We propose a new stage of confiment-decofinment transition, which can be
observed in laboratory. In two-gap superconductors (SCs), two kinds of vortex
exist and each of them carries a continuously variable fraction of the unit
flux quanta Phi_0=h c / 2 e. The confined state of these two is a usual vortex
and stable in the low temperature region of the system under a certain magnetic
field above H_c1. We see an analogy to quarks in a charged pion. An entropy
gain causes two fractional vortices to be deconfined above a certain
temperature.Comment: 5 pages, 3 figures, to be published in Europhys. Let
