Fractional charges at finite temperature and chemical potential

The behaviour of the fermion charge Q localized on soliton at finite temperature T and chemical potential α is investigated in the one-dimensional continuum model of the linear diatomic polymer. It is shown that the depletion of the fermion charge takes place when T and α tend to its critical values. In the case of the spinless trans-polyacetylene model and N = 1 Gross-Neveu model the discontinuity of the value of Q at α_c is obtained whereas in the model φ⁴ with fermions the continuous transition to zero value of Q(α) occurs.