XVIII ICAP 2002 Proceedings - MIT, Cambridge, MA  July 27- August 2, 2002

Online Proceedings of XVIII International Conference on Atomic Physics

Editors: H. R. Sadeghpour (ITAMP),  D. E. Pritchard (CUA), and E. J. Heller (CUA)
Publisher: World Scientific   (contact the publisher for ordering information)
Volume XVIII

ICAP 2002 Invited Talks (speakers are listed in red).

BEC Nobel Symposium
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New BECs
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All-Optical Atomic Bose-Einstein Condensates [PDF]
M. D. Barrett, M.-S. Chang, C. Hamley, K. Fortier, J. A. Sauer, and M. S. Chapman
School of Physics, Georgia Institute of Technology, Atlanta, GA

Abstract: We have created an atomic Bose-Einstein condensate (BEC) using all-optical methods, realizing a long-term objective in the field. Our method is simpler and faster than traditional BEC experiments and offers unique capabilities for atoms and molecules not amenable to magnetic trapping.

Ionization in a Bose-Einstein condensate of metastable Helium: a quantitative monitoring tool [PDF]
A. Aspect, O. Sirjean, S. Seidelin, J. Viana Gomes, D. Boiron and C. I. Westbrook
Laboratoire Charles Fabry de l Institut d Optique, UMR 8501 du CNRS, B.P. 147, F-91403 ORSAY CEDEX, FRANCE

Abstract: Residual ionization in a BEC of 2 3S1 metastable Helium (He*), can be used to monitor in real time the evolution of a single sample of condensate. We use this method, combined to Time Of Flight measurements, to study the decay of the condensate. It has also allowed us to measure 2-body and 3-body ionizing collisions rate constants. This method should allow for the study of the growth of a condensate, in particular in the hydrodynamic regime. We point out the importance of quantum depletion in He* BEC s.

Bose-Einstein Condensates in Magnetic Micro Traps [PDF]
C. Zimmermann, J. Fortagh, H. Ott, S. Kraft, A. GÄunther
UniversitÄat TÄubingen, Germany

Abstract: In a recent experiment we have demonstrated the generation of a Rubidium condensate inside a magnetic micro trap. The lifetime and the heating rate of the atomic cloud at di®erent distances from the trap surface has been determined. A surface induced potential structure of unknown origin has been identi¯ed by observing a periodic fragmentation of the atomic cloud.

New Directions
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Ultracold Fermi gases: towards BCS [PDF]
G. V. Shlypnikov
FOM Institute AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands

Mixtures of degenerate Fermi and Bose gases [PDF]
L. Khaykovich1, J.Cubizolles1, T. Bourdel1, F.Schreck2, G. Ferrari3, L. Carr1, Y. Castin1, C. Salomon1
1 Laboratoire Kastler Brossel, Ecole Normale Sup erieure, 24 rue Lhomond, 75231 Paris CEDEX 05, France
2 Department of Physics, University of Texas at Austin, Austin, TX 7812, USA
3 LENS-INFM, University of Firenze, I-50019, Sesto Fiorentino, Italy

Abstract: We report on experiments with ultra-cold mixtures of fermonic and bosonic lithium gases. 6Li and 7Li are cooled by standard laser cooling techniques and transferred into a Ioffe-Pritchard magnetic trap. Evaporative cooling is performed selectively on the bosonic isotope (7Li), while its fermionic counterpart (6Li) is cooled sympathetically until quantum degeneracy is reached. A 6Li Fermi sea at a temperature of 1/5 of the Fermi temperature, mixed with a 7Li Bose-Einstein condensate is produced. Optical trapping of a Fermi gas with two spin components is described. Finally, by using a Feshbach resonance in 7Li to tune the atomic interaction in the gas, matter wave bright solitons are produced in an optical waveguide. Propagation without spreading over a distance of more than 1 mm is observed.

Beyond AMO
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Phase and absorption gratings for electrons [PDF]
Hong Gao1, Glen Gronniger1, Daniel Freimund1, Alex Cronin2 and Herman Batelaan1
1Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln NE 68588-0111
2Massachusetts Institute of Technology, Cambridge MA 02140

Abstract: We report the experimental realization of phase and absorption gratings for electrons. Phase gratings made with standing waves of light with a periodicity of 266 nm are used to diffract 380 eV electrons [1]. Material gratings of 100 and 200 nm periodicity are used to diffract 500 eV electrons. We are exploring the possibility to use these gratings for low energy electron interferometry.

