Some of supersymmetric Chern-Simons theories are known to exhibit
supersymmetry breaking when the Chern-Simons level is less than a certain
number. The mechanism of the supersymmetry breaking is, however, not clear from
the field theory viewpoint. In this paper, we discuss vacuum states of N=2 pure Chern-Simons theory and N=2 Chern-Simons-matter theories of
quiver type using related theories in which Chern-Simons terms are replaced
with (anti-)fundamental chiral multiplets. In the latter theories,
supersymmetry breaking can be shown to occur by examining that the vacuum
energy is non-zero.Comment: 17 pages, 3 figures, v2) references adde