  In this paper, we examine the viscoelastic properties of integer quantum Hall
(IQH) states in a tilted magnetic field. In particular, we explore to what
extent the tilted-field system behaves like a two-dimensional electron gas with
anisotropic mass in the presence of strain deformations. We first review the
Kubo formalism for viscosity in an external magnetic field, paying particular
attention to the role of rotational symmetry and contact terms. Next, we
compute the conductivity, stress, and viscosity tensors for IQH states in the
presence of a tilted field and vertical confining potential. By comparing our
results with the recently developed bimetric formalism, we show that, at the
level of the contracted Hall viscosity tensor, the mapping between tilted field
and effective mass anisotropy holds only if we simultaneously modify the
background perpendicular magnetic field; in other words, a simultaneous
measurement of the density, contracted Hall viscosity, and Hall conductivity at
fixed particle number can distinguish between tilted field and effective mass
anisotropy. Additionally, we show that in the presence of a tilted magnetic
field, the stress tensor acquires an unusual anisotropic ground state average,
leading to anomalous elastic response functions. We develop a formalism for
projecting a three-dimensional Hamiltonian with confining potential and
magnetic field to a two-dimensional Hamiltonian in order to further address the
phenomenology of the tilted-field IQH fluid. We find that the projected fluid
couples non-minimally to geometric deformations, indicating the presence of
internal geometric degrees of freedom.