Quantum Optics with Quantum Dots [PDF]
A. Imamo¯glu
Departments of Electrical & Computer Engineering and Physics University of Califonia, Santa Barbara, CA 93106

Abstract: Semiconductor quantum dots have emerged as promising candidates for studying quantum optical phenomena. Observation of photon antibunching and spontaneous emission limited coherence decay rates have demonstrated that quantum dots behave as artificial atoms. Cavity-quantum electrodynamics (QED) phenomena can be investigated using a single quantum dot embedded inside a photonic nanostructure, where both carriers and photons are confined within sub-micron length scales in all three dimensions. Since quantum dot location inside the cavity is fixed by the growth, this system is free of the stringent trapping requirements that limit its atomic counterpart. Possibility of fabricating photonic nanostructures with ultra-small optical-mode volumes and long photon lifetimes enhances the prospects for applications in quantum information processing.

Single molecule studies of biological processes [PDF]
Steven Chu
Physics Department, Stanford University, Stanford CA 94305
Abstract: A sampling of our recent applications of single molecule fluorescent studies to biological molecules and molecular systems is reviewed. This work represents the combined efforts of over a dozen collaborators whose contributions are cited throughout the paper.

Extra Dimensions, Scalar Fields and CPT: New Tests of Nature's Oldest Force [PDF]
Blaine Heckel
University of Washington

BECs in Optical Lattices
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Beyond mean field physics with Bose-Einstein condensates in optical lattices [PDF]
M. Greiner1,2, O. Mandel1,2, A. Altmeyer1,2, A. Widera1,2, T. Rom1,2, T. W. H¨ansch1,2 and I. Bloch1,2
1Sektion Physik, Ludwig-Maximilians-Universit¨at, Munich, Germany 2Max-Planck-Institut f¨ur Quantenoptik, Garching, Germany

Abstract: By loading Bose-Einstein condensates into a three dimensional optical lattice potential we are able to demonstrate several new intriguing regimes in the physics of ultracold atoms. For example by changing the lattice potential depth we have been able to induce a quantum phase transition from a super uid to a Mott insulating ground state of the system. Furthermore, by rapidly isolating the different potential wells from each other the collapse and revival of the matter wave  eld of a Bose- Einstein condensate has been observed.

Mark Kasevich [Not Submitted]

Cold Molecules
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Buffer-gas Loading and Magnetic Trapping of Molecules [PDF]
John M. Doyle1,2
1Department of Physics, Harvard University
2Harvard-MIT Center for Ultracold Atoms

Abstract: Ultracold and cold molecules have enormous potential for yielding a wealth of new physics and new technologies. Molecules possess several features that greatly increase the possibilities for new interactions, collective quantum states and e ects, collisional processes, fundamental symmetry tests and chemical processes. This is due to 1) the strong interactions between the dipole moments of polar molecules, 2) the rotational and vibrational internal structure of all molecules, and 3) the easily orientable internal electric field of many molecules. The promise of cold and ultracold molecules will only be realized when samples can be prepared with at least the same ease in which we now prepare atomic samples. Several approaches towards trapping of molecules, the key first step toward studying ultracold molecules at high density, have already succeeded: direct cooling of molecules via a buffer gas, mechanical slowing of a pulsed molecular beam with electric fields and photoassociation of alkali atoms. In the ICAP 2002 session on molecules I described some of the current theoretical results and predictions about ultracold molecular systems. Profs. Meijer and Heinzen described results on pulsed beam slowing and photoassociation. This contribution describes some of the key results on buffer-gas loading of molecules.

Dan Heinzen [Not Submitted]

Deceleration and trapping of polar molecules [PDF]
Gerard Meijer1,2,3
1FoM- Institute for Plasmaphysics 'Rijnhuisen', The Netherlands
2Deparment of Molecular and Laser Physics, University of Nijmegan, The Netherlands
3Department of Molecular Physics, Fritz Haber Institute of the Max Planck Society, Berlin Germany

Intense Fields
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Characterization of  attosecond pulse trains from high-harmonic generation [PDF]
H.G. Muller1, P. Agostini2, and Ph. Balcou3
1FOM-Institute for Atomic and Molecular Physics, Amsterdam
2Centre d Etude Saclay
3ENSTA Palaiseau

Abstract: It was demonstrated that high harmonics, generated in a gas jet by a 40-fs laser pulse, have a well-defined phase relation with respect to each other, and that the relative phases result in strong amplitude beating between the various harmonics. Due to this beating, the radiation emerging from the gas jet consists of a train of attosecond pulses (1 as = 10-18s), each 250 as long, and repeating every 1.35 fs. It is described how mixed-color two-photon ionization can be used to determine the relative phases needed for detailed reconstruction of the temporal profile.

