Starts 10 Feb 2011 11:30
Ends 10 Feb 2011 20:00
Central European Time
ICTP
Strada Costiera, 11 I - 34151 Trieste (Italy)
We present evidence supporting the weakly paired Moore-Read phase in the half-filled second Landau level, focusing on some of the *qualitative* features of its excitations. Based on numerical studies, we study both skyrmions and neutral excitations. Skyrmions are found to be present at low enough fields, and are promoted by disorder [1]. We show that systems with odd particle number at the flux N_\phi=2N-3 can be interpreted as a neutral fermion mode of one unpaired fermion, which is gapped. The energetics of neutral fermions interacting with pairs of quasiparticles is found to be in agreement with predictions for non-abelian statistics of the Ising type with degenerate fusion channels 1 and \psi [2]. In particular, we discuss signatures of the \nu=5/2 Hall liquid in photoluminescence (PL) experiments [3]: The neutral fermion mode is found to have two distinct minima, resulting in a double-peak structure in the PL spectrum [2]. On the other hand, a valence hole in proximity to the 2DEG induces a disorder potential that locally favours skyrmions. Thus PL signals as a probe for spin polarization in the groundstate should be interpreted conservatively. [1] A. Wójs, G. Möller, S. H. Simon, and N. R. Cooper, Phys. Rev. Lett. 104, 086801 (2010). [2] G. Möller, A. Wójs, N. R. Cooper, arXiv:1009.4956. [3] Stern et al., Phys. Rev. Lett. 105, 096801 (2010).
• M. Poropat