  In this paper we introduce a new procedure on precise analysis of various
physical manifestations in superconducting Qubits using the concept of Feynman
path integral in quantum mechanics and quantum field theory. Three specific
problem are discussed, we devote the main efforts to studying the wave function
and imaginary part of the energy of the pseudo ground state of the Hamiltonian
in Phase Qubits and we estimate decay rate, and thus the life time of meta
stable states using the approach of 't Hooft's Instantons model. Correction to
the Tilted-Washboard potential and current of Phase Qubits by precise analysis
of Ginzburg-Landau's free energy equation has been considered. Also we evaluate
the most accurate value of energy levels and wave function in Charge and Flux
Qubits by Semi classical approximation in path integral formalism by
considering limits of experimental errors, comparing them with WKB results and
finally, we try to study more specific the evolution of spectrum of Hamiltonian
in time after addition of interaction Hamiltonian, in order to obtain the high
fidelity quantum gates.
