans (Los Alamos Nat'l Lab); Nick Bigelow (Univ. of Rochester)

 Participants Abstracts Directions to Workshop Schedule of Talks

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### Seminars

• February 1, Tuesday, 4 p.m., Pratt Conference Room - AMP Seminar, Dr. David Phillips, Harvard-Smithsonian Center for Astrophysics: "Coherent Population Trapping Clocks using Rubidium" [Abstract]
• February 2, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Dr. Mikhail Lukin: ITAMP: "Nonlinear Optics and Quantum Entanglement with Electromagnetically Induced Transparency"
• February 9, Wednesday, 5:00 p.m., Classroom A-101 - Quantum Coherence Topical Group Seminars  presents Dr. Susanne Yelin, ITAMP: "Atom-atom correlations and superradiance in optically dense media"
• February 15, Tuesday, 4 p.m., Pratt Conference Room - AMP Seminar, Prof. Mahir Hussein, Department of Physics, University of São Paulo: "Theory of Complex Scattering Lengths"
• February 16, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Dr. James Anglin, ITAMP: "Black Holes in Bose Einstein Condensates"
• February 22, Tuesday, 4 p.m., Pratt Conference Room - AMP Seminar, Prof. Chris H. Greene, JILA, University of Colorado: "Collision Physics and Spectroscopy of Complexes with Three Atoms or More" [Abstract]
• February 23, Wednesday, 4.30 p.m., Classroom A-101 - Quantum Coherence Topical Group Seminars  presents Prof. Alexander Sergienko, Boston University: "Hyper-entangled states and femtosecond parametric down conversion" [Abstract]
• February 29, Tuesday, 4 p.m., Pratt Conference Room - AMP Seminar, Steve Gensemer, Department of Physics, University of Connecticut: "Characterization and Control of Ultracold Collisions" [Abstract]

### Visitors

• Prof. Chris Greene, University of Colorado, JILA, until Feb 29
• Dr. Mahir Hussein, Universidade de São Paulo, Feb 7-22

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### Seminars

• March 7, Tuesday, 4 p.m., Pratt Conference Room - AMP Seminar, Dr. David Phillips, Harvard-Smithsonian Center for Astrophysics: "Constraining CPT and Lorentz Violation Using Hydrogen Masers" [Abstract]
• March 8, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. Giacinto Scoles, Princeton University: "Spectroscopy of metal atoms and oligomers in and on liquid helium nanodroplets"
• March 21, Tuesday, 4 p.m., Pratt Conference Room - AMP Seminar, Michael Crescimanno, Berea College: "Estimating the Critical Velocity in Trapped Bose Condensates" [Abstract]
• March 22, Wednesday, 4.30 p.m., Pratt Conference Room - Quantum Coherence Topical Group Seminars  presents Prof. Gerald Gabrielse, Brian Odom, Brian D'Urso, Physics Department, Harvard Univ.: "Probing the Quantum Cyclotron"
• March 23, Thursday, 11 a.m.., Pratt Conference Room - AMP Seminar, Professor Timothy Chupp, Department of Physics, University of Michigan: "Searching for a permanent electric dipole moment of the radon atom"
• March 28, Tuesday, 4 p.m., Classroom A-1- AMP Seminar, Professor Norbert Lutkenhaus, Helsinki Institute of Physics: "Theory for Practical Quantum Cryptography" [Abstract]
• March 29, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Dr. Eddy Timmermans: Los Alamos National Lab: Cold atom traps: old and new aspects of superfluidity

Visitors

• Dr. Mineo Kimura, Yamaguchi University, March 14-19
• Michael Crescimanno, Berea College, Kentucky, March 20-25.

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### Seminars

• April 11, Tuesday, 4 p.m., Pratt Conference Room- AMP Seminar, Dr. Helen Jane Fraser, Department of Physical Chemistry, University of Nottingham: "From Gases to Dust: Surface Interactions in the Interstellar Medium"
• April 12, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Dr. Chandra Raman, MIT: "Shaking and Stirring a Quantum Gas: Light Forces and Bose-Einstein Condensates" [Abstract]
• April 18, Tuesday, 4 p.m., Pratt Conference Room- AMP Seminar, Prof. Q-Han Park, RTC-The University of Rochester and Kyung Hee University: "Soliton Beating"
• April 19, Wednesday, 4.30 p.m., Phillips Auditorium - Quantum Coherence Topical Group Seminars  presents Dr. Holger Schmidt, Research Laboratory of Electronics, MIT: "All-optical modulation using quantum interference in semiconductor quantum wells"
• April 25, Tuesday, 4 p.m., Pratt Conference Room- AMP Seminar, Professor David Micha, Department of Chemistry, University of Florida: õ1]"Femtosecond spectra and dynamics in active media:photodesorption of diatomics"
• April 26, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. Marjatta Lyyra, Temple University: "Prospects for All-Optical Control of Molecular Alignment and RadiativeProcesses"

