کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1857531 | 1529906 | 2011 | 14 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Microscopic diagonal entropy and its connection to basic thermodynamic relations Microscopic diagonal entropy and its connection to basic thermodynamic relations](/preview/png/1857531.png)
We define a diagonal entropy (d-entropy) for an arbitrary Hamiltonian system as Sd=-∑nρnnlnρnnSd=-∑nρnnlnρnn with the sum taken over the basis of instantaneous energy states. In equilibrium this entropy coincides with the conventional von Neumann entropy Sn = −Trρ ln ρ. However, in contrast to Sn, the d-entropy is not conserved in time in closed Hamiltonian systems. If the system is initially in stationary state then in accord with the second law of thermodynamics the d-entropy can only increase or stay the same. We also show that the d-entropy can be expressed through the energy distribution function and thus it is measurable, at least in principle. Under very generic assumptions of the locality of the Hamiltonian and non-integrability the d-entropy becomes a unique function of the average energy in large systems and automatically satisfies the fundamental thermodynamic relation. This relation reduces to the first law of thermodynamics for quasi-static processes. The d-entropy is also automatically conserved for adiabatic processes. We illustrate our results with explicit examples and show that Sd behaves consistently with expectations from thermodynamics.
Journal: Annals of Physics - Volume 326, Issue 2, February 2011, Pages 486–499