  Interactions between out-of-plane dipoles in bosonic gases enable the
long-range propagation of excitons. The lack of direct control over collective
dipolar properties has hitherto limited the degrees of tunability and the
microscopic understanding of exciton transport. In this work, we modulate the
layer hybridization and interplay between many-body interactions of excitons in
a van der Waals heterostructure with an applied vertical electric field. By
performing spatiotemporally resolved measurements supported by microscopic
theory, we uncover the dipole-dependent properties and transport of excitons
with different degrees of hybridization. Moreover, we find constant emission
quantum yields of the transporting species as a function of excitation power
with dominating radiative decay mechanisms over nonradiative ones, a
fundamental requirement for efficient excitonic devices. Our findings provide a
complete picture of the many-body effects in the transport of dilute exciton
gases and have crucial implications for the study of emerging states of matter,
such as Bose-Einstein condensation, as well as for optoelectronic applications
based on exciton propagation.
