Phase diagrams, 2D Fermi

Question 1

Landau fermi liquid

Answer 1

Question 2

3 types of degenerate fermi liquids in nature

Answer 2

Electrons in metals

Neutron stars

Liquid 3He

Question 3

Electrons in solids versus 3He

Answer 3

Question 4

Phase diagram of 3He vs 4He

Answer 4

Question 5

Clausius-Clapeyron

Answer 5

Question 6

Minimum in 3He melting curve

Answer 6

Question 7

degenerate fermi gas

Answer 7

Its pressure derives almost exclusively from pauli exclusion principle. The temperature that defines this is the Fermi temperature.

Question 8

3He effective mass

Answer 8

Question 9

How well does liquid 3He fit degenerate fermi gas picture?

Answer 9

The answer is, at least on a qualitative level, remarkably well. At sufficiently low temperatures the heat capacity is linear in T, and the magnetic susceptibility is temperature independent (Pauli susceptibility).

Heat capacity c= γT at the lowest temperatures but γ >> γ₀ (ideal gas value)

These enhancements in the low temperature heat capacity are strongly pressure dependent. The effective mass increases with pressure. m*/m increases from 2.8 at p=0 to 5.9 at the melting curve

mag susceptibility χ is also enhanced by this effect, but its enhancement is higher than that of γ . A scaling of density of states in not sufficient to account for both observations It is the interactions between the helium quasiparticles that is responsible for the additional enhancement of χ (see later).