Visitors

• Prof. Q-Han Park, Kyung Hee University, Korea
• Prof. David Micha, University of Florida, April 1-July 31
• Prof. P. G. Burke, Queen's University of Belfast, April 30-May 21

### Physics and Applications of "Slow" Light

#### Organizers

Mikhail Lukin (ITAMP); Atac Imamoglu (UC Berkeley) and Lene Hau (Harvard)

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### Seminars

• May 3, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. Philip Bucksbaum, Universty of Michigan: "Wavepacket sculpting and learning algorithms"
• May 10, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. E. A. Hinds, University of Sussex: "Atomic mirrors, waveguides and chips" [Abstract]
• May 17, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. Moshe Shapiro, The Weizmann Institute of Science: "Coherent Control of symmetry breaking and chiral molecules purification"
• May 19, Friday, 2 p.m., Pratt Conference Room- AMP Seminar, Prof. Ilya Fabrikant, Department of Physics,
University of Nebraska: "Low-energy behavior of exothermic dissociative electron attachment"

Visitors

• Dr. Michael Fleischhauer, Ludwig-Maximilians-Universitaet, May 1 to September 30
• Dr. Verne L. Jacobs, Naval Research Laboratory, May 15-19
• Prof. Robert Forrey, Penn State Univ., May 15 - July 15
• Prof. P. G. Burke, Queen's University of Belfast, until May 21
• Prof. David Micha, University of Florida, until July 31
• Prof. Moshe Shapiro, The Weizmann Institute of Science,Rehovot, May 1-October 31

### Computational Challenges in Atomic and Molecular Physics

#### Organizers

Mitch Pindzola (Auburn Univ.); Bill McCurdy (LBL), Kate Kirby (ITAMP)

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### Seminars

• June 7, Wednesday, 4 p.m., Pratt Conference Room- AMP Seminar, Dr. Goran Pichler, Institute of Physics, Zagreb, Croatia: "Photoassociation and Pair-Absorption in Superheated Cesium All Sapphire Cells" [Abstract]
• June 27, Tuesday, 4 p.m., Pratt Conference Room- AMP Seminar, Professor Dimitar D. Bakalov, Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia: "Density shift and broadening in antiprotonic helium" [Abstract]
• June 29, Thursday, 4 p.m., Phillips Auditorium- AMP Special Seminar, Dr. M.G.Kozlov, Petersburg Nuclear Physics Institute: "Tests of fundamental symmetries in atoms and molecules" [Abstract]

Visitors

• Dr. Krzysztof Pachucki, Warsaw University, July 1-31
• Prof. Dimitar Bakalov, Bulgarian Academy of Sciences, Sofia, June 1 - July 12
• Dr. Vladimir Korobov, Joint Institute for Nuclear Research, Dubna, June 1-August 31
• Dr. Brendan McLaughlin, Queen's University of Belfast, June 1-July 31
• Dr. James Colgan, Auburn University, June 19-30
• Prof. Robert Forrey, Penn State Univ., until July 15
• Prof. David Micha, University of Florida, until July 31
• Dr. Michael Fleischhauer, Ludwig-Maximilians-Universitaet, until September 30
• Prof. Moshe Shapiro, The Weizmann Institute of Science,Rehovot, until October 31

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### Seminars

• Canceled: July 18, Tuesday, 4 p.m., Phillips Auditorium- AMP Seminar, Dr. Peter Young, Harvard-Smithsonian Center for Astrophysics: "The CHIANTI Atomic Data Base for Astrophysics" [Abstract]

Visitors

• Prof. Stephen Lepp, Universiy of Nevada, Las Vegas, July 24-29
• Prof. Maurice Cohen, The Hebrew Universtiy of Jerusalem, July 25-August 31
• Dr. Krzysztof Pachucki, Warsaw University, July 1-31
• Prof. Sandra Ward, University of North Texas, July 11-14
• Prof. Dimitar Bakalov, Bulgarian Academy of Sciences, Sofia, until July 12
• Dr. Brendan McLaughlin, Queen's University of Belfast, until July 31
• Dr. Vladimir Korobov, Joint Institute for Nuclear Research, Dubna, until August 31
• Prof. Robert Forrey, Penn State Univ., until July 14
• Prof. David Micha, University of Florida, until July 31
• Dr. Michael Fleischhauer, Ludwig-Maximilians-Universitaet, until September 30
• Prof. Moshe Shapiro, The Weizmann Institute of Science,Rehovot, until October 31

