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ITAMP CALENDAR

2001

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Previous ITAMP Calendar Events

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January, 2001

Seminars

 

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February, 2001

Seminars

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March, 2001

Seminars

Visitors

Workshops

Workshop Title

A Topical Group on Quantum Entanglement and Many-Body Systems

Date

March 12-16, 2001

Organizers

Mikhail Lukin (ITAMP); Peter Zoller Univ. of Innsbruck
 

Participants

Accommodations 

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April, 2001

Seminars

Visitors

Workshops

Workshop Title

Complex Phenomena Involving Rydberg Atoms and Molecules

Date

April 26-28, 2001

Organizers

Francis Robicheaux (Auburn) and Robert Jones (Dept. of Physics, Univ. of Virginia)

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May, 2001

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June, 2001

Seminars

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Workshops

Workshop Title

Atomic, Molecular, and Optical Physics at Surfaces [Go to workshop]

Date

June 14-16, 2001

Organizers

David Micha (Univ. of Florida), Uwe Thumm (Kansas State) and John Tulley (Yale Univ.)

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July, 2001

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August, 2001

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September, 2001

Seminars

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Workshops

Postponed to November 29-December 1, 2001

 Tests of Fundamental Symmetries in Atoms and Molecules

Originally scheduled September 20-22, 2001

Organizers: Andrei Derevianko, Walter R. Johnson, and Ronald Walsworth

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October, 2001

Seminars

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November, 2001

Seminars

Visitors

Workshops

 Beyond BEC: Ultracold Atoms beyond Mean-field Physics

November 2-3, 2001

Organizers: James Anglin (CUA/MIT), Kate Kirby (ITAMP), Daniel Kleppner (MIT), Mikhail Lukin (Harvard)

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 Tests of Fundamental Symmetries in Atoms and Molecules

November 29-December 1, 2001

Organizers: Andrei Derevianko, Walter R. Johnson, and Ronald Walsworth

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December, 2001

Seminars

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Abstracts

 Magnetic trapping of underrepresented atoms and molecules

Mr. Jonathan D. Weinstein


Department of Physics
Harvard University

12:00 PM Monday, January 15, 2000
Classroom A101
Harvard-Smithsonian Center for Astrophysics

Abstract:

We have confined $10^8$ molecules of ground-state calcium monohydride, CaH ($X^2\Sigma$), in a static magnetic trap at 400mK. CaH molecules were produced via laser ablation. Loading of these molecules into a 3.0 T (2.0K) deep magnetic trap is accomplished through the use of a cryogenically cooled $^3$He buffer gas.

Using similar techniques, we have simultaneously trapped boson and fermion isotopes of atomic chromium, with the goal of creating a Fermi degenerate gas. Initial evaporative cooling experiments have been performed, and preliminary collisional properties measured.

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 The CHIANTI atomic database for astrophysics

Dr. Peter Young


Harvard-Smithsonian Center for Astrophysics

12:00 PM Monday, January 22, 2001
Classroom A101
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 individual ions.

Version 3 of the database was released recently, and provides comprehensive coverage of emission lines at X-ray wavelengths, suitable for the analysis of data from the Chandra and XMM-Newton missions.

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  "Quantum Cloning"

Prof. Mark Hillery
Department of Physics
Hunter College of CUNY

11:45 AM Monday, February 12, 2001
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Abstract

It has been known since the work of Wooters and Zurek in 1983 that it is imposible to build a device that will perfectly copy a quantum system. For example, one cannot construct a device that has as its input a spin-1/2 particle and produces at its output two spin-1/2 particles in the same quantum state as the input particle. This means that quantum information, unlike classical information, cannot be copied. It is possible, however, to make imperfect copies of quantum systems, and over the last 5 years considerable understanding has been gained of how good these copies can be and how, in principle, they can be produced. In the last year some experimental results have also been reported. These developments will be reviewed.

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 "Laser Cooling in a High Finesse Cavity"

Dr. Frank Narducci
NRL

4:00 PM Tuesday, February 13, 2001
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Abstract:

In this talk, I explore from first principles the effect that the presence of a high finesse cavity
with an injected signal far from atomic resonance may have on an atom. Specifically, I will try to answer whether the cavity can enhance the cooling effect of a far off resonant field.

