  In quantum optics, it is common to assume that atoms are point-like objects
compared to the wavelength of the electromagnetic field they interact with.
However, this dipole approximation is not always valid, e.g., if atoms couple
to the field at multiple discrete points. Previous work has shown that
superconducting qubits coupled to a one-dimensional waveguide can behave as
such "giant atoms" and then can interact through the waveguide without
decohering, a phenomenon that is not possible with small atoms. Here, we show
that this decoherence-free interaction is also possible when the coupling to
the waveguide is chiral, i.e., when the coupling depends on the propagation
direction of the light. Furthermore, we derive conditions under which the giant
atoms in such chiral architectures exhibit dark states. In particular, we show
that unlike small atoms, giant atoms in a chiral waveguide can reach a dark
state even without being excited by a coherent drive. We also show that in the
driven-dissipative regime, dark states can be populated faster in giant atoms.
The results presented here lay a foundation for applications based on giant
atoms in quantum simulations and quantum networks with chiral settings.