### Wave Functions and QED Effects in Few-Electron Atoms

#### Organizer

Gordon Drake (Windsor Univ.), Ian Grant (Oxford)

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### Seminars

• August 18, Friday, 4 p.m., Pratt Conference Room- AMP Seminar, Dr. Vladimir A. Dzuba, School of Physics, University of New South Wales, Australia: "Enhancement of Parity and Time Invariance Violation in the Radium Atom"
• August 24, Thursday, 4 p.m., Pratt Conference Room- AMP Seminar, Prof. Vladimir I. Korobov: Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Russia: "Variational Exponential Expansion and Its Application to the Three Body Coulomb Problem and Nonrelativistic QED"

Visitors

• Prof. Robin Reid, Queen's University of Belfast, August 1-31
• Dr. Brian L. Burrows, Staffordshire University, August 1-24
• Prof. Nikolai Cherepkov, State Univ. of Aerospace Instrumentation, St. Petersburg, August1-September 30
• Dr. Petr Kral: The Weizmann Institute of Science, Rehovot, August 1-September 30
• Prof. Bernard Zygelman, University of Nevada, Las Vegas, August 17-24
• Prof. Maurice Cohen, The Hebrew University of Jerusalem, until August 31
• Dr. Vladimir Korobov, Joint Institute for Nuclear Research, Dubna, until August 31
• Prof. David Micha, University of Florida, until August 31
• Dr. Michael Fleischhauer, Ludwig-Maximilians-Universitaet, until September 30
• Prof. Moshe Shapiro, The Weizmann Institute of Science,Rehovot, until October 31

Workshop

### Coherent Control Mini-Symposium

#### Organizer

Moshe Shapiro (The Weizmann Institute)

 Participants

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### Seminars

• September 5, Tuesday, 4 p.m., Pratt Conference Room- AMP Seminar, Prof. Nikolai Cherepkov, State University of Aerospace Instrumentation, St. Petersburg, Russia: "Photoionization of Fixed-in-Space Diatomic Molecules" [Abstract]
• September 12, Tuesday, 4 p.m., Pratt Conference Room- AMP Seminar, Dr. David Wharmby, Technology Consultant, West Yorkshire, UK: "Radiation data for metal-halide lamps"
• September 19, Tuesday, 4 p.m., Pratt Conference Room- AMP Seminar, Dr. Max Shurgalin, Harvard-Smithsonian Center for Astrophysics: "Precision Measurements of Na-Na and Na-RG Absorption" [Abstract]
• September 20, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. John E. Thomas, Duke University: "Optical Confinement of a Fermi Gas"

### Visitors

• Prof. Jürgen Hinze, Universität Bielefeld, September 1 - December 31
• Dr. Hanno Hammer, The Weizmann Institute of Science, Rehovot, September 25-October 31
• Prof. Nikolai Cherepkov, State Univ. of Aerospace Instrumentation, St. Petersburg, until September 30
• Dr. Michael Fleischhauer, Ludwig-Maximilians-Universitaet, until September 30
• Dr. Petr Kral: The Weizmann Institute of Science, Rehovot, until September 30
• Prof. Moshe Shapiro, The Weizmann Institute of Science,Rehovot, until October 31

### Cold Alkaline-Earth Atoms

#### Organizers

Nils Andersen (University of Copenhagen), Paul Julienne (NIST), Kalle-Antti Suominen (Helsinki Institute)

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## October, 2000

### Seminars

• October 3, Tuesday, 4 p.m., Pratt Conference Room- AMP Seminar, Prof. Nimrod Moiseyev, Dept. of Chemical Physics, The Technion, Haifa, Israel , "High harmonic generation (up to X-rays) from carbon nanotubes"
• October 4, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. Luis Orozco, SUNY at Stony Brook: "Francium Spectroscopy, Recent Advances and Future Directions"
• October 17, Tuesday, 12:30 p.m., Classroom A101- AMP Seminar, Dr. James Burke, NIST: "Using evanescent light fields from optical guides for atom" [Abstract]
• October 18, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Professor Francis Robicheaux, Auburn Univerity: "Pulsed Field Recombination e + p = H (slowly)"
• October 24, Tuesday, 12:30 p.m., Classroom A101- AMP Seminar, Prof. Donald Griffin, Department of Physics, Rollins College: "Recent Developments in the Theory of Electron-Ion Collisions" [Abstract]
• October 25, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. Davd Weiss, Univ. of California, Berkeley, "Light scattering in 3D optical lattices, atomic collisions in 2D and 1D optical lattices"
• October 30, Monday, 12 noon, Classroom A101- AMP Seminar, Mr. Scot Shaw, Department of Physics, Harvard University: "Uncovering Branched Electron Flow" [Abstract]

