Optical absorption in the soliton lattice state of a double quantum well system

For sufficiently small separation between layers in a double quantum well system, the ground state of the two-dimensional electron gas at filling factor $\nu =1\mathrm{}$ has an interwell phase coherence even in the absence of tunneling. With tunneling, this coherent state goes through a commensurate-incommensurate transition as the sample is tilted with respect to the quantizing magnetic field at $\nu =1.\mathrm{}$ In this article, we compute the change in the infrared absorption spectrum of the electron gas when the ground state evolves from the commensurate state at small tilt angle to the soliton lattice state at larger tilt angle. We also comment on the possibility of observing experimentally the distinctive signature of the soliton lattice in the absorption spectrum.