2002/07/09 by Rangan Lahiri, Lahiri, Rangan, Arvind Arvind +3
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #FOS: Physical sciences #Physics Education (physics.ed-ph) #Quantum Mechanics and Applications #Statistical Mechanics (cond-mat.stat-mech) #Statistical Mechanics and Entropy #cond-mat.stat-mech #physics.ed-ph
paper · pdf · doi:10.48550/arxiv.cond-mat/0207246
7 pages revtex4 3 eps figures included using psfig
openalex publication_date 2002/07/09 · arxiv created 2002/07/10 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present an insightful ``derivation'' of the Langevin equation and the\nfluctuation dissipation theorem in the specific context of a heavier particle\nmoving through an ideal gas of much lighter particles. The Newton's Law of\nmotion (m x=F) for the heavy particle reduces to a Langevin equation\n(valid on a coarser time scale) with the assumption that the lighter gas\nparticles follow a Boltzmann velocity distribution. Starting from the\nkinematics of the random collisions we show that (1) the average force <F>\n\∝ - x and (2) the correlation function of the fluctuating force\n\η= F-< F> is related to the strength of the average force.\n