### Visitors

• Prof. David A. Williams, University College London, October 2-19
• Dr. Cesare Cecchi-Pestellini, Università degli Studi di Firenze, October 12-November 3
• Dr. James Burke, NIST - Gaithersburg, October 16-27
• Prof. Donald C. Griffin, Rollins College, October 16-30
• Dr. I. John Danziger, Osservatorio Astronomico di Trieste, Octrober 18-22
• Prof. Thomas Gorczyca, Western Michigan University, October 24 - November 11
• Prof. Moshe Shapiro, The Weizmann Institute of Science,Rehovot, until October 31
• Dr. Hanno Hammer, The Weizmann Institute of Science, Rehovot, until October 31
• Prof. Jurgen Hinze, Universität Bielefeld, until December 31

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## November, 2000

### Seminars

• November 1, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. Wonho Jhe: Seoul National University: "Atom Optics in Hollow Optical Systems"
• November 2, Thursday, 11 a.m., Pratt Conference Room- AMP Seminar, Professor Thomas Gorczyca, Western Michigan University: "New Characterizations of Doubly-Excited Atomic States" [Abstract]
• CANCELLED: November 6, Monday, 12 noon, Classroom A101- AMP Seminar, Professor John Stanton: University of Texas: "Formulation, Implementation and Application of Second and Higher Derivatives Using Coupled Cluster Theory" [Abstract]
• November 13, Monday, 12 noon, Classroom A101- AMP Seminar, Dr. Michael G. Moore, ITAMP, Harvard-Smithsonian CFA: "Scattering laser light from Bose Einstein condensates and degenerate Fermi gases" [Abstract]
• November 15, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. C. Lewis Cocke, Kansas State Univ.: "Ion and Electron Momentum Imaging Applied to Charged-particle and Photon Interactions with Atoms and Molecules" [Abstract]
• November 27, Monday, 12 noon, Classroom A101- AMP Seminar, Dr. Jürgen Hinze, Universität Bielefeld: "The ro-vibrational states of H3+ and the adiabatic approximation"
• November 29, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Prof. Li You, Georgia Institute of Technology, "Quantum Computing with Trapped Atoms and Photons"
• [NEW TIME AND PLACE]November 30, Thursday, 1:30 p.m., Phillips Auditorium -- Special AMP Seminar, Prof. Li You, Georgia Institute of Technology: "Collapse dynamics of a Bose-Einstein condensate"
•

### Visitors

• Dr Cecil Laughlin, School of Mathematical Sciences, University of Nottingham, November 15-December 15, 2000
• Dr. Cesare Cecchi-Pestellini, Università degli Studi di Firenze, until November 3
• Prof. Jurgen Hinze, Universität Bielefeld, until December 31
• Prof. Thomas Gorczyca, Western Michigan University, until - November 11

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## December, 2000

### Seminars

• December 4, Monday, 12 noon, Classroom A101- AMP Seminar, Dr.Cecil Laughlin, University of Nottingham: "Calculation of spectra and oscillator strengths for neutral Ca and Zn"
• December 13, Wednesday, 4:30 p.m., Jefferson Lab, Room 356 - Joint Atomic Physics Colloquium, Dr. Jens Gundlach, Univ. of Washington: "New measurement of gravitational constant G"
• December 18, Monday, 12 noon, Classroom A101- AMP Seminar, Dr. Alois Mair, Harvard-Smithsonian Center for Astrophysics, "Measuring the shape of single photons" [Abstract]

### Visitors

• Prof. Jurgen Hinze, Universität Bielefeld, until January 31

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### "Hyper-entangled states and femtosecond parametric down conversion" Speaker: Prof. Alexander Sergienko

#### Boston University

Time : Wednesday, February 23, 4:30 pm

Place : Harvard-Smithsonian Center for Astrophysics
Classroom A-101

A pair of photons (two-photon state) generated in the nonlinear process of spontaneous parametric down conversion (SPDC) is strongly entangled in energy, time, polarization, and space (momentum). The simultaneous entanglement in more than one pair of quantum variables (hyper-entanglement) serves as a powerful tool in fundamental studies of foundations of the quantum theory and in the development of novel information processing techniques such as quantum cryptography.

