Experimental Atomic Physics

Isaac Abella

Ph.D., Columbia, 1963.
Professor Emeritus, Dept. of Physics and the College.
Experimental atomic physics, quantum optics, laser spectroscopy.

Laser Coherent Transients. Photon echo techniques are used to probe metastable excited states in rare gas mixtures such as helium, neon, and argon. The states are produced in a weakly ionized r.f. plasma discharge, and nitrogen-pumped dye lasers are used to generate the coherent super-position states.

Spectroscopy of Rare-Earth Laser Material. Samples of YLF and YAG crystals doped with erbium, thulium, and holmium are being studied with selective laser excitation in the region of 780 nm, the erbium bands. These materials can be efficiently optically pumped by the AlGaAs-GaAs laser diode arrays, but we are using dye laser excitation. We are interested in the energy transfer process: Er to Tm, to Ho, which concentrates energy emission at 2.085 microns at room temperature and at liquid nitrogen. The process is a radiationless, almost resonant transfer of energy between sites and depends on the relative concentrations of the rare earth ions. In particular we are interested in measuring decay rates, excited state absorption, and branching ratios and detailed theories of such processes.

: Professor Abella (second from the right) joined other founding fathers of the laser at the Berkeley Laserfest 2010. Pictured here from left to right are: Joseph Giordmaine, Arno Penzias, Gene Serabyn, Everett Lipmann, Samuel Gasster, Jonathan Weiner, Charlie Townes, John J. Ottusch, Isaac Abella, and Aniruddha Das.

Selected Publications:

  • National Science Education Standards. Report of National Research Council, National Academy of Sciences. I.D. Abella, member of Science Content Standards, National Academy Press, Washington DC, 1996.
  • “Radio Waves. Radar”. I. D. Abella. In Macmillan Encyclopedia of Physics, Macmillan Press, New York, 1996.
  • "Science Teaching Reconsidered" report of National Research Council, National Academy of Sciences, I. D. Abella, member of Committee on Undergraduate Science Education (CUSE), (National Academy Press, Washington, D.C. 1997).
  • "Transforming Undergraduate Education in Science..." Report of National Reseach Council, National Academy of Sciences, I. D. Abella, member of Committee on Undergraduate Science Education (CUSE), (National Academy Press, Washington, D.C. 1999).
  • "Laser History at Columbia University", I. D. Abella, Physics Today, p 8-10, May 2010
  • "Columbia Radiation Lab, circa 1960", I. D. Abella, Paper presented at Cummins Memorial Symposium, City University of New York, October 30, 2010.

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Updated 2/2011

Cheng Chin Cheng Chin

Ph.D., Stanford University, 2001.
Professor, Department of Physics, James Franck Institute, Enrico Fermi Institute, and the College.
Laser cooling and trapping, degenerage quantum gases.
Cheng Chin's homepage

Bose-Einstein condensation of molecules and Fermionic superfluids. The formation and condensation of composite bosons by pairing fermionic atoms open the door to the exploration of superfluidity in different regimes. In the strong-coupling limit, atoms form short-ranged molecules, which undergo Bose-Einstein condensation (BEC) at low temperatures. In the weak-coupling regime, Cooper-pairing of atoms occurs in the Bardeen-Cooper-Schrieffer (BCS) state. In the crossover regime, the two types of superfluid smoothly connect to a new type of resonance superfluid, for which a universal behaviour is predicted.

Scalable quantum manipulation and quantum computation. Computation in the realm of quantum mechanics can be exponentially faster than its classical counterpart. In spite of the abundance of proposals to implement quantum computation, few systems have been experimentally demonstrated or can in principle be scalable to many quantum bits (qubits).

Ultracold atoms in an optical lattice formed by optical standing waves are a promising system to realize a scalable quantum computation system. By tuning the relative phase of the standing waves, arbitrary two atoms can be entangled by bringing them into close spatial vicinity. Repeating the above entanglement process on different atom pairs, we can establish quantum entanglement of many atoms. Since atoms can be individually trapped in the lattice with a typical periodicity of the optical wavelength, many qubits can be stored within a small volume of several cubic microns.

