  We start with the chiral density wave(CDW)mean field Hamiltonian in the
momentum space for the pseudo-gapped state of YBCO in the absence of magnetic
field, including the momentum conserving inter-layer tunneling matrix elements
in the Hamiltonian for the tetragonal case, with the principal component of the
order parameter corresponding to idx2-y2 and the secondary one to the dxy. With
the eigenvalues and the eigenvectors of the Hamiltonian matrix we write down
expression for Berry curvature(BC). Only two BC peaks of same magnitude and
opposite signs are obtained at the nodal points of the reconstructed Fermi
surface (RFS) for the pure idx2-y2-density wave case. We establish a relation
between thermodynamic potential of the system and certain spectral functions
for the CDW state. This yields an expression for entropy in closed form. We
show that the transition to the CDW state is a first order one and the entropy
per unit cell increases in this state. We also investigate anomalous Nernst
effect theoretically.
