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Superfluids and Measurements of Low Temperature Will Richardson Pippa McGuinness Oliver Bibby

Superfluids and Measurements of Low Temperature Will Richardson Pippa McGuinness Oliver Bibby. TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAA. What is a Superfluid?. Normal phases of matter: Gas, Liquid, Solid

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Superfluids and Measurements of Low Temperature Will Richardson Pippa McGuinness Oliver Bibby

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  1. Superfluids and Measurements of Low Temperature Will Richardson Pippa McGuinness Oliver Bibby TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAA

  2. What is a Superfluid? • Normal phases of matter: Gas, Liquid, Solid • At low temperatures Helium does not solidify • Instead we find a new state of matter, Superfluid! • A superfluid has no viscosity and the whole fluid behaves as if it is one. 2.17K

  3. What is Temperature? • Normal fluid fraction (ρN) reduces at temperatures below 2.17K • A Superfluid fraction (ρS) takes its place • The two fractions exist together as a whole, but act independently 2.17K

  4. Resonant Frequency V0eiwt I0eiwt Voltage Response Frequency Vibrating wire resonator 5μm diameter wire D=3mm Resonant frequency, f1 = (1/2π)*(k/m)1/2 where m = effective mass Damping (Δf2) gives resonant width Applying an alternating current results in a Lorentz Force, F =B*I*D The motion of the wire induces a Faraday Voltage, V =(π/4) BD v

  5. Changes in the liquid properties result in changes in the resonance profile, from which we can determine the temperature.

  6. What could we possibly learn from studying superfluid?

  7. Experimental setup Lancaster has world record 3He-4He dilution refrigerators Lowest Temperature in Helium-3 80 μK

  8. Quantum Turbulence Experiments with a Vibrating Grid

  9. Pure Quantum Turbulence

  10. Turbulence Turbulence has enormous scientific and technological implications, but is very poorly understood. Quantum Turbulence may give us new insight …

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