  The field-induced transition in one-dimensional S=1 Heisenberg
antiferromagnet with single-ion anisotropy in the presence of a transverse
magnetic field is obtained on the basis of the Schwinger boson mean-field
theory. The behaviors of the specific heat and susceptibility as functions of
temperature as well as the applied transverse field are explored, which are
found to be different from the results obtained under a longitudinal field. The
anomalies of the specific heat at low temperatures, which might be an
indicative of a field-induced transition from a Luttinger liquid phase to an
ordered phase, are explicitly uncovered under the transverse field. A schematic
phase diagram is proposed. The theoretical results are compared with
experimental observations.
