Magnetic-field influence on the collective properties of charge- and spin-density waves

Taking account of a quasi-one-dimensional electron band with an imperfect nesting, we consider the orbital effects of a transverse magnetic field on systems with a charge- or spin-density-wave ground state. Assuming that the cyclotron frequency is small with respect to the critical temperature, we analyze the effects of magnetic field on the quasiparticle Green's function, the equilibrium value of the order parameter, and the density of collective carriers (i.e., the condensate density). It is shown that the order parameter decreases, while the condensate density increases in the magnetic field at low temperatures.