  Motivated by the recently developed duality between elasticity of a crystal
and a symmetric tensor gauge theory by Pretko and Radzihovsky, we explore its
classical analog, that is a dual theory of the dislocation-mediated melting of
a two-dimensional crystal, formulated in terms of a higher derivative vector
sine-Gordon model. It provides a transparent description of the continuous
two-stage melting in terms of the renormalization-group relevance of two cosine
operators that control the sequential unbinding of dislocations and
disclinations, respectively corresponding to the crystal-to-hexatic and
hexatic-to-isotropic fluid transitions. This renormalization-group analysis
compactly reproduces seminal results of the Coulomb gas description, such as
the flows of the elastic couplings and of the dislocation and disclination
fugacities, as well the temperature dependence of the associated correlation
lengths.
