Daboul, J.2014-05-202014-05-201992-02-21Europhysics Letters. Les Ulis Cedex: Editions Physique, v. 18, n. 3, p. 189-194, 1992.0295-5075http://hdl.handle.net/11449/36607A paradox is pointed out and resolved by proving that the average energy E = [H] of a macroscopic system in thermal equilibrium must increase by the measurement of an observable A which does not commute with the Hamiltonian H. The proof follows as a corollary of a more general result, which states that under certain conditions the expectation value [C] of an observable C should increase by the measurement of another observable A, if [A, C] not-equal 0.189-194engArtigo10.1209/0295-5075/18/3/001WOS:A1992HH05800001Acesso restrito