Infinite density matrix renormalization group for multicomponent quantum Hall systems

While the simplest quantum Hall plateaus, such as the ν=1/3 state in GaAs, can be conveniently analyzed by assuming only a single active Landau level participates, for many phases the spin, valley, bilayer, subband, or higher-Landau-level indices play an important role. These “multicomponent” problems are difficult to study using exact diagonalization because each component increases the difficulty exponentially. An important example is the plateau at ν=5/2, where scattering into higher Landau levels chooses between the competing non-Abelian Pfaffian and anti-Pfaffian states. We address the methodological issues required to apply the infinite density matrix renormalization group to quantum Hall systems with multiple components and long-range Coulomb interactions, greatly extending accessible system sizes. As an initial application we study the problem of Landau-level mixing in the ν=5/2 state. Within the approach to Landau-level mixing used here, we find that at the Coulomb point the anti-Pfaffian state is preferred over the Pfaffian state over a range of Landau-level mixing up to the experimentally relevant values.     «

While the simplest quantum Hall plateaus, such as the ν=1/3 state in GaAs, can be conveniently analyzed by assuming only a single active Landau level participates, for many phases the spin, valley, bilayer, subband, or higher-Landau-level indices play an important role. These “multicomponent” problems are difficult to study using exact diagonalization because each component increases the difficulty exponentially. An important example is the plateau at ν=5/2, where scattering into higher Landau l...     »