  Understanding the interplay between disorder, environment and interactions is
key to elucidating the transport properties of open quantum systems, from
excitons in photosynthetic networks to qubits in ion traps. This interplay is
studied here theoretically in the context of environment-assisted quantum
transport (ENAQT), a unique situation in open system where an
environment-induced dephasing can, counter-intuitively, enhance transport.
First, we show a surprising situation where the particle current grows with
increasing disorder, even without dephasing. Then, we suggest a specific
mechanism for ENAQT (which we dub population uniformization) and demonstrate
that it can explain the persistence of ENAQT deep into the disorder-induced
localization regime. Finally, we show that repulsive interactions are
detrimental to ENAQT, and lead to an environment-hampered quantum transport.
Our predictions can readily be tested within the scope of particle current
experimental capabilities.
