Zero-bias anomaly in one-dimensional tunneling contacts

We study the Coulomb interaction effects on the tunneling conductance of a contact constructed of two parallel quantum wires. The following contacts are considered: two clean identical quantum wires, two disordered identical quantum wires, and asymmetric contact of one clean and another disordered quantum wires. We show that the low-voltage anomaly of the tunneling conductance is less singular than the low-energy anomaly of the one-particle density of states.