Selected Publications:

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Updated 04/2013

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Zheng-Tian Lu Zheng-Tian Lu

Ph.D., University of California at Berkeley, 1994.
Senior Physicist, Physics Division, Argonne National Laboratory. Professor (part time), Department of Physics and Enrico Fermi Institute and the College.
Experimental physics, atomic physics.

Zheng-Tian Lu's homepage

Testing time-reversal symmetry in atoms and nuclei. We are searching for a permanent electric-dipole moment (EDM) of the 225Ra atom (t1/2 = 15 d). A positive finding would signify the violation of time-reversal symmetry. This experiment provides an outstanding opportunity to search for new physics beyond the Standard Model. We have succeeded in realizing laser trapping and cooling of radium atoms (both 226Ra and 225Ra). At present, we are developing the techniques and apparatus needed for the EDM measurements with cold 225Ra atoms. See AIP News 812-3 (2007).

Radio-krypton dating. The Atom Trap Trace Analysis (ATTA) method has revolutionized our ability to measure radiokrypton isotopes, 81Kr (t1/2 = 229,000 yr) and 85Kr (t1/2 = 10.8 yr), in samples of natural material. This in turn opens the door to a wide range of new applications in the Earth sciences. 81Kr measurements of groundwater samples from the Nubian Aquifer in the Western Desert of Egypt showed residence times approaching one million years. At present, we are developing the next generation instrument, ATTA-3, which is expected to further reduce sample sizes required for radiokrypton analyses of groundwater and glacial ice. See AIP News 679-3 (2004).

Studying exotic nuclear structure. Helium-8 (8He) is the most neutron-rich matter that can be synthesized on earth: it consists of two protons and six neutrons, and remains stable for an average of 0.2 seconds. Because of its intriguing properties, 8He has the potential to reveal new aspects of the fundamental forces among the constituent nucleons. We have recently succeeded in laser trapping and cooling this exotic helium isotope and have performed precision laser spectroscopy on individual trapped atoms. Based on atomic frequency differences measured along the isotope chain 3He-4He-6He-8He, the nuclear charge radius of 8He has been determined for the first time. The result can now be compared with the values predicted by a number of nuclear structure calculations and is testing their ability to characterize this loosely-bound halo nucleus. See AIP News 851-2 (2007).

Selected Publications:

  • Nuclear charge radius of He-8. P. Mueller et al., Phys. Rev. Lett. 99, 252501 (2007).
  • Laser-trapping of Ra-225 and Ra-226 with repumping by room-temperature blackbody radiation. J. R. Guest et al. Phys. Rev. Lett. 98, 093001 (2007).
  • Laser spectroscopic determination of the 6He nuclear charge radius. L.-B. Wang et al. Phys. Rev. Lett., 93, 142501 (2004).
  • Tracing Noble Gas Radionuclides in the Environment. P. Collon, W. Kutschera and Z.-T. Lu., Ann. Rev. Nucl. Part. Sci., Vol. 54, 39 (2004). Nucl-ex/0402013.
  • Search for anomalously heavy isotopes of helium in the Earth’s atmosphere. P. Mueller et al. Phys. Rev. Lett. 92, 022501 (2004).

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Updated 1/2008

jonathan Jonathan Simon

Ph.D., Harvard University, 2010.
Neubauer Family Assistant Professor, Department of Physics and James Franck Institute and the College
Quantum manybody physics, ultracold atomic gases.

Jonathan Simon's homepage

My research interests span condensed matter physics, quantum optics, and atomic physics. A consistent theme in my work is the effort to understand how the wonderfully bizarre laws of quantum mechanics imbue materials with exotic properties. This is important both technologically and fundamentally, as emergent physics in strongly interacting quantum systems is truly the wild west of modern condensed matter physics.

The tools of atomic physics provide an exciting new route to building and understanding quantum materials. Honed through decades of precision measurement work, these tools offer extraordinary control of laser-cooled atoms and deep understanding of how such atoms interact with one another. My work employs this approach to build designer synthetic materials from cold atoms and probe their properties at the level of individual quantum particles.

Building quantum systems from the ground up provides a wonderful opportunity to move from the simpler, few-body realm of quantum optics to the exquisite challenges of many-body quantum theory. This complements the more traditional route in condensed matter, where the underlying microscopic physics and emergent behaviors must both be teased from observations.

