  As hundreds of gas giant planets have been discovered, we study how these
planets form and evolve in different stellar environments, specifically in
multiple stellar systems. In such systems, stellar companions may have a
profound influence on gas giant planet formation and evolution via several
dynamical effects such as truncation and perturbation. We select 84 Kepler
Objects of Interest (KOIs) with gas giant planet candidates. We obtain
high-angular resolution images using telescopes with adaptive optics (AO)
systems. Together with the AO data, we use archival radial velocity data and
dynamical analysis to constrain the presence of stellar companions. We detect
59 stellar companions around 40 KOIs for which we develop methods of testing
their physical association. These methods are based on color information and
galactic stellar population statistics. We find evidence of suppressive planet
formation within 20 AU by comparing stellar multiplicity. The stellar
multiplicity rate for planet host stars is 0$^{+5}_{-0}$\% within 20 AU. In
comparison, the stellar multiplicity rate is 18\%$\pm$2\% for the control
sample, i.e., field stars in the solar neighborhood. The stellar multiplicity
rate for planet host stars is 34\%$\pm$8\% for separations between 20 and 200
AU, which is higher than the control sample at 12\%$\pm$2\%. Beyond 200 AU,
stellar multiplicity rates are comparable between planet host stars and the
control sample. We discuss the implications of the results to gas giant planet
formation and evolution.
