Listening" to the flow of solid 4He"

Seminar

Speaker

Ethan Livne, Technion

Date

15/05/2014 - 15:30Add to Calendar 2014-05-15 15:30:00 2014-05-15 15:30:00 Listening" to the flow of solid 4He" Although solid He does not exhibit bulk supersolidity, there is evidence that grains of solid can move inside a solid matrix. To observe a flow of solid directly, we constructed a "microphone" embedded in solid He contained inside a torsional oscillator. The microphone can detect vibrations down a few percent of a lattice constant. Our idea was that if the solid He flows past the microphone, the atomic corrugation of its surface should generate vibrations at a frequency f = flow speed/lattice constant. We indeed found that solid He can flow while maintaining its solid structure. At our lowest temperature of 0.5K, a frictionless flow of solid was observed, in agreement with the prediction that grain boundaries can be superfluid. Resnick Building 209, room 210 Department of Physics physics.dept@mail.biu.ac.il Asia/Jerusalem public

Place

Resnick Building 209, room 210

Abstract

Although solid He does not exhibit bulk supersolidity, there is evidence that grains of solid can move inside a solid matrix.

To observe a flow of solid directly, we constructed a "microphone" embedded in solid He contained inside a torsional oscillator.

The microphone can detect vibrations down a few percent of a lattice constant.

Our idea was that if the solid He flows past the microphone, the atomic corrugation of its surface should generate vibrations at a

frequency f = flow speed/lattice constant. We indeed found that solid He can flow while maintaining its solid structure.

At our lowest temperature of 0.5K, a frictionless flow of solid was observed, in agreement with the prediction that grain boundaries can be superfluid.