Gas

In General > s.a. Kinetic Theory; matter.
* Idea: A highly compressible fluid, in which the mean interparticle distance is much greater than their size.
@ Statistical mechanics: Rohrmann PhyA(05)cm/04 [new formalism].
> Related topics: see fluctuations.

Ideal Gas > s.a. fluids; specific heat; thermodynamical systems.
* Idea: A large collection of particles with no internal structure, non-interacting except for collisions (small hard spheres).
* Equation of state: The ideal gas law

pV = nRT = Nk_BT ,

where R is the molar gas constant, and k_B the Boltzmann constant (> see constants).
* Remark: Most gases at room T and p behave like ideal gases, but as T → 0 they can't because of quantum effects.
* Internal energy: If s is the number of degrees of freedom (s = 3 for a monatomic gas),

U = (s/2) Nk_BT .

* Entropy: Given by

S = C_V ln(T/T₀) + Nk_B ln(V/V₀) .

* Consequences: Aerosol cans get cold when used.
* In gravitational field: The equilibrium pressure of a perfect gas in a constant gravitational field decreases exponentially with height (barometric formula).
@ Quantum: Meyer qp/97 [quantum lattice gas]; Bloch pw(04)apr [in optical lattices]; Nattermann AJP(05) [scaling approach]; Velenich et al JPA(08) [Brownian gas, Poissonian ground state].
@ Related topics: Landsberg et al AJP(94), Pantellini AJP(00) [in constant g field]; > s.a. Boltzmann Equation; Maxwell-Boltzmann.

Self-Gravitating Gas
@ Statistical mechanics: de Vega et al CSF(99)ap/98; de Vega & Sánchez PLB(00), NPB(02)ap/01, NPB(02)ap/01; de Vega & Siebert PRE(02)ap/01; de Vega & Sánchez ap/05-in, ap/06-in.
@ Related topics: de Vega & Sánchez NPB(05)ap/03 [cluster expansion]; de Vega & Siebert NPB(05) [with dark energy]; Siebert PhD(05)ap; > s.a. gravitating matter.

Other Types > s.a. Chaplygin Gas; composite quantum systems; diffusion; Virial Expansion; Viscosity.
@ Photons: Leff AJP(02) [in intro physics]; > s.a. Adiabatic Transformation; modified lorentz group.
@ Bosons: Lenard JMP(66) [1D, impenetrable]; Chuu et al PRL(05) [sub-Poissonian number fluctuation]; Toms JPA(06) [sm, confined geometry]; Deuar & Drummond JPA(06) [interacting]; Martin IJTP(05) [repulsive potential, polymer representation]; Nattermann AJP(07) [weakly interacting, from heuristics and thermodynamics]; Erdos et al a0806 [ground state energy]; > s.a. Bose-Einstein Condensation.
@ Fermions: Elze et al JPG(80) [ideal, relativistic]; Jin pw(02)apr [of atoms]; Thomas & Gehm AS(04)#3 [cold, optically trapped]; Seiringer CMP(06)mp/04 [pressure]; Lieb et al mp/05-in [dilute, ground state energy]; Chang & Pandharipande PRL(05) [strongly interacting, ground state]; Leboeuf & Roccia PRL(06) [2-component, level density]; Kowalski et al a0712-PRD [relativistic, T = 0].
@ Related topics: Brilliantov & Pöschel 04 [granular; r JPA(05)#47]; > s.a. extended thermodynamics [dense gases].

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