Controlling the Quantum World: The Science of Atoms, Molecules, and Photons (2007)

New modalities for doing science arise as a means of doing science more effectively. The best ones arise naturally, following the needs of the science. One particularly important reason for collaboration is the increasingly interdisciplinary nature of the work being done throughout science. Another reason is the availability of large-scale facilities (synchrotron light sources, high-intensity lasers, specialized laboratories), which provide unique access to specialized instrumentation and expertise. Yet another is the value of assembling a critical mass of people to work on closely related topics.

The Multidisciplinary University Research Initiative (MURI) concept is unique to the DOD funding agencies (AFOSR, ARO, DARPA, and ONR). These 5-year awards of $1 million per year are intended to advance the necessary research in a university environment. They are in wide use.

As described in Appendix D, the AFOSR supports one MURI effort in laser diagnostics. It supports no other centers.

A substantial fraction (60–70 percent) of ARO funding goes into centers whose topics of study have changed over the decade. Recently MURI centers have been studying quantum imaging (employing entanglement to perform nonclassical imaging, including subwavelength resolution, ghost imaging, quantum radar, pixel entanglement, and so on); atom optics (quantum degenerate gases such as Bose condensates, atom lasers, and the like, and guiding them in free space and on chips, performing interferometry, and so on); and quantum information and computing (exploiting quantum entanglement in ion traps, optical lattices, molecules, and so on for making qubits, teleporting information, transferring coherence between entities as in from photons to degenerate gases and back, cavity QED implementations, etc.). Quantum information and computing has seen numerous MURIs come and go. The Army also supports a small in-house optics center (not a MURI) at West Point.

DARPA is unique in DOD in that it does not maintain an infrastructure of laboratories or research facilities. This allows it to minimize institutional interests that would otherwise distract it from its search for new research areas and world-class performers. DARPA does not necessarily seek to advance progress in established disciplines, but instead will bring together teams from diverse institutions and disciplines to solve a particular problem. In the past, this was sometimes done through the establishment and funding of interdisciplinary laboratories. More recently, DARPA has been funding interdisciplinary teams of researchers from multiple research institutions without establishing a fixed infrastructure. Currently, DARPA does not operate or fund any centers in AMO science, though it funds major AMO-related collaborations.

The ONR presently supports three MURI awards at $ 1 million per year each. Two are in optical frequency standards and atomic clocks, while the third studies sub-shot-noise measurement using quantum control.

The AMO science program supports five large group efforts. Four are at DOE national laboratories and one is at Kansas State University. The levels quoted

are the FY2005 allocations. Yet another—the Photon Ultrafast Laser Science and Engineering (PULSE) program at Stanford—is supported from the BES Materials Science Program.

• J.R. Macdonald Laboratory Program for Atomic, Molecular, and Optical Physics at Kansas State ($2.5 million per year). This laboratory combines theory and experiment to investigate dynamical processes involving ions, atoms, molecules, surfaces, and nanostructures exposed to short, intense bursts of electromagnetic radiation. Current efforts are focused on time-resolved dynamics of heavy-particle motion in single molecules and molecular ions; coherent excitation and control in multilevel systems; interaction of intense short-pulse laser radiation and ions with surfaces and nanostructures; at-tosecond science (in particular using real-time probes of the electronic wave function); and collisions with highly charged ions.

• Multiparticle processes and interfacial interactions in nanoscale systems built from nanocrystal quantum dots at Los Alamos ($0.8 million per year beginning in 2002). This research is aimed at controlling the functionalities of nanomaterials. It requires a comprehensive physical understanding at different levels, ranging from individual nanoscale building blocks to the complex interactions in the nanostructures built from them. This project concentrates on electronic properties of semiconductor quantum-confined nanocrystals and the electronic and photonic interactions of assemblies of them. The group studies multiparticle processes in individual nanocrystals and interfacial interactions. The ability to understand and control both multiparticle processes and interfacial interactions could lead to such new technologies as solid-state optical amplifiers and lasers, nonlinear optical switches, and electrically pumped, tunable light emitters.

• Atomic and Molecular Physics Group at Oak Ridge National Laboratory (ORNL) ($1.8 million per year). The goal is the understanding and control of interactions and states of atomic-scale matter. The objective is to develop a detailed understanding of the interactions of multicharged ions, charged and neutral molecules, and atoms with electrons, atoms, ions, surfaces, and solids. Toward this end, a robust experimental program is carried out at the ORNL Multicharged Ion Research Facility and as needed at other facilities. Closely coordinated theoretical activities support this work, as well as lead investigations in complementary research. Specific focus areas for the program are broadly classified as particle-surface interactions, atomic processes in plasmas, and manipulation and control of atoms, molecules, and clusters.

• Atomic, Molecular and Optical Sciences Group at Lawrence Berkeley National Laboratory ($1.365 million per year). This program is aimed at understand-

ing the structure and dynamics of atoms and molecules using photons and electrons as probes. The current emphasis is in three major areas with important connections and overlap: inner-shell photoionization and multiple ionization of atoms and small molecules; low-energy electron impact and dissociative electron attachment of molecules; and time-resolved studies of atomic processes using a combination of femtosecond x rays and femtosecond laser pulses. The goal of the ultrafast science effort is to probe fundamental atomic and molecular processes involving femtosecond (and ultimately attosecond) x rays interacting with atoms and molecules in the presence of laser fields and to shed light on electron correlations within these systems.

• Atomic, Molecular, and Optical Physics Group at Argonne National Laboratory ($1.215 million per year). The central goal is to establish a quantitative understanding of x-ray interactions with free atoms and molecules. With the advent of hard x-ray free electron lasers, exploration of nonlinear and strong-field phenomena in the hard x-ray regime becomes possible. Techniques for microfocusing x rays are being developed to help understand the behavior of atoms and molecules in strong optical fields. These studies of atoms and molecules in strong optical fields will be relevant for pump-probe experiments at next-generation sources. Foundational to these experiments is the detailed understanding of x-ray photoionization. The group has focused on the limitations of our current theoretical understandings.

• The Photon Ultrafast Laser Science and Engineering Center at SLAC. The Stanford PULSE Center conducts interdisciplinary research in ultrafast science. PULSE has a major AMO component, although in 2005 it was funded from the Materials Science program in DOE. A major AMO focus of this center is research at the LCLS x-ray free-electron laser, specifically on the interaction of atoms and molecules with high-field and ultrafast short-wavelength radiation and on the control of quantum dynamics in atoms and molecules at attosecond to femtosecond timescales.

NIST supports six divisions at its Gaithersburg and Boulder sites in which AMO science plays a lead role. Some of the funding for these laboratories comes from other federal sources (for example, DOD and NASA). Relatively new areas of AMO competence, with total funding levels, are these:

• Quantum information/quantum computing/quantum communication ($9 million per year).

• The Center for Nanoscale Science and Technology (CNST) user’s facility, located within the new NIST Advanced Measurement Laboratory (500,000 ft², featuring a 90,000 ft² clean room facility, built at a cost of $200 million). The annual budget for CNST is about $6 million.

• Molecular measurement and manipulation (about $1 million per year, aimed at bioscience).

• Low-temperature quantum coherence, including laser cooling and trapping, Bose-Einstein and Fermi condensation, atomic fountain clocks, trapped ion optical clocks (about $7 million per year).

NSF’s Mathematical and Physical Sciences Division supports four centers in AMO science. The funding levels quoted below are the FY2005 allocations.

• Center for Ultracold Atoms (CUA) ($1.5 million per year beginning in FY2000). CUA is funded through the AMOP program in the Physics Division and the Condensed Matter Physics program in the Division of Materials Research. In FY2005, it was transferred to the Physics Frontiers Centers program for award management and future competition. CUA brings together a community of scientists from the Massachusetts Institute of Technology and Harvard University to pursue research in the new fields. The core research program consists of four collaborative experimental projects whose goals are to provide new sources of ultracold atoms and quantum gases and new types of atom-wave devices. These projects will enable new research on topics such as quantum fluids, atom/photon optics, coherence, spectroscopy, ultracold collisions, and quantum devices. In addition, the CUA has a theoretical program centered on quantum optics, many-body physics, wave physics, and atomic structure and interactions.

• Frontiers in Optical Coherent and Ultrafast Science (Physics Frontier Center, $15 million over 5 years beginning in 2001). The FOCUS mission is to provide national leadership in the areas of coherent control, ultrafast physics, and high-field physics. FOCUS will extend the frontiers of the discipline: the production, control, and utilization of subpicosecond and, eventually, subfemtosecond pulses; coherent manipulation of molecular bonds and intramolecular dynamics; physics of ultrahigh laser fields (luminosity >10²⁰W/cm²); and control of entanglement in ultracold atoms and ions. The coherent field strengths under direct control will span 18 orders of magnitude, from ultrarelativistic, laser-driven plasmas (teravolts per centimeter) to control fields in cooled ion traps (millivolts per centimeter).

Laser-driven particle energies will range from GeV to neV. Much of the coherent control physics developed in one area is applicable to other areas.

• JILA (jointly supported with NIST; $3.2 million from NSF in 2005). Although the majority of its funding comes from NIST, NSF’s AMOP program provides an amount of funding comparable to that for any of its other large centers. NSF will begin to treat JILA in the same category as FOCUS and CUA starting in the 2006 renewal cycle.

• Institute for Theoretical Atomic, Molecular and Optical Physics (ITAMP; Harvard-Smithsonian Center for Astrophysics and the Harvard University Physics Department; $0.65 million per year, begun in 1988). Though not funded as a “center” by NSF, it functions as one as far as the theoretical AMO community is concerned. It has very active postdoctoral and visitor programs, a constantly changing menu of active theoretical topics, a lively series of workshops and an excellent computation center. It prospers significantly from its close ties to the Harvard-Smithsonian Center for Astrophysics.

• Engineering Research Center for Extreme Ultraviolet Science and Technology (Colorado State University, University of Colorado at Boulder, University of California at Berkeley, and Lawrence Berkeley National Laboratory). Funded by the NSF’s Directorate for Engineering, the initial award ($17 million over 5 years beginning in October 2003) supports the first 5 years of a 10-year cooperative agreement. The goal of the center is to confront a variety of challenging scientific and industrial problems by using short-wavelength light in the extreme ultraviolet (EUV) range of the electromagnetic spectrum. The researchers are exploring the interface of physics, electrical engineering, chemistry, and biology using high-energy, extremely short-wavelength, coherent EUV light.

Over the past two decades, AMO science has played an important role in the development of very intense synchrotron light sources¹ that have been indispensable not only to AMO researchers but also to workers in materials science, condensed matter physics, and biology. In the United States, the forefront laboratories are these:

• Advanced Photon Source at Argonne National Laboratory, Illinois (third-generation x-ray source).²

• Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory, California (third-generation soft x-ray source).

• Cornell High Energy Synchrotron Source at Cornell University, Ithaca, New York (third-generation x-ray source).

• National Synchrotron Light Source (NSLS) at Brookhaven, New York (second-generation VUV and x-ray source).

• Stanford Synchrotron Radiation Laboratory’s Stanford Positron Electron Accelerating Ring at Menlo Park, California (third-generation x-ray source).

Other smaller facilities in the United States are these:

• Center for Advanced Microstructures and Devices, Baton Rouge, Louisiana (second-generation soft x-ray source).

• Duke Free Electron Laser Laboratory, Durham, North Carolina (fourth-generation infrared source).

• Jefferson Laboratory Free Electron Laser, Newport News, Virginia (fourth-generation infrared source).

• Synchrotron Radiation Center, Madison, Wisconsin (third-generation VUV source).

• Synchrotron Ultraviolet Radiation Facilty, NIST, Gaithersburg, Maryland (second-generation VUV source).

• UCSB Center for Terahertz Science and Technology, Santa Barbara, California (fourth-generation far-infrared source).

• W.M.Keck Free Electron Laser Center at Vanderbilt University, Nashville, Tennessee (fourth-generation mid-infrared source).

The fourth generation of x-ray light sources will not be synchrotrons at all but will be built around the concept of the free-electron laser³ using linear accelerators. Worldwide there is very substantial R&D work in progress in this area (see Appendix C).

The LCLS, a $379 million facility, will be the world’s first x-ray free-electron laser facility for science when it becomes operational in 2009. Construction started

in FY2005. Pulses of x-ray laser light from LCLS will be many orders of magnitude brighter and several orders of magnitude shorter than what can be produced by any other x-ray source available now or in the near future. These characteristics will enable frontier new science in areas such as discovering and probing new states of matter, understanding and following chemical reactions and biological processes in real time, imaging chemical and structural properties of materials on the nanoscale, and imaging noncrystalline biological materials at atomic resolution. The LCLS project is funded by the DOE/BES and is a collaboration of six national laboratories and universities.

There are also a number of large-scale laser facilities with strong links to AMO, built here and abroad (see Appendix C).

• OMEGA at the Rochester Laboratory for Laser Energetics. This facility is the highest energy laser working in the United States. DOE operates OMEGA primarily for work related to laser fusion. University researchers are also eligible to apply for shots on OMEGA.

• JANUSP at the Lawrence Livermore National Laboratory. This facility is used for high-field laser-atom and laser-plasma physics by scientists at universities as well as the national laboratories.

• National Ignition Facility (NIF). When completed, NIF at the Lawrence Livermore National Laboratory will be the nation’s most powerful laser, supporting DOE’s National Nuclear Security Administration defense program’s mission to verify the safety and reliability of U.S. nuclear weapons. NIF will also study inertial confinement fusion for energy.

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