  We analyze the formation of multi-particle bound states in ladders with
frustrated kinetic energy in two component bosonic and two component fermionic
systems. We focus on the regime of light doping relative to insulating states
at half-filling, spin polarization close to 100 percent, and strong repulsive
interactions. A special feature of these systems is that the binding energy
scales with single particle tunneling $t$ rather than exchange interactions,
since effective attraction arises from alleviating kinetic frustration. For two
component Fermi systems on a zigzag ladder we find a bound state between a hole
and a flipped spin (magnon) with a binding energy that can be as large as
$0.6t$. We demonstrate that magnon-hole attraction leads to formation of
clusters comprised of several holes and magnons and expound on
antiferromagentic correlations for the transverse spin components inside the
clusters. We identify several many-body states that result from
self-organization of multi-particle bound states, including a Luttinger liquid
of hole-magnon pairs and a density wave state of two hole - three magnon
composites. We establish a symmetry between the spectra of Bose and Fermi
systems and use it to establish the existence of antibound states in two
component Bose mixtures with SU(2) symmetric repulsion on a zigzag ladder. We
also consider Bose and Fermi systems on a square ladder with flux and
demonstrate that both systems support bound states. We discuss experimental
signatures of multi-particle bound states in both equilibrium and dynamical
experiments. We point out intriguing connections between these systems and the
quark bag model in QCD.
