Extended hubbard model with ring exchange: a route to a non-Abelian topological phase

We propose an extended Hubbard model on a 2D kagome lattice with an additional ring exchange term. The particles can be either bosons or spinless fermions. We analyze the model at the special filling fraction 1/6, where it is closely related to the quantum dimer model. We show how to arrive at an exactly soluble point whose ground state is the "d-isotopy" transition point into a stable phase with a certain type of non-Abelian topological order. Near the "special" values, d=2cos(pi/(k+2), this topological phase has anyonic excitations closely related to SU(2) Chern-Simons theory at level k.     

Numerical calculation of the neutral fermion gap at the ν=5/2 fractional quantum Hall state

We present the first numerical computation of the neutral fermion gap, Δ(F), in the ν=5/2 quantum Hall state, which is analogous to the energy gap for a Bogoliubov-de Gennes quasiparticle in a superconductor. We find Δ(F)≈0.027e(2)/ε?(0), comparable to the charge gap. We also deduce an effective Fermi velocity v(F) for neutral fermions from the low-energy spectra for odd numbers of electrons, and thereby obtain a correlