Quantizing higher-spin gravity in free-field variables

We study the formulation of massless higher-spin gravity on AdS(3) in a gauge in which the fundamental variables satisfy free field Poisson brackets. This gauge choice leaves a small portion of the gauge freedom un fixed, which should be further quotiented out. We show that doing so leads to a bulk version of the Coulomb gas formalism for W-N CFT's: the generators of the residual gauge symmetries are the classical limits of screening charges, while the gauge-invariant observables are classical WN charges. Quantization in these variables can be carried out using standard techniques and makes manifest a remnant of the triality symmetry of W-infinity [lambda]. This symmetry can be used to argue that the theory should be supplemented with additional matter content which is precisely that of the Prokushkin-Vasiliev theory. As a further application, we use our formulation to quantize a class of conical surplus solutions and confirm the conjecture that these are dual to specific degenerate WN primaries, to all orders in the large central charge expansion.