We study the unscreened Coulomb interaction in a one-dimensional electron system at low-energy. We use renormalization group methods and a GW approximation, in order to analyze the model. This yields both a strong wavefunction renormalization and a renormalization of the Fermi velocity. The significance of the effects depends on the filling level of the Fermi system. Despite the long-range character of the interaction, the system still falls into the Luttinger liquid universality class, since the effective couplings remain bounded at arbitrarily low energies.
We study the critical properties of one-dimensional electron systems with the
1/rα-type long-range interaction (
α≥1). Using bosonization methods, we discuss how the 1D system exhibits a crossover from the Tomonaga-Luttinger liquid to the Wigner crystal when
α→1. In particular, a detailed analysis is given to the Fermi-edge singularity phenomena when a {\it mobile} core hole is created suddenly in the valence band. It is found that the effect due to the core-hole motion on the Fermi-edge singularity is gradually suppressed as the system approaches the Wigner crystal, and its critical behavior is dominated by the ordinary impurity forward-scattering inherent in a static hole.
The theoretical model of the short-range interacting Luttinger liquid predicts a power-law scaling of the density of states and the momentum distribution function around the Fermi surface, which can be readily tested through tunneling experiments. However, some physical systems have long-range interaction, most notably the Coulomb interaction, leading to significantly different behaviors from the short-range interacting system. In this paper, we revisit the tunneling theory for the one-dimensional electrons interacting via the long-range Coulomb force. We show that even though in a small dynamic range of temperature and bias voltage, the tunneling conductance may appear to have a power-law decay similar to short-range interacting systems, the effective exponent is scale-dependent and slowly increases with decreasing energy. This factor may lead to the sample-to-sample variation in the measured tunneling exponents. We also discuss the crossover to a free Fermi gas at high energy and the effect of the finite size. Our work demonstrates that experimental tunneling measurements in one-dimensional electron systems should be interpreted with great caution when the system is a Coulomb Luttinger liquid.