In the laboratory, I study ultracold atoms in optical lattices and strongly interacting photonic quasi-particles called Rydberg polaritons, emphasizing single-particle readout and manipulation. Exploring how quantum systems organize and respond to external stimuli will provide inspiration for the next generation of quantum devices and a deeper understanding of phenomena from high temperature superconductivity to topological ordering.

Selected Publications:

  • Waseem S. Bakr, Philipp M. Preiss, M. Eric Tai, Ruichao Ma, Jonathan Simon, Markus Greiner, Orbital excitation blockade and algorithmic cooling in quantum gases. Nature 480, 500-503 (2011).
  • Haruka Tanji-Suzuki, Wenlan Chen, Renate Landig, Jonathan Simon, Vladan Vuletic, Vacuum Induced Transparency. Science 333, 1266-1269 (2011).
  • Jonathan Simon, Waseem S. Bakr, Ruichao Ma, M. Eric Tai, Philipp M. Preiss, Markus Greiner, Quan- tum Simulation of Antiferromagnetic Spin Chains in an Optical Lattice. Nature 472, 307-312 (2011).
  • Waseem S. Bakr, Amy Peng, M. Eric Tai, Ruichao Ma, Jonathan Simon, Jonathon Gillen, Simon Fo ̈lling, Lode Pollet, Markus Greiner, Probing the Superfluid-to-Mott-Insulator Transition at the Single- Atom Level. Science 329, 547-550 (2010).

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Updated 9/2012

linda Linda Young

Ph.D., California, Berkeley, 1981.
Distinguished Fellow, Argonne National Laboratory
Professor (part-time), Department of Physics and James Franck Institute and the College
Atomic physics, x-ray physics.

Nonlinear x-ray interactions: The advent of hard x-ray free electron lasers (XFELs) in 2009 inaugurated exploration of a new regime of high-intensity, short-wavelength photon / matter interactions. Intensities approaching 1020 W/cm2 are now available at Ångstrom wavelengths with associated field strengths that exceed the atomic value by a factor of 1000. XFEL peak intensities exceed those available at synchrotron sources by nine orders of magnitude and thus require a new framework for understanding radiation-matter interactions. We aspire to a quantitative understanding of complexity in this highly nonlinear regime by combining experiment at XFELs and theory/simulation using high performance computing.

Controlling inner-shell electron dynamics: Newly developed control of XFEL pulses providing longitudinal coherence via seeding methods, in combination with two-color x-ray pump/x-ray probe schemes, offer significant opportunities to understand x-ray induced processes, such as stimulated Raman scattering and Rabi flopping. X-ray pump/x-ray probe techniques can be used to observe the competition between hole migration to other atomic sites, Auger decay into valence holes and molecular dissociation. Observations in carefully selected systems can shed light on, e.g., the phenomenon of atomic-site-selective bond scission, as a step toward the overall understanding of the fundamentals of x-ray damage.

Coherent ultrafast x-ray imaging and spectroscopy: Observation of ultrafast molecular motions with atomic resolution is becoming feasible with coherent x-ray pulses that provide elemental, chemical and spin contrast. Since these studies rely on linear x-ray absorption and scattering, one can track behavior over multiple timescales using both synchrotrons and XFELs. We are interested in developing optical “pump” control sequences to steer processes in condensed phases with x-ray feedback.

Selected Publications:

  • Theoretical Tracking of Resonance-Enhanced Multiple Ionization Pathways in X-ray Free-Electron Laser Pulses, P. J. Ho, C. Bostedt, S. Schorb and L. Young, Phys. Rev. Lett113, 253001 (2014).
  • Unveiling and Driving Hidden Resonances with High-Fluence, High-Intensity X-Ray Pulses, E. P. Kanter et al., Phys. Rev. Lett. 107, 233001 (2011).
  • Femtosecond electronic response of atoms to ultra-intense X-rays, L. Young et al., Nature 466, 56 (2010).
  • Controlling X-rays with light, T. E. Glover et al., Nature Physics 6, 69 (2010).
  • Electromagnetically induced transparency for x-rays, C. Buth, R. Santra, L. Young, Phys. Rev. Lett.98, 253001 (2007).
  • Development of high-repetition-rate laser pump/x-ray probe methodologies for synchrotron facilities, A. M. March et al., Rev. Sci. Instr. 82, 073110 (2011).

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Updated 5/2016

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