### Characterization and Control of Ultracold Collisions

Steve Gensemer

Department of Physics
University of Connecticut

4:00 PM Tuesday, February 29, 2000
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

We have developed several new techniques for observing and altering ultracold collisions in laser-cooled Rb. We have found that the trapping laser in a typical magneto-optical trap (MOT) can increase inelastic collision rates by more than an order of magnitude. We have
also observed ultracold collision dynamics in the temporal domain for the first time, by using a series of laser pulses that interact with a colliding pair of atoms at different internuclear distances. Together with other experiments that use repulsive or attractive molecular potentials to reduce or increase inelastic or elastic collision rates, we
are developing the tools to understand and utilize the extremely long-range molecular potentials involved (R > 300 bohr radii), which cannot be studied using conventional spectroscopy.

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### "Constraining CPT and Lorentz Violation Using Hydrogen Masers"

Dr. David Phillips

Harvard-Smithsonian Center for Astrophysics

4:00 PM Tuesday, March 7, 2000
Pratt Conference Room

We measure the frequency of the Zeeman (F=1, delta m_F=1) transition via a double resonance technique in a hydrogen maser as the orientation of the quantization axis (set by the magnetic field) changed relative to the fixed stars due to the rotation of the Earth. A bound on a sidereal variation in this frequency difference places a limit on a combination of
Lorentz-violating parameters in a recently developed standard model extension. In the context of this extension, our result places the most stringent clean bound to date on Lorentz and CPT violations of the proton. Current results will be presented.

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### "Estimating the Critical Velocity in Trapped Bose Condensates"

Michael Crescimanno

Department of Physics
Berea College

4:00 PM Tuesday, March 21, 2000
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

ABSTRACT: We use a modified Thomas-Fermi approximation to estimate analytically the critical velocity for the formation of vortices in harmonically trapped BEC. We compare this analytical estimate to numerical calculations and to recent experiments on trapped alkali condensates.

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### "Theory for Practical Quantum Cryptography"

Prof. Norbert Lutkenhaus

Helsinki Institute of Physics

4:00 PM Tuesday, March 28, 2000
Classroom A-1
Harvard-Smithsonian Center for Astrophysics

Abstract:
Quantum Cryptography bears the promise of provable unconditional secure communication. Many groups have by now demonstrated that they have the tools to send quantum signals over distances of more than 10-40 km with low error rates. However, there are many traps outside of the safe region of idealized signals and protocols. I will show some traps and map out a safe region for practical quantum cryptography.

### Atomic Mirrors, Waveguides and Chips

#### University of Sussex

Lasers can produce clouds of atoms at micro-Kelvin temperatures where the de Broglie wavelengths are rather long. Atom optics is the subject of manipulating these cold atoms using mirrors, lenses, waveguides and traps, much as photons are controlled using the traditional tools of optics. For example, our group has developed a magnetic atom mirror,
shown here focussing a bouncing cloud of atoms.

My talk will show some movies of cold atom clouds being manipulated. From the viewpoint of basic physics these atoms are a suitable fluid for the study of weakly interacting quantum particles in 3D. Miniature atom traps and de Broglie waveguides can reduce the number of spatial dimensions to produce quantum wells, wires or dots for neutral atoms.
These emerging techniques for manipulating atoms on sub-micron length scales are also interesting in the context of applied physics. Several groups are developing single-mode waveguides and planar structures in which neutral cold atoms can propagate along prescribed paths. This could provide the basis for a new technology similar to integrated
electronics, but based on the flow and interaction of neutral atoms rather than electrons or holes. I will talk about these topics with particular emphasis on recent progress at SCOAP using micron-sized magnetic structures written on video tape. I will describe how atom
chips might be realised and how they might be used to construct a quantum logic gate. This approach is particularly appealing for quantum computing as the decoherence times for neutral atoms held by static fields will probably be rather long.

