dc.description.abstract 
<p>This dissertation describes the first experimental measurement of the energy and
interaction dependent shear viscosity $\eta$ and bulk viscosity $\zeta$ in the hydrodynamic
expansion of a twocomponent Fermi gas near a broad collisional (Feshbach) resonance.
This expansion also provides a precise test of scale invariance and an examination
of local thermal equilibrium as a function of interaction strength. After release
from an anisotropic optical trap, we observe that a resonantly interacting gas obeys
scaleinvariant hydrodynamics, where the mean square cloud size $\langle{\mathbf{r}}^2\rangle=\langle
x^2+y^2+z^2\rangle$ expands ballistically (like a noninteracting gas) and the energyaveraged
bulk viscosity is consistent with zero, $0.00(0.04)\,\hbar\,n$, with $n$ the density.
In contrast, the aspect ratios of the cloud exhibit anisotropic ``elliptic" flow with
an energydependent shear viscosity. Tuning away from resonance, we observe conformal
symmetry breaking, where $\langle{\mathbf{r}}^2\rangle$ deviates from ballistic
flow. We find that $\eta$ has both a quadratic and a linear dependence on the interaction
strength $1/({k_{FI}a})$, where $a$ is the swave scattering length and $k_{FI}$ is
the Fermi wave vector for an ideal gas at the trap center. At low energy, the minimum
is less than the resonant value and is significantly shifted toward the BEC side of
resonance, to $1/(k_{FI}a) = 0.2$.</p>

