  We clarify the difference between entangled and nonentangled two-reservoir
mesoscopic Kondo systems and reveal the reason why theories using the Keldysh
formalism, quantum Monte Carlo calculations, and the renormalization group
approaches cannot explain the line shapes of tunneling conductance of
mesoscopic Kondo systems measured by using a two-terminal setup but explain
those of a three-terminal setup. We emphasize that the previous theories study
a nonentangled system, while real two-reservoir mesoscopic Kondo systems are
entangled systems in which two reservoirs are within the coherent region. We
show that two coherent side peaks appearing in tunneling conductance signify
the entanglement between two reservoirs. These side peaks are essential for
explaining the experimental observations for tunneling conductance.