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### "PHOTOASSOCIATION AND PAIR-ABSORPTION IN SUPERHEATED CESIUM ALL SAPPHIRE CELLS"

Dr. Goran Pichler

Institute of Physics
Zagreb, Croatia

4:00 PM Wednesday, June 7, 2000
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

The results of absorption measurements in a dense superheated cesium vapor generated in all sapphire cells will be presented and discussed. Due to a very effective thermal destruction of Cs2 molecules a number of diffuse and satellite bands appear in absorption spectrum, which are not easily visible in saturated cesium vapor. From the temperature
dependence of diffuse spectral features we can distinguish short-range singlet transitions from temperature independent spectral features that stem either from a shallow lowest triplet state or from the long-range photoassociation into triplet or singlet Cs2 molecule.
Implications of the observed Cs satellite and diffuse bands in the field of ultracold Cs atom collisions and ultracold molecule formations will be discussed.

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### "Density shift and broadening in antiprotonic helium"

Professor Dimitar D. Bakalov

Institute for Nuclear Research and Nuclear Energy
Bulgarian Academy of Sciences, Sofia, Bulgaria

4:00 PM Tuesday, June 27, 2000
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Antiprotonic helium atoms are formed when antiprotons are stopped in a helium target. Comparison of theory with precision laser spectroscopy measurements of the metastable states of antiprotonic helium is due to provide new better data for the dipole magnetic moment of antiprotons with an accuracy that exceeds the present level by order(s) of magnitude. We calculate by ab initio methods the density shift and broadening of the 13 transition lines observed by now and remove this way an uncertainty of up to 10 ppm in the laser spectroscopy data on antiprotonic helium. The results have been obtained in the impact approximation using an interatomic interaction potential calculated with the symmetry-adapted perturbation theory, and are in perfect agreement with experiment.

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 Tests of fundamental symmetries in atoms and molecules M.G.Kozlov Petersburg Nuclear Physics Institute For a long time atoms and molecules were used to study violation of the spacial inversion symmetry (P) and the time-reversal invariance (T). At present P-odd effects in atoms are accurately measured for several heavy atoms and the remarcable agreement with the predictions of the standard model is established. However, there seems to be some signs of a descrepancy between theory and experiment on the 1% scale, which can indicate some new physics beyond the standard model, or some drawbacks in modern atomic theory. The long standing search for the T-odd effects in atoms has resulted in a very stringent limit on the electric dipole moment (EDM) of the electron. Theory predicts the much bigger enhancement factors for the EDM of the electron for polar diatomic molecules. That gives us a chance to improve current limit on the EDM of the electron by few orders of magnitude and test the range where predictions of the supersymmetric models lie.

### The CHIANTI Atomic Database for Astrophysics

Dr. Peter Young

Harvard-Smithsonian Center for Astrophysics

4:00 PM Tuesday, July 18, 2000
Phillips Auditorium
Harvard-Smithsonian Center for Astrophysics

Abstract:

The CHIANTI atomic database contains energy levels, radiative decay rates and electron collision strengths for virtually all astrophysically important ions. The database further contains a set of IDL routines that allow the computation of synthetic spectra from these data, as well as the study of temperature and density diagnostics from the individual ions.

A key feature of the database is that the electron collision data for each transition is assessed and fitted in a uniform manner. The IDL routines used in the fitting will be demonstrated.

Version 3 of the database is soon to be released, and will provide comprehensive coverage of emission lines at X-ray wavelengths, appropriate for the analysis of data from the Chandra and XMM-Newton missions.

### PHOTOIONIZATION OF FIXED-IN-SPACE DIATOMIC MOLECULES

Prof. Nikolai Cherepkov

State University of Aerospace Instrumentation
St. Petersburg, Russia

4:00 PM Tuesday, September 5, 2000
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Abstract:

The Random Phase Approximation (RPA) successfully applied earlier for atomic photoionization cross section calculations, has been generalized for diatomic molecules. The results of the RPA calculations of photoionization of H2 and N2 molecules will be presented. The first RPA calculations for K-shells of N2 molecule demonstrated a very important role of many-electron correlations which reveal itself, in particular, in the angular distributions of photoelectrons ejected from fixed-in-space molecules. The theoretical
prediction is supported by recent experimental measurements. The results of the first complete experiment in photoionization of C and O K-shells of fixed-in-space CO molecule (Photon Factory, Japan) will be presented and compared with theoretical calculations in the Hartree-Fock approximation.

### Precision Measurements of Na-Na and Na-RG Absorption

Max Shurgalin

Harvard-Smithsonian Center for Astrophysics

4:00 PM Tuesday, September 19, 2000
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Precision high resolution measurements of Na dimer and Na-rare gas absorption over the wavelength range 400-850 nm are presented. The experimental apparatus and measurement techniques are described in detail. Results and comparisons with theoretical calculations are discuused. The measurements obtained allow comprehensive tests of theoretical
calculations and critical evaluation of available molecular data of the sodium dimer and sodium rare gas systems.

