Droplet formation in a one-dimensional system of attractive spinless fermions

摘要

We report an evidence for a phase separation in a one-dimensional continuoussystem of spinless fermions with a short-range attractive interaction. It isbased on the numerical study of the momentum-dependent ground state energy.While at small interaction strengths it has a conventional Luttinger-liquidshape of periodic arcs on top of the shallow finite-size-induced parabola, thearcs fade away and finally vanish at some finite critical interaction strength.We interpret this result as a condensation of fermions into a liquidone-dimensional droplet and support this conclusion by further arguments.