  Finite temperature instantons between meta-stable vacua of correlated
electronic system are solved analytically for quasi one-dimensional Hubbard
model. The instantons produce dynamic symmetry breaking and connect metallic
state with the dual vacua: superconducting (SC) and spin-density wave (SDW)
states. The instantons spread along the Matsubara's imaginary time and possess
the structure similar to the coordinate-space solitonic lattices previously
discovered in quasi one-dimensional Peierls model. On the microscopic level the
inter-vacua excursion is described by mutual transformations between the
"resonating quartets" of the couples of electron-hole and Cooper pairs.
Spectral properties of the electrons in the "instantonic crystal" reveal
pseudo-gap (PG) behavior, with finite fermionic density of states in the center
of the PG and ``flat-band'' outside of it. Analytically derived inverse
temperature scaling of the pseudo-gap and the densities of the SC and SDW
condensates is discussed in the context of ARPES and STM data in high-Tc
cuprates.