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### Ion and Electron Momentum Imaging Applied to Charged-particle and Photon Interactions with Atoms and Molecules

C.L.Cocke

J.R.Macdonald Laboratory

Physics Dept.

Kansas State Univ.

Manhattan, KS 66506

COLTRIMS (COLd Target Recoil Ion Momentum Spectroscopy) combines fast imaging detectors with a supersonically cooled gas target to allow the charged particles from any ionizing collision, including both recoil ions and electrons, to be collected with extremely high efficiency and with fully measured vector momenta. Since all particles are measured in event mode, the full multi-dimensional momentum space is mapped. I will review several examples of the use of this technique to study two- , three- and four-body final states created in ionizing interactions of photons and charged particles with He, CO and D2 . The examples may include: (1) Low-energy continuum electron production shows evidence for molecular orbitals promoted into the continuum;(2) Capture from D2 by very slow Xe 26+ projectiles shows Coulomb explosion peaks modified by tidal forces exerted on the fragments by the projectiles; (3) Photodisintegration of CO by synchrotron light near C K edge show strong diffraction images of the outgoing electron waves characteristic of the molecular potential; (4) Application of the technique to the double ionization of D2 short intense laser pulses reveals a Coulomb explosion peak not visible with previous approaches.

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### Using evanescent light fields from optical guides for atom"

Dr. James Burke

NIST

4:00 PM Tuesday, October 17, 2000
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Electromagnetic fields have been used extensively to manipulate and control atoms. In this presentation, I will the discuss the possibilities of using two-color evanescent fields leaking out of optical structures to locate and move atoms so that they can interact, interfere, and
entangle. Applications range from atom transport and deposition to quantum computing. In particular, both linear waveguides and ring resonators are considered. Finite-difference and finite-difference time domain methods are used to solve for and propagate the optical modes and evanescent near-fields of these optical guides. The atomic trapping potentials are related to the local squared electric field strength. Once trapped, the atoms can be moved by varying the relative phase difference between two counterpropagating modes. Linear waveguides in a railroad configuration allow an interacting network of atoms to be manipulated. Optical ring resonators can be coupled efficiently through evanescent fields to linear waveguides. Standing waves in the resonators produce atom "turnstiles". Based on these examples, I discuss the design features that must be addressed to implement these optical structures for use in atom optics.

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### Recent Developments in the Theory of Electron-Ion Collisions"

Prof. Donald Griffin

Department of Physics
Rollins College

12:30 Tuesday, October 24, 2000
Classroom A101
Harvard-Smithsonian Center for Astrophysics

In recent years, there have been significant developments in the theoretical treatment of electron-ion collisions. This talk will focus on some of these as they pertain to electron-impact ionization and excitation of multi-electron ions. In particular, we will discuss and compare two methods for treating electron-impact ionization: the $R$-matrix with pseudo state method and the time-dependent close-coupling method. With respect to
electron-impact excitation, we will consider several advances that have allowed for more complete and accurate $R$-matrix treatments of electron-impact excitation between individual levels, including a novel method for removing the contributions from pseudo resonances and an intermediate-coupling frame transformation method based on quantum-defect theory. We will also discuss on-going efforts to allow for the application of these methods to more complex systems of current interest to astrophysics and controlled nuclear-fusion research.

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### Uncovering Branched Electron Flow

Mr. Scot Shaw

Department of Physics
Harvard University

12:00 Monday, October 30, 2000
Classroom A101
Harvard-Smithsonian Center for Astrophysics

Recent collaborations with the Westervelt experimental group have led to the discovery and exploration of branching electron flow in a two-dimensional electron gas. After passing through a point contact, electrons are observed to propagate in persistent, narrow, branching
channels rather than a smoothly spreading fan. Furthermore, these data show coherent effects well beyond the distance where 'thermal smearing' would be expected to wipe them out. In this talk, I will first introduce this phenomenon with experimental data and a description of the experimental setup. I will then briefly describe the numerical method and
the model used to explore the phenomenon. I will present classical and quantum data, which demonstrate that the observed branching phenomenon is largely a classical one, and give our explanation of the origins of the branches and of coherent effects beyond the thermal length.

