3/9/2006 Physics Colloquium: Moses H. W. Chan

[Rosrin Srethapramote <rosrin MIT EDU>]

Physics Colloquium Series at MIT
3/9/2006

Moses H. W. Chan , Penn State University
Superfluidity in solid helium and solid hydrogen

Recent torsional oscillator measurements of solid helium confined in porous media [1,2] and in bulk form [3] found evidence of non-classical rotational inertia indicating superfluid behavior below 0.2K. Measurements of solid samples at different pressure (and hence different density) allow us to map out the boundary of this supersolid phase. The low temperature supersolid fraction shows a non-monotonic dependence on pressure. It first increases with pressure reaching a maximum of 1.5% near 55 bars and then decreases with further increase with pressure. We have also obtained preliminary results indicating solid molecular hydrogen also exhibit a similar transition, at a much lower temperature and with a much smaller supersolid fraction. This work is done in collaboration with Eunseong Kim, Tony Clark, Xi Lin and Josh West and it is supported by the (U.S.) National Science Foundation.

1.      E. Kim and M.H.W. Chan, Nature 427, 225 (2004)
2.      E. Kim and M.H.W. Chan, Jour. of Low Temp. Physics, 138, 859 (2005)
3.      E. Kim and M.H.W. Chan, Science 305, 1941(2004).


Time: 4:15pm
Place: Room 10-250
Refreshments will be served in the Physics Undergraduate Lounge (8-329) at 3:45pm

For a complete list of upcoming colloquia, please visit the Physics website:   http://web.mit.edu/physics/newsandevents/physics_colloquia_sched_spring_06.html