Bilayer graphene is a recently isolated and intriguing class of many-body
systems with massive chiral quasiparticles. We present theoretical results for
the electronic compressibility of bilayer graphene that are based on a
four-band continuum band structure model combined with a random phase
approximation treatment of electronic correlations. We find that the
compressibility is strongly suppressed by electron-electron interactions at low
carrier densities. Correlations do not lead to any qualitative new features,
but are crucially important for a quantitative understanding of this
fundamental thermodynamic property of graphene bilayers.Comment: 9 pages, 5 figure