  Indications of density-wave states in underdoped cuprates, coming from recent
STM (scanning tunneling microscopy) and Hall-resistance measurements, have
raised new concerns whether stripes could be stabilized in the superconducting
phase of cuprate materials, even in the absence of antiferromagnetism. Here, we
investigate this issue using state-of-the-art quantum Monte Carlo calculations
of a $t-J$ model. In particular we consider the stability of unidirectional
hole domains in a modulated superconducting background, by taking into account
the effect of tetragonal-lattice distortions, next-nearest neighbor hopping and
long-range Coulomb repulsion.
