  Traditionally the Nernst and Ettingshausen effects in the vortex liquid are
described in terms of the "transport entropy" of vortices, S_d. According to
current theories, the main contribution to S_d is originated from the
electromagnetic free energy, F^{em}, which includes kinetic and magnetic energy
of superconducting currents circulating around vortex cores. However, this
concept contradicts the London postulate, according to which a supercurrent
consists of macroscopic number of particles in a single quantum state and does
not transfer any entropy. Here we resolve this contradiction and show that the
transport entropy is just ordinary thermodynamic entropy transferred by cores.
Only in this form the theory becomes simultaneously consistent with the London
postulate and the Onsager principle. The revised theory explains measured
temperature dependence S_d. The linear increase of S_d at low temperatures is
determined by the entropy of electrons in the core, then S_d reaches a maximum
at roughly T_c/2 and then vanishes due to increase of the background entropy.
