Abstract
It is shown that new parametersX can be defined such that the heat capacity Cx≡T(∂S/∂T)x is negative, even when the canonical ensemble [i.e., at fixed T=(∂U/∂S)Y and Y≠X] is stable. This implies an extension of the classical theory of polytropes from ideal gases to general fluids. As examples of negative heat capacity systems we treat blackbody radiation and general gas systems with nonsingular κT. For the case of a simple ideal gas we even exhibit an apparatus which enforces a constraint X(p, V)=const that makes Cx<0. We then show that it is possible to infer the statistical mechanics of canonicallyunstable systems-for which even the traditional heat capacities are negative-by imposing constraints that stabilize the associated noncanonical ensembles. Two explicit models are discussed.
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References
P. C. W. Davies,Rep. Prog. Phys. 41:1314 (1978); R. M. Wald,General Relativity (Chicago University Press, Chicago, 1984); D. Pavón and P. T. Landsberg,Gen. Rel. Grav. 20:457 (1988).
D. Lynden-Bell and R. M. Lynden-Bell,Mon. Not. Astron. Soc. 181:405 (1977); P. Hertel and W. Thirring,Ann. Phys. (N.Y.)63:520 (1971).
R. A. Smith and T. M. O'Neil,Phys. Fluids B 2:2961 (1990).
P. T. Landsberg,J. Slat. Phys. 35:159 (1984); D. C. Wright,Phys. Rev. D 21:884 (1980).
F. Schlögl, Z.Phys. 267:77 (1974).
P. T. Landsberg,Thermodynamics and Quantum Statistical Illustrations (Interscience, New York, 1961).
V. J. Menon and D. C. Agrawal,Phys. Lett. 139A:130 (1989).
R. Emden,Gaskugeln (Teubner, Leipzig, 1907).
R. Emden,Encycl. d. Math. Wiss., Vol. VI, 2.B (Teubner, Leipzig, 1922–1934), pp. 373–532; S. Chandrasekhar,An Introduction to the Study of Stellar Structure (Chicago University Press, Chicago, 1939).
H. B. Callen,Thermodynamics and An Introduction to Thermostatistics, 2nd ed. (Wiley, New York, 1987).
P. M. Morse and H. Feshbach,Methods of Theoretical Physics I (McGraw-Hill, New York, 1953), pp. 434–443.
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Landsberg, P.T., Woodard, R.P. Classical fluids of negative heat capacity. J Stat Phys 73, 361–378 (1993). https://doi.org/10.1007/BF01052765
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DOI: https://doi.org/10.1007/BF01052765