Quantum field theory in curved graphene spacetimes, Lobachevsky geometry, Weyl symmetry, Hawking effect, and all that

Abstract

The solutions of many issues, of the ongoing efforts to make deformed graphene a tabletop quantum field theory in curved spacetimes, are presented. A detailed explanation of the special features of curved spacetimes, originating from embedding portions of the Lobachevsky plane into ${\mathbf{R}}^{3}$, is given, and the special role of coordinates for the physical realizations in graphene is explicitly shown, in general, and for various examples. The Rindler spacetime is reobtained, with new important differences with respect to earlier results. The de Sitter spacetime naturally emerges, for the first time, paving the way to future applications in cosmology. The role of the Ba\~nados, Teitelboim, and Zanelli (BTZ) black hole is also briefly addressed. The singular boundary of the pseudospheres, ``Hilbert horizon,'' is seen to be closely related to the event horizon of the Rindler, de Sitter, and BTZ kind. This gives new, and stronger, arguments for the Hawking phenomenon to take place. An important geometric parameter, $c$, overlooked in earlier work, takes here its place for physical applications, and it is shown to be related to graphene's lattice spacing, $\ensuremath{\ell}$. It is shown that all surfaces of constant negative curvature, $\mathcal{K}=\ensuremath{-}{r}^{\ensuremath{-}2}$, are unified, in the limit $c/r\ensuremath{\rightarrow}0$, where they are locally applicable to the Beltrami pseudosphere. This, and $c=\ensuremath{\ell}$, allow us (a) to have a phenomenological control on the reaching of the horizon; (b) to use spacetimes different from the Rindler spacetime for the Hawking phenomenon; and (c) to approach the generic surface of the family. An improved expression for the thermal LDOS is obtained. A nonthermal term for the total LDOS is found. It takes into account (i) the peculiarities of the graphene-based Rindler spacetime; (ii) the finiteness of a laboratory surface; and (iii) the optimal use of the Minkowski quantum vacuum, through the choice of this Minkowski-static boundary.