Multiple Ionization in Strong Fields [PDF]
J. Ullrich1, R. Dörner2, R. Moshammer1, H. Rottke3, W. Sandner3
1Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg
2Insitut für Kernphysik, August Euler Str. 6, D-60486 Frankfurt
3Max-Born-Institut, Max-Born-Str. 2a, D-12489 Berlin

Abstract: Using  Reaction Microscopes  that enable to detect the vector momenta of several electrons and ions after fragmentation of atoms or molecules, pathways for multiple electron ejection in femtosecond PW/cm2 Laser fields have been explored in unprecedented detail. Classical boundaries for  recollision , which is identified to be the dominant multiple ionization mechanism, are analyzed. The electron-electron correlation in Ne double ionization is explored, Coulomb repulsion between the emerging electrons is demonstrated for Ar double ionization, the importance of excitation   field-ionization mechanisms is elucidated and sub-threshold multiple ionization processes are discussed. Future possibilities as the realization of an  attosecond streak-camera  at free electron lasers are envisaged.

Slow Light and Quantum Control
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Toward Manipulating Quantum Information with Atomic Ensembles [PDF]
M. D. Lukin1, A. Andre1, M. D. Eisaman1, M. Hohensee1, D. F. Phillips2, C. H. van der Wal1,2, R. L. Walsworth2, and A. S. Zibrov1,3
1Department of Physics, Harvard University, Cambridge, MA 02138
2Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138
3P. N. Lebedev Institute of Physics, RAS, Moscow, 117924

Generation and Investigation of Number States of the Radiation Field [PDF]
Herbert Walther
Sektion Physik der Universit¨at M¨unchen and Max-Planck-Institut f¨ur Quantenoptik 85748 Garching, Fed. Rep. of Germany

Abstract: The widely discussed applications in quantum information and quantum cryptography require radiation sources capable of producing a fixed number of photons. This paper reviews the work performed in our laboratory to produce these fields on demand. Two di®erent methods are discussed. The first is based on the one-atom maser or micromaser operating under the conditions of the so-called trapping states. In this situation the micromaser stabilises to a photon number state. Recently, we also succeeded in determining the Wigner function of a single-photon state. The second device, recently realised in our laboratory, uses a single trapped ion in an optical cavity.

Precision Measurement of the Anomalous Magnetic Moment of the Muon [PDF]
William Morse for the g-2 collaboration*
Brookhaven National Lab

Abstract: A precision measurement of the anomalous magnetic moment (g-2) of the muon has been made by the E821 collaboration at BNL. This paper is a written version of a  hot topics  talk at ICAP2002 (Cambridge, MA). The principles of the experiment are discussed, especially the beam dynamics aspects.

Quantum Information
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Quantum information processing and multiplexing with trapped ions [PDF]
D. J. Wineland1, D. Liebfried1, B. DeMarco1, V. Meyer1, M. Rowe2, A. Ben-kish3, M. Barrett1, J. Britton1, J. Hughes4, W. M. Itano1, B. M. Jelenkovic5, C. Langer1, D. Lucas6, and T. Rosenbaud1
1 Time and Frequency Division, NIST, Boulder, CO
2 current address: Optoelectronics Division, NIST, Boulder, CO
3 current address: Dept. of Physics, Technion, Haifa, Israel
4 current address: Dept. of Physics, Univ. of Virginia, Charlottsville, VA
5 Institute of Physics, Begrade, Yugoslavia
6 current address: Dept of Physics, Oxford University, Oxford, UK

Quantum computing and quantum communication with atoms [PDF]
L.-M. Duan1,2, W. D¨ur1,3, J.I. Cirac1,3 D. Jaksch1, G. Vidal1,2, P. Zoller1
1Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria
2 Institute for Quantum Information, Caltech, Pasadena, CA 91125 USA
3Max-Planck Institut f¨ur Quantenoptik, D-85748 Garching, Germany

Abstract: We review recent theoretical proposals for implementation of quantum computing and quantum communication with atoms. The first example deals with the realization of a universal quantum simulator with atoms and ions. The second example outlines the implementation of a quantum repeater with atomic ensembles.