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### "New Characterizations of Doubly-Excited Atomic States"

Prof. Tom Gorczyca

Western Michigan University

11:00 AM Thursday, November 2, 2000
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

With the advent of 3rd-generation synchrotron radiation facilities, highly-resolved and differential photoelectron spectroscopy studies have recently discovered unexpected behaviors of doubly-excited resonances. In response to these results, theoretical analyses have revealed interesting new resonance properties that are observable in high-resolution partial cross sections, but not in total or lower-resolution partial cross sections. As one example, mirroring resonances have been predicted when certain weak mixing conditions
hold, where the detection of resonances, or their asymmetric features, are only possible through highly-resolved differential measurements. A second example involves measuring the emitted photons following radiative stabilization of photoexcited 2lnl' states in helium. Here a breakdown of nonrelativistic predictions occurs due to the spin-orbit mixing with dipole-forbidden resonances, causing periodic redistributions between the fluorescence and alternate ionization signals. A combination of multichannel quantum defect theory, optical
potential, and frame transformation methods allows for a complete quantification of these oscillatory effects, and large-scale R-matrix calculations reproduce the experimentally observed features quite well. The significant effect on near-threshold photoionization, and
the more recently observed external electric field influences, will also be addressed.

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### Formulation, Implementation and Application of Second and Higher Derivatives Using Coupled Cluster Theory

Prof. John Stanton

University of Texas

12:00 PM Monday, November 6, 2000
Classroom A101
Harvard-Smithsonian Center for Astrophysics

Abstract:

Perhaps the most important advances for facilitating widespread application of molecular quantum mechanics to problems of interest to chemists have been those associated with the development of strategies for calculating analytic energy derivatives routinely and efficiently. Beginning with Pulay's work on Hartree-Fock derivatives, this field has been a focus of effort for many groups for the last quarter century. Efficient implementations of analytic first derivatives are now available for almost all methods that constitute the alphabet soup of quantum chemical approaches, and prove enormously useful in studying potential energy surfaces governing molecular vibration and chemical reactions. Until recently, analytic second derivative methods were limited to only the simplest methods. In the last few years, methods have been developed for the efficient calculation of analytic second derivatives of the energy at levels of theory that include sophisticated treatments of electron correlation. By using a strategy that differs markedly from that usually advocated for analytic second derivative calculations, it is possible to design algorithms that are free of disk-space bottlenecks''. These have been implemented for several levels of many-body perturbation
theory and the coupled-cluster approximation, and allow the treatment of systems containing more than 200 basis functions on modestly-equipped workstations.

One of the more promising avenues for application of these methods is in the calculation of quantities that more closely resemble experimental observables than those traditionally obtained by quantum chemistry. For example, fundamental frequencies are measured in the laboratory while harmonic frequencies are routinely reported in quantum-chemical studies,
effective rotational constants and internuclear distances are measured while $B_e$ and $r_e$ values are most easily obtained by calculation. However, more appropriate estimates of experimental quantities can be achieved if anharmonic force fields are available for the molecules of interest. Using analytic second derivative techniques, all cubic and relevant (semidiagonal) quartic force constants can be calculated efficiently and {\it accurately} through an automated finite-difference procedure. In this talk, the analytic second derivative
theory and its implementation are briefly discussed. Following this, the method is illustrated by selected applications including the vibration-rotation interaction constants of benzene, an empirical deduction of the equilibrium structure of dioxirane, the fundamental frequencies of diborane and highly accurate calculations of nuclear magnetic shieldings.

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### Scattering laser light from Bose Einstein condensates and degenerate Fermi gases

Dr. Michael G. Moore

ITAMP
Harvard-Smithsonian CFA

12:00 PM Monday, November 13, 2000
Classroom A101
Harvard-Smithsonian Center for Astrophysics

Abstract: A theoretical framework inspired by quantum optics has been developed to describe many aspects of the interaction between Bose Einstein condensates and off-resonant light fields. Topics to be addressed are: parametric amplification of coupled atomic and optical fields, matter-wave superradiance, the generation of entangled atom-photon pairs, and, time permitting, the possibility to observe "Bose enhancement" in
degenerate Fermi gasses.

### "Measuring the Shape of Single Photons"

Dr. Alois Mair
Harvard-Smithsonian Center for Astrophysics

12:00 PM Monday, December 18, 2000
Classroom A101
Harvard-Smithsonian Center for Astrophysics

Abstract:
Depending upon its mode, light can have an orbital angular momentum. Such orbital angular momentum is independent of polarization, but is connected to phase singularities in the wave field. A method to detect phase singularities of single photons will be introduced here. Our experiment shows that photon pair creation (spontaneous parametric downconversion) conserves the orbital angular momentum for each single photon pair emission; moreover, the orbital angular momenta of the photon pair are entangled.

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