title: Interlayer coherence and entanglement in bilayer quantum Hall states at filling factor ν=2/λ.
abstract: We study coherence and entanglement properties of the state space of a composite bi-fermion (two electrons pierced by λ magnetic flux lines) at one Landau site of a bilayer quantum Hall system. In particular, interlayer imbalance and entanglement (and its fluctuations) are analyzed for a set of U(4) coherent (quasiclassical) states generalizing the standard pseudospin U(2) coherent states for the spin-frozen case. The interplay between spin and pseudospin degrees of freedom opens new possibilities with regard to the spin-frozen case. Actually, spin degrees of freedom make interlayer entanglement more effective and robust under perturbations than in the spin-frozen situation, mainly for a large number of flux quanta λ. Interlayer entanglement of an equilibrium thermal state and its dependence with temperature and bias voltage is also studied for a pseudo-Zeeman interaction.
authors.affiliation: Departamento de Matemática Aplicada, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Calixto
authors.forename: E
authors.initials: E
authors.lastname: Pérez-Romero