Vito Iaia presented research on observing the superfluid helium-4 transition on multi-walled carbon nanotubes. Superfluid helium-4 is a quantum fluid that exhibits no viscosity or entropy below 2.17 K and its transition temperature changes with the thickness of adsorbed films. The presentation described measuring this transition using a mixing chamber cell and shaker, and showed that applying 225Hz vibrations influenced the transition in a similar way to the original setup, demonstrating more uniform shaking. Future work aims to study thinner helium films and potential quantum phase transitions.

1. Superfluid Helium-4 Transition on
Multi-walled Carbon Nanotubes
Presenter: Vito Iaia
Principal Investigator: Dr. Gary Williams
Mentor: Emin Menachekanian
Department: Physics and Astronomy
4/23/15

2. What is Superfluid Helium-4 ?
 Quantum fluid (below Tλ = 2.17 K)
 No viscosity
 No entropy
 Macroscopic Bose-Coherence
 Adsorbes on top of substrates
 Transition temperature changes
with thinner films
Helium film
adsorbed on surface
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3. What do we Measure?
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4. Main Superfluid setup
Mixing Chamber
Cell
Shaker
Cooling
Capabilities
Limited
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5. Influence of Shaker (225Hz)
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6. Experimental Approach
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Source: W. Robertson , B. Cazzolato and A. Zander, IEEE TRANSACTIONS ON MAGNETICS, 48, No. 9, 2012.

7. Results (225Hz)
Similar results to original setup
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8. Conclusions
 New setup produces same response as old setup
 More uniform vibration across the setup
 Potential for less energy load on mixing chamber
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9. Future Directions
Investigate Thinner Films
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4 5 6

10. Future Directions
Potential Quantum Phase
Transition
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11. Thanks!
 Thanks to Dr. Gary Williams
 Graduate mentor: Emin Menachekanian
 Williams lab: Bob Chen, Andrew Li, Sergey Sushchikh
 UC LEADS
 Questions?
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