Quantum Lifshitz point in the infinite dimensional Hubbard model

TL;DR

This paper demonstrates that the Gutzwiller wave function effectively predicts magnetic phase boundaries in the infinite dimensional Hubbard model, revealing a quantum Lifshitz point where different magnetic phases meet.

Contribution

It extends phase diagrams of the infinite dimensional Hubbard model using Gutzwiller wave functions and identifies a new quantum Lifshitz point in the hypercubic lattice.

Findings

Gutzwiller wave function accurately predicts phase boundaries.

Presence of an incommensurate phase between ferromagnetic and paramagnetic phases.

Identification of a quantum Lifshitz point where phases and order parameters meet.

Abstract

We show that the Gutzwiller variational wave function is surprisingly accurate for the computation of magnetic phase boundaries in the infinite dimensional Hubbard model. This allows us to substantially extend known phase diagrams. For both the half-hypercubic and the hypercubic lattice a large part of the phase diagram is occupied by an incommensurate phase, intermediate between the ferromagnetic and the paramagnetic phase. In case of the hypercubic lattice the three phases join at a new quantum Lifshitz point at which the order parameter is critical and the stiffness vanishes.