Quantum communication and memory with entangled atomic ensembles [PDF]
Eugene Polzik, Brian Julsgaard, Christian Schori and Jens Sørensen
QUANTOP - Danish National Research Foundation Center for Quantum Optics, Department of Physics and Astronomy, University of Aarhus, Denmark

Quantum information processing and cavity QED experiments with trapped Ca+ ions [PDF]
S. Gulde, H. H¨a®ner, M. Riebe, G. Lancaster, A. Mundt, A. Kreuter, C. Russo, C. Becher, J. Eschner, F. Schmidt-Kaler, I. L. Chuangy, and R. Blatt
Institut f¨ur Experimentalphysik, Universit¨at Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria

Abstract: Single trapped Ca+ ions, stored in a linear Paul trap and laser cooled to the ground state of their harmonic quantum motion are used for quantum information processing. As a demonstration, composite laser pulse sequences were used to implement phase gate and CNOT gate operation. For this, Stark shifts on the qubit transitions were precisely measured and compensated. With a single ion stored inside a high-finesse optical cavity, a cavity mode can be coherently coupled to the qubit transition.

Fundamental Tests
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Observations of Cold Antihydrogen [PDF]
Gerald Gabrielse
Department of Physics, Harvard University, Cambridge, MA 02138

Abstract: ATRAP s e+ cooling of p in a nested Penning trap has led to reports of cold H produced during such cooling by the ATHENA and ATRAP collaborations. ATHENA uses coincident annihilation detection and ATRAP uses  eld ionization followed by p storage. Advantages of the later method include the complete absence of a substantial background of false events intrinsic to the former, and the  rst way to measure which H states are produced. ATRAP enhances the H production rate by driving many cycles of e+ cooling in the nested trap, with more H counted in an hour than the sum of all the other antimatter atoms ever reported. The number of H counted per incident high energy p is also higher than ever observed. The  rst measured distribution of H states is made using a pre-ionizing electric  eld between separated production and detection regions. The high rate and the high Rydberg states suggest that the H is formed via three-body recombination, as expected.

Limits on CP Violation from Electric Dipole Moments [PDF]
Michael V. Romalis
Department of Physics, Princeton University, Princeton, NJ 08544

Abstract: Searches for a permanent electric dipole moment (EDM) provide a unique constraint on violation of CP symmetry beyond the Standard Model. Recent experiments improved the limits on EDMs of 199Hg and the electron. Combined with the limit on the neutron EDM and recent advances in theoretical interpretation, they set very tight constraints on CP violation in Supersymmetry. Many new experimental ideas are currently being explored, promising to improve the EDM limits by several orders of magnitude.

Status of Atomic PNC: Experiment/Theory [PDF]
W. R. Johnson
University of Notre Dame

Abstract: Atomic PNC measurements and calculations are reviewed with emphasis on the 6s -> 7s transition in cesium and the corresponding value of the weak charge Q (133Cs).

Laser Frequency and Time
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Laser Frequency and Time [PDF]
Theodor W. Hänsch
Max-Planck-Institut für Quantenoptik, Garching, and
Sektion Physik, Ludwig-Maximilians Universität, Munich, Germany

Abstract: The following two contributions in this volume are highlighting some remarkable recent developments at the interface between precision laser spectroscopy and ultrafast laser physics. After decades of struggle, we have finally found a practical method for measuring the frequency of light with extreme precision [1]. Femtosecond laser optical frequency comb synthesizers are opening exciting new perspectives for atomic spectroscopy and they can provide the clockwork for optical atomic clocks that will eventually far surpass the accuracy of the best microwave cesium clocks. J. C. Bergquist et al. [2] are reporting on a first optical atomic clock at NIST based on a single trapped Hg+ ion. The contribution by Jun Ye et al. [3] is illustrating the wealth of new opportunities for femtosecond laser frequency combs in the frequency and time domain.

Control of coherent light and its broad applications [PDF]
Jun Ye, R. J. Jones, K. Holman, S. Foreman, D. J. Jones, S. T. Cundiff, J. L. Hall, T. M. Fortier, and A. Marian
JILA, National Institute of Standards and Technology and University of Colorado Boulder, CO 80309-0440, USA

Absract: A remarkable synergy has been formed between precision optical frequency metrology and ultrafast laser science. This has resulted in control of the frequency spectrum produced by mode-locked lasers, which consists of a regular  comb  of sharp lines. Such a controlled mode-locked laser is a  femtosecond optical frequency comb generator.  For a sufficiently broad comb, it is straightforward to determine the absolute frequencies of all of the comb lines. This ability has revolutionized optical frequency metrology and synthesis, and it has also led to recent demonstrations of atomic clocks based on optical frequency transitions. In addition, the comb technology is having a strong impact on time-domain applications, including control of the carrier-envelope phase, precision timing synchronization, and synthesis of a single pulse from independent lasers.

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