  We analytically evaluate the Renyi entropies for the two dimensional free
boson CFT. The CFT is considered to be compactified on a circle and at finite
temperature. The Renyi entropies S_n are evaluated for a single interval using
the two point function of bosonic twist fields on a torus. For the case of the
compact boson, the sum over the classical saddle points results in the
Riemann-Siegel theta function associated with the A_{n-1} lattice. We then
study the Renyi entropies in the decompactification regime. We show that in the
limit when the size of the interval becomes the size of the spatial circle, the
entanglement entropy reduces to the thermal entropy of free bosons on a circle.
We then set up a systematic high temperature expansion of the Renyi entropies
and evaluate the finite size corrections for free bosons. Finally we compare
these finite size corrections both for the free boson CFT and the free fermion
CFT with the one-loop corrections obtained from bulk three dimensional
handlebody spacetimes which have higher genus Riemann surfaces as its boundary.
One-loop corrections in these geometries are entirely determined by quantum
numbers of the excitations present in the bulk. This implies that the leading
finite size corrections contributions from one-loop determinants of the
Chern-Simons gauge field and the Dirac field in the dual geometry should
reproduce that of the free boson and the free fermion CFT respectively. By
evaluating these corrections both in the bulk and in the CFT explicitly we show
that this expectation is indeed true.
