Brown--Henneaux central charge ($c=3R_{\mathrm{AdS}}/(2G)$)

The Brown--Henneaux central charge is the central charge of the two-dimensional conformal field theory dual to Einstein gravity on ${\mathrm{AdS}}_3$:

For a unit spatial circle, the vacuum energy of a two-dimensional conformal field theory is $E_0=-c/12$. It arises from the anomalous Schwarzian shift when the plane vacuum is mapped to the cylinder and is dual to the renormalized energy of global ${\mathrm{AdS}}_3$.