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 Spinor Bosonic Atoms in Optical Lattices: Symmetry Breaking and Fractionalization

Dr. Eugene Demler

Physics Dept. Harvard University

March 13, Tuesday 10:45 am Pratt Conference Room


Abstract:


A system of cold spin-1 Bose atoms with antiferromagnetic interactions in an optical lattice is considered. It is shown that spin dynamics in a single site is described by a rigid rotor problem with parity constraint on possible angular momenta. Coupling between the lattice sites is introduced via tunneling of the atoms and leads to a variety of broken symmetry phases, including a usual polar phase, a condensate of singlet boson pairs, and a crystal spin
nematic phase. Exotic fractionalized phases of spinor BEC are suggested and discussed in the language of topological defect condensation and $Z_2$ lattice gauge theory. An interference type experiment is proposed that may distinguish between various broken symmetry states.

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Decoherence in collective quantum memories

 Prof. Michael Fleischhauer

Universitat Kaiserslautern

March 15, Thursday 10:45 am Pratt Conference Room

Abstract:

The influence of several decoherence mechanisms such as atom number fluctuations, lack of initial state purity, random spin flips and atomic motion on a collective quantum memory for photon states is discussed. It is shown that there are equivalence classes of collective storage states. Transitions within these classes caused by environmental influences does not affect the stored quantum state and lead to a relative robustness of the collective memory. An operational approach for (incomplete) cloning of the stored quantum state is discussed.

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  Rigorous approach to the problem of ultraviolet divergencies in dilute Bose gases

Dr. Maxim Olshanii
University of Southern California

11:00 AM Thursday, March 22, 2001
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Abstract

We have found an expression for the full many-body Green's function of N pairwise finite-range interacting atoms, in a form of a chain fraction involving two-body T-matrices only, with no explicit presence of the interaction potentials themselves. We show that in the limit of infinitely small potential range, this expression reduces to the Green's function for N atoms interacting via a generalized pseudo-potential, function of a free parameter \Lambda. Using this
\Lambda-freedom we resolve all inconsistensies of the Hartree-Fock-Bogoliubov formalism known so far, with no ad hoc modifications of the theory.

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 Nonsemiclassical effects in curve crossing

Dr. Vladimir Yurovsky


Tel Aviv University, Israel

11:45 AM Monday, March 26, 2001
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

ABSTRACT

Nonsemiclassical effects in two-state and multistate curve crossing are considered. In the two-state case such effects appear on crossing of nonlinear potentials and in systems described by nonlinear equations, e.g. transitions between atomic and molecular BECs.

Multistate curve crossing in linear potential grids involving two sets of parallel potentials is considered here using an quasidegeneracy approximation. The approximation describes phenomena, such as counterintuitive transitions and saturation (incomplete population transfer), not predictable by the assumption of independent crossings. Also, a new kind
of oscillations due to quantum interference (different from the well-known St\"uckelberg oscillations) is disclosed, and its nature discussed. The approximation can find applications in many fields of physics, where multistate curve crossing problems occur.

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 "Breakthrough in the investigation of the 5d elements: history,
current situation and perspectives"

Dr. Vladimir Azarov


Research and Development
Parametric Technology Corporation

11:45 AM Monday, April 9, 2001
Phillips Auditorium
Harvard-Smithsonian Center for Astrophysics

Abstract:

The history, current situation and perspectives of the investigation of the elements with the open 5d-subshell are discussed. The study of spectra and structures of atoms and ions of the elements Ta,W,Re,Os,Ir,Pt,Au,Hg,Tl,Pb and Bi (atomic numbers 73-83) is under consideration. The ions of interest have the ground state configuration from 5d^2 through 5d^8 and ionization through 13.

The reasons why the spectra of these ions are currently of the very interest are given. Difficulties in experimental investigation of the ions are discussed. The latest theoretical, experimental and methodological achievements that highly accelerate analyses of the
most complex spectra and raise the reliability of the data are presented.

