The effect of the electron-electron interaction on the Lifshitz transition density in bilayer graphene

We study the renormalization of the effective mass and trigonal warping of bilayer graphene by the electron-electron interaction. One consequence of such a renormalization in the low-energy bands of a bilayer crystal consists of a small reduction of the critical density of the Lifshitz transition (the crossover between the single-pocket and four-pocket topology of the Fermi surface).