  The intriguing many-body phases of quantum matter arise from the interplay of
particle interactions, spatial symmetries, and external fields. Generating
these phases in an engineered system could provide deeper insight into their
nature and the potential for harnessing their unique properties. However,
concurrently bringing together the main ingredients for realizing many-body
phenomena in a single experimental platform is a major challenge. Using
superconducting qubits, we simultaneously realize synthetic magnetic fields and
strong particle interactions, which are among the essential elements for
studying quantum magnetism and fractional quantum Hall (FQH) phenomena. The
artificial magnetic fields are synthesized by sinusoidally modulating the qubit
couplings. In a closed loop formed by the three qubits, we observe the
directional circulation of photons, a signature of broken time-reversal
symmetry. We demonstrate strong interactions via the creation of
photon-vacancies, or "holes", which circulate in the opposite direction. The
combination of these key elements results in chiral groundstate currents, the
first direct measurement of persistent currents in low-lying eigenstates of
strongly interacting bosons. The observation of chiral currents at such a small
scale is interesting and suggests that the rich many-body physics could survive
to smaller scales. We also motivate the feasibility of creating FQH states with
near future superconducting technologies. Our work introduces an experimental
platform for engineering quantum phases of strongly interacting photons and
highlight a path toward realization of bosonic FQH states.