The data will permit to apply and check new theoretical methods giving a chance to determine higher order relativistic and correlation effects experimentally and to study them systematically. These effects are more important and prominent in the heavy 5d elements compared to the 3d and 4d elements.

Within several years the amount of obtained data will be doubled compared to the whole history of studying the 5d ions of the elements from Ta through Bi. The expected jump in quantity (in the amount of experimental data) will provide a jump in quality.

  Ab initio calculation and semiclassical dynamics of the
photodissociation of O_2 in the Herzberg continuum

Dr. Gerrit C. Groenenboom


Institute of Theoretical Chemistry
University of Nijmegen, The Netherlands

11:45 AM Monday, April 16, 2001
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Abstract:

The photodissociation of oxygen is the primary process in the ozone formation in the atmosphere. Even though the three transitions involved in the photodissociation of oxygen in the Herzberg continuum are electric dipole forbidden they account for about 90% of the O_2
photodissociation in the lower stratosphere. Since the transitions are of mixed parallel/perpendicular character the anisotropy parameters give detailed information on the photodissociation mechanism. To determine these parameters Buijsse et al. [1] performed
ion-imaging experiments at 236, 226, and 204 nm. The energy resolutionof the experiment was sufficient to distinguish between the three fine-structure components of the O(^3P_{j=2,1,0}) product. The results could neither be explained by a diabatic nor by an adiabatic photodissociation model. We present {\em ab initio} potential energy curves and O-O separation dependent spin-orbit coupling parameters. The A^3\Sigma_u^+ Herzberg state is asymptotically degenerate with the 2 ^3\Sigma_u^+ state. Semiclassical trajectory calculations show that spin-orbit coupling induced transitions occur in a region where
the mixing between the nearly degenerate ^3\Sigma_u^+ states is incorrectly described in a standard CASSCF+MRCI calculation. A solution for this problem employing undistorted atomic orbitals is presented. This method also allows the computation of meaningful nonadiabatic couplings between the sigma states. This nonadiabatic coupling turns out to be essential for a proper description of the photodissociation reaction.

(1) B. Buijsse, W.J. van der Zande, A.T.J.B. Eppink, D.H. Parker, B.R. Lewis, and S.T. Gibson, J. Chem. Phys. 108, 7229 (1998).

  "Complementarity and simultaneous measurement of discrete-valued observables"

Dr. Alexei Trifonov


Department of Microelectronics and Information Technology
Royal Institute of Technology (KTH), Sweden

11:45 AM Monday, April 30, 2001
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Abstract:

True simultaneous measurements of complementary quantum observables are discussed both theoretically and experimentally. The main focus is placed on the observables with a discrete spectrum in addition to the previous theoretical treatment of Arthurs and Kelly.

 Photoassociation of quantum degenerate gases: a shortcut to new matter states

Dr. Matt Mackie


Helsinki Institute of Physics

12:00 noon Monday, June 25, 2001
C-34 Meeting Room
Harvard-Smithsonian Center for Astrophysics

Abstract:

After a brief review of photoassociation as a tool for creating a molecular BEC, we discuss the possbility of forming an atom-molecule Schroedinger cat, as well as photoassociation-induced Cooper pairing in a Fermi gas.

 "Breit interaction correction to the hyperfine constant of an external s-electron in many-electron atom"

Prof. Oleg Sushkov


University of New South Wales, Australia

12:00 PM Wednesday, November 14, 2001
Pratt Conference Room
Harvard-Smithsonian Center for Astrophysics

Abstract:
Correction to the hyperfine constant $A$ of an external s-electron in many-electron atom caused by the Breit interaction is calculated analytically: $\delta A/A =0.68 Z\alpha^2$. Physical mechanism for this correction is polarization of the internal electronic shells (mainly $1s^2$ shell) by the magnetic field of the external electron. This mechanism is similar to the polarization of vacuum considered by Karplus and Klein long time ago. The similarity is the reason why in both cases (Dirac sea polarization and internal atomic shells polarization) the corrections have the same dependence on the nuclear charge and fine structure constant.

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