  Electrons in clean macroscopic samples of graphene exhibit an astonishing
variety of quantum phases when strong perpendicular magnetic field is applied.
These include integer and fractional quantum Hall states as well as symmetry
broken phases and quantum Hall ferromagnetism. Here we show that mesoscopic
graphene flakes in the regime of strong disorder and magnetic field can exhibit
another remarkable quantum phase described by holographic duality to an
extremal black hole in two dimensional anti-de Sitter space. This phase of
matter can be characterized as a maximally chaotic non-Fermi liquid since it is
described by a complex fermion version of the Sachdev-Ye-Kitaev model known to
possess these remarkable properties.
