• Theoretical Condensed-Matter Physics
• Theoretical Elementary Particle Physics
• Astrophysics and General Relativity
• Experimental Elementary Particle Physics
• Accelerator Physics
• Experimental Condensed-Matter Physics
• Biological Physics
• Multidisciplinary Research
• Major Research Facilities
• Resources for Researchers

B.S., 1973, Illinois Institute of Technology. M.S., 1977, Cornell University. Ph.D., 1979, Cornell University. Post-Doctoral Research Associate, Cornell University , 1978-79. Assistant Professor, Physics, Texas A & M, 1979-84. Associate Professor, Physics, Texas A & M, 1984-86. Associate Professor, Physics, Cornell, 1986-93. Professor, Physics, Cornell, 1993-present. Visiting appointments at: Walther-Meissner Institut fur Tieftemperaturforschung; Royal Holloway, University of London. Alfred P. Sloan Fellow, 1982-86. John Simon Guggenheim Fellow, 1994-95.

Research Areas

Low temperature physics, including the physics of superfluid 3He; mixtures of 3He and 4He; disordered superfluids; glass at low temperatures, micro- and nano-mechanical resonators, their design, optimization, and non-linear characteristics

Current Research

The study of superfluid 3He in aerogel: We use high Q oscillators to look for phase transitions and assay the superfluid fraction of 3He in aerogel in the millikelvin temperature range. We are exploring the A-B transition, effects of magnetic field to probe the nature of the superfluid as well as uniaxial compression to "orient" the superfluid order parameter. We have also built (and are testing) a micromachined cell to probe superfuid 3He in the "2D" limit, where the superfluid is confined between two silicon surfaces separated by distances on the order of a few coherence lengths. Other topics under active investigation are the elastic properties of glasses (particularly silicon nitride under stress) at low temperatures, dielectric properties of glasses and also the heat capacity and thermal conductivity of high stress silicon nitride.
Nanomechanical systems: A second area of interest is concerned with applications and innovations with nano-electromechanical devices. This work is carried out in collaboration with Harold Craighead (A&EP) and is also supported by Analog Devices. In this work we will explore and optimize the operational characteristics of NEMS/MEMS devices in ambient conditions, as well as integrate devices to CMOS circuitry in a generic process to facilitate their adoption in future applications and seek to apply these devices to sensing.
Graphene: A third (developing) area of interest is in the use of graphene to separate diverse environments (eg vacuum/air). The mechanical properties of the membrane can provide insight into the state of the confined system - ie pressure, diffusion, phase transitions. This work is being carried out in collaboration with the McEuen and Craighead groups.

Postdocs
Josh Cross and Rob Bennett

Research Associates
Eric Smith and Maxim Zalalutdinov (based at the Naval Research Labs)

Graduate Students
Darren Southworth 

Spotlight

Jalina Keeling is an undergraduate student with the Itai Cohen Group on Complex Matter Physics (who is at Cornell as part of the NSF's Research Experiences for Undergraduates program). She is conducting experiments similar to the epitaxial growth of crystals, but using polymer beads. She uses a confocal microscope to scan a sample of these beads from bottom to top. Her research seeks to answer the questions "What structures form? How do we tune the concentration of polymers to change ...
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