  The search for dual supermassive black holes (SMBHs) is of immense interest
in modern astrophysics. Galaxy mergers may be an important route to fuel and to
produce SMBH pairs. Actively accreting SMBH pairs can be observed as a dual
quasar, which are vital probes of SMBH growth. Gaia observations have enabled a
novel technique to systematically search for such dual quasars at previously
unreachable sub-kpc scales, based on the small jitters of the light centroid as
the two quasars vary stochastically. Here we present the first detailed study
of a 0.46'', 3.8 kpc separation, VODKA-selected dual quasar, J0749+2255, at
$z=2.17$ using JWST/NIRSpec integral field unit spectroscopy. This is one of
the most distant, small separation dual quasars identified today. Dual quasars
at cosmic noon are not well characterized. We detect the faint ionized gas of
the host galaxy, best traced by the narrow \ha\ emission. Line ratio
diagnostics show a mix of ionization from the two quasars and intense star
formation. The spatially-resolved spectra of the two quasars suggest that they
have very similar black hole properties (two $M_{BH}\sim 10^9\
\textrm{M}_{\odot}$ with large Eddington ratio reaching $L/L_{Edd}\sim0.2$)
hinting at the possible synchronized growth and accretion from the same gas
supply. Surprisingly, the ionized gas kinematics suggest an extended, rotating
disk rather than a disturbed system that would be expected in a major gas-rich
galaxy merger. While it is unclear if J0749+2255 is representative of the dual
quasar evolution, the observations with JWST revealed a major puzzle. It would
be interesting to see what observations of other dual quasars will show.
