INTRASUBBAND EXCITATIONS OF COMPOSITE FERMIONS IN A QUANTUM-WIRE

We investigate the intrasubband excitation spectra of a composite ferm ion system in a quantum wire at the filling factor 1/3. Using a second -quantized fermion path-integral approach, we derive the density-densi ty correlation function in the system. We find that at long-wavelength limit the excitation energy of the collective mode has a gap, and tha t in long-wavelength single-particle excitations are suppressed. We al so show that at the finite wave vector the collective mode dispersion has a magnetoroton dip. With increasing the strength of the confining potential, this dip vanishes.