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Specific heat of disordered superfluid 3He
1Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
Physical Review Letters
|November 5, 2004
Summary
Disordered superfluid 3He in silica aerogel shows a suppressed specific heat discontinuity at a lower transition temperature. This indicates gapless excitations in the superfluid state, consistent with Ginzburg-Landau theory predictions.
Area of Science:
- Condensed Matter Physics
- Quantum Fluids
- Superfluidity
Background:
- Superfluid 3He exhibits complex phases sensitive to external conditions.
- Disorder in quantum systems can significantly alter thermodynamic properties.
- Understanding these effects is crucial for fundamental physics.
Purpose of the Study:
- To investigate the impact of silica aerogel disorder on the specific heat of superfluid 3He.
- To characterize the thermodynamic transition to superfluidity in a disordered environment.
- To compare experimental findings with theoretical predictions from Ginzburg-Landau theory.
Main Methods:
- Measurement of specific heat in superfluid 3He confined within a silica aerogel matrix.
- Analysis of the thermodynamic transition temperature and the specific heat discontinuity.
- Theoretical modeling using Ginzburg-Landau theory incorporating elastic quasiparticle scattering.
Main Results:
- A sharp discontinuity in specific heat was observed, marking the superfluid transition.
- The transition temperature and the magnitude of the specific heat discontinuity were suppressed compared to bulk 3He.
- Experimental results align with Ginzburg-Landau theory predictions for disorder effects.
Conclusions:
- Silica aerogel disorder reduces the superfluid transition temperature and specific heat discontinuity in 3He.
- Elastic quasiparticle scattering is identified as the mechanism behind these disorder effects.
- The low-temperature specific heat exhibits linear dependence, consistent with gapless excitations on the Fermi surface.