Overview

The objective of the Physics Program of the Army Research Office is to develop forefront concepts and approaches, particularly exploiting atomic-scale and quantum phenomena, which will in the long-term have revolutionary consequences for Army capabilities, while in the mid-term providing for Army needs. In support of this goal, the interests of the Physics Division are primarily in the following areas:

• Condensed Matter Physics
• Statistical Mechanics and Nonlinear Dynamics
• Quantum Information Science
• Atomic and Molecular Physics
• Optical Physics and Image Science

There is little direct interest in Relativity and Gravitation, Cosmology, Elementary Particles and Fields, Nuclear Physics, Astronomy, or Astrophysics, since they generally have little impact on the areas of Army needs. Nevertheless, the possible relevance of topics within these other physics disciplines is not absolutely discounted, and discussions of potential exceptions are welcome.

The disciplinary boundaries of the ARO are not sharply drawn as shown by the joint support of a number of efforts by the Physics Division and other ARO Divisions. In addition, it is not necessary that a potential investigator be associated with a Physics Department to receive support from the Physics Division.

1.1. Condensed Matter Physics

Condensed Matter Physics (CMP) is a foundational science enabling fundamental Army technologies in areas such as information processing, communications, sensors, optical components, electronics, optoelectronics, night vision, seekers, countermeasures, and many others. Technologies such as these would not exist today, at least not as we know them, without visionary research in the field of CMP. The ARO CMP workpackage strives to continue this level of impact by looking beyond the current understanding of natural and designed condensed matter, to lay a foundation for revolutionary technology development for next generation and future generations of warfighters. Areas of future impact include novel computational components and architectures, novel electronic and optoelectronic devices and ones with higher efficiencies and significantly lower weight, and secure communications and sensing technologies.

1.1.1. Nanometer-Scale Physics

The CMP program is interested in the investigation of physical phenomena operative in nanometer-sized materials. The objective is twofold: to investigate and control nanoscale phenomena in well-defined nanometer-sized environments, and to elucidate how these phenomena are modified and may be exploited when such nanostructures are assembled into novel composite materials or device structures. Related interests include collective and cooperative nanoscale phenomena, understanding the evolution of atomic to nanoscale to bulk behavior, and phenomena at surfaces and interfaces.

1.1.2. Physics of Infrared Devices

Prolific engineering efforts to develop infrared devices have pushed the limits of performance, and have underscored the need to understand the physical processes involved in these device structures. Processes of interest are the coupling of carrier transport to the electromagnetic field modes within the device structure, nonlinearities, and collective effects. Expanding design space beyond band structure engineering, which controls the carrier transport, to include photonic or plasmonic engineering, which can control the electromagnetic field, is also of interest. Both theoretical studies and experimental investigations that link carrier transport, device structure, and materials growth and processing conditions are required.

1.1.3. Strong Correlations and Novel Quantum Phases of Matter

Discovering, understanding, and experimentally demonstrating novel phases of matter in strongly correlated systems will lay a foundation for new technology paradigms for applications ranging from information processing to sensing. Interest includes strong correlations of electrons as well as of other particles or excitations. Material systems of interest range from complex oxides, to two dimensional electron gas systems, to synthetic assemblies simulating both real materials and lattice models. The program seeks to foster novel ideas targeting the discovery of new quantum phases of matter, and how excitations within these phases can be probed and controlled.

1.1.4.  Unique Instrumentation Development

Advanced studies of CMP phenomena will often require unique experimental techniques that are not readily available. The construction and demonstration of new methods for probing and controlling unique phenomena, especially in the studies of novel quantum phases of matter, is of particular interest. Further, structures and assemblies exhibiting unique CMP phenomena may require unique synthesis techniques, which might range from biological assembly to optical lattices. Establishing such techniques for the fabrication or simulation of condensed-matter systems are of interest when they provide access to novel quantum phenomena which are not otherwise readily obtainable.

Technical Point of Contact: Dr. Marc Ulrich, e-mail: Marc.Ulrich@us.army.mil , (919) 549-4319.

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1.3. Atomic and Molecular Physics

Research in atomic and molecular physics will create fundamentally new capabilities for the Army, as well as providing the scientific underpinnings to enhance existing technologies. Topics of interest include quantum degenerate atomic gasses, both Bose and Fermi, their excitations and properties, including mixed species, mixed state, and molecular; matter-wave optics and matter-wave lasers; nonlinear atomic and molecular processes; quantum control; novel forms and effects of coherence; and emerging areas. Cooling schemes for molecules are of importance for extending the range of systems that may be exploited. Applications range from ultra-sensitive detectors including improved inertial sensors and navigation aides; to sensor protection; to novel sources. In addition, areas of application include novel materials processing, e.g., by obtaining increasingly complex molecules, clusters, or patterned structures, perhaps from something like matter-wave holography, or through quantum control.

1.3.1. Matter-Wave Optics

Matter waves offer new or enhanced capabilities in a number of areas. For example, cooling, trapping and coherent control of atoms and molecules may provide ultra-sensitive sensors, including gyroscopes for inertial navigation, or ultra-high resolution lithography. In addition to the sensitivity advantage of matter waves, they also have additional degrees of freedom such as mass and associated "external" quantum states (together with a richer internal state structure) that might provide handles for new sensing capabilities. The use of coherent matter waves and Bose condensates (e.g., as in a "matter-wave laser") requires basic research to better understand issues such a coherence and decoherence, trapping and out-coupling techniques, and "matter-wave optics" to collimate, diffract, split, combine, interfere and otherwise manipulate matter waves. Laser cooling and trapping of atoms and molecules also may provide proof of principle demonstrations of key components of quantum computing.

1.3.2. Molecular Physics

The molecular physics program is distinguished from programs in chemistry and in materials science. One distinguishing feature is its focus not on synthesis, but on the underlying mechanisms, such as electronic transport, magnetic response, coherence properties (or their use in molecule formation/selection), and/or linear and nonlinear optical properties. The systems of interest are well-defined molecules, generally small or of high symmetry, and their functionalized variants. The objective is to broaden the scope of atomic physics questions into the molecular regime. Cooling, trapping, and Bose condensing molecules fall into this scope. Coherent atomic-molecular superposition states, a novel form of matter, are another example. The ability to use Feshbach resonances and otherwise tune interactions is also relevant here, both as a mechanism for ultracold molecule production and as a way to cross over from weak coupling to strong coupling limits in superfluidity. Quantum fluids in an optical lattice provide yet more novelty, and offer a forum for investigating open questions in condensed-matter physics.

1.3.3. Fundamental Atomic and Molecular Physics

The Division also has a general interest in exploring fundamental atomic and molecular physics topics that may have an impact on technologies of interest to the Army. For example electromagnetically induced transparency allows propagation of light through a medium that is normally strongly absorbing, and it also provides unique access to nonlinear effects that could lead to very efficient frequency multiplication and tunable sources of electromagnetic radiation. General issues of quantum coherence, quantum interference, and quantum control and their numerous potential applications are also of interest.

Technical Point of Contact: Dr. Peter Reynolds, e-mail: Peter.Reynolds@us.army.mil, (919) 549-4345.

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1.4 Optical Physics and Imaging Science

The Army of the 21st century will rely more on sensing, imaging processing, and autonomous target tracking and recognition than ever before. The objective of this work package is to investigate fundamental physical phenomena that will lead to revolutionary advances in these areas. The Physics Division emphasizes fundamental science that uses photons and their properties (e.g. coherence, wavelength, polarization) in ways that will significantly improve information processing capabilities for the Army in the coming decades. Much like the breakthroughs in integrated electronics that brought revolutionary changes to computing and signal processing, a key objective is to integrate elemental optical components into "integrated optics" or "photonics" for smart, adaptive, reconfigurable sensing and image processing. Another objective is to improve the imaging capabilities of the Army by extending beyond the visible and infrared regions to consider advantages of the THz and ultraviolet regions. The Division has an interest in the identification and resolution of basic research issues that would demonstrate the utility of these approaches.

1.4.2 Unconventional Optics and Imaging

The Division has an interest in extending the capabilities of optical components and systems. Examples of such approaches include hybrid optical/digital systems to minimize classical optics aberrations, and adaptive optics to mitigate atmospheric distortions. Also of potential interest are new approaches to imaging through turbid and scattering media. Several other image-enhancement technologies, such as hyperspectral imaging and infrared polarimetric imaging, having been receiving attention recently. The Division has an interest in the identification and resolution of basic research issues that would demonstrate the utility of these approaches. Also of interest are other approaches that would increase the resolution or contrast of scenes, or otherwise improve the information quality of images.

Technical Point of Contact: Dr. Richard Hammond, e-mail: Richard.Hammond@us.army.mil, (919) 549-4313.

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