6 research outputs found
Hierarchical structure in the orbital entanglement spectrum in Fractional Quantum Hall systems
We investigate the non-universal part of the orbital entanglement spectrum
(OES) of the nu = 1/3 fractional quantum Hall effect (FQH) ground-state with
Coulomb interactions. The non-universal part of the spectrum is the part that
is missing in the Laughlin model state OES whose level counting is completely
determined by its topological order. We find that the OES levels of the Coulomb
interaction ground-state are organized in a hierarchical structure that mimic
the excitation-energy structure of the model pseudopotential Hamiltonian which
has a Laughlin ground state. These structures can be accurately modeled using
Jain's "composite fermion" quasihole-quasiparticle excitation wavefunctions. To
emphasize the connection between the entanglement spectrum and the energy
spectrum, we also consider the thermodynamical OES of the model pseudopotential
Hamiltonian at finite temperature. The observed good match between the
thermodynamical OES and the Coulomb OES suggests a relation between the
entanglement gap and the true energy gap.Comment: 16 pages, 19 figure
Density Matrix Recursion Method: Genuine Multisite Entanglement Distinguishes Odd from Even Quantum Heisenberg Ladders
We introduce an analytical iterative method, the density matrix recursion
method, to generate arbitrary reduced density matrices of superpositions of
short-range dimer coverings on periodic or non-periodic quantum spin-1/2 ladder
lattices, with an arbitrary number of legs. The method can be used to calculate
bipartite as well as multipartite physical properties, including bipartite and
multi-partite entanglement. We apply this technique to distinguish between
even- and odd-legged ladders. Specifically, we show that while genuine
multi-partite entanglement decreases with increasing system size for the
even-legged ladder states, it does the opposite for odd-legged ones.Comment: 13 pages, 3 figures, iopart.cls, final edited versio