Observation of a linearly dispersing collective mode in a quantum hall ferromagnet.

@article{Spielman2001ObservationOA,
  title={Observation of a linearly dispersing collective mode in a quantum hall ferromagnet.},
  author={I. Spielman and J. Eisenstein and L. Pfeiffer and K. West},
  journal={Physical review letters},
  year={2001},
  volume={87 3},
  pages={
          036803
        }
}
Double-layer two-dimensional electron systems can exhibit a fascinating collective phase believed to display both quantum ferromagnetism and excitonic superfluidity. This unusual phase has recently been found to exhibit tunneling phenomena reminiscent of the Josephson effect. A key element of the theoretical understanding of this bizarre quantum fluid is the existence of linearly dispersing Goldstone collective modes. Using the method of tunneling spectroscopy, we have demonstrated the… Expand