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Unformatted text preview: Problem set 6, Due March 7 1 Calculate the specific heat (at constant density) and the linear magnetic suscetibility of a free elecron gas of constant density in the low temperature limit. For simplicity, assume that the electronic density of states is g ( ) = a 1 / 2 , and keep only the first nonvanishing term in the low temperature expansion. Explicitely account for the temperature dependence of the chemical potential in each case. How good was the approximation, made in class, of ignoring the temperature dependence of ? (The following (Somerfeld) expansion of the fermi function may be useful f ( ) ( - )- 2 6 ( k B T ) 2 ( - ).) 2 First Sound. Sound can propagate in a Fermi Liquid in two ways. If is the scattering lifetime (1 / the scattering rate), then clearly when 1 / no sound will propagate since the excitations are not sufficiently long lived. However, is a function of temperature. Thus, at high temperatures is small, and sound will propagate more-or-less normally. As the temperature is lowered, whensmall, and sound will propagate more-or-less normally....
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This note was uploaded on 01/10/2012 for the course PHYSICS 707 taught by Professor Electrodynamics during the Fall '11 term at LSU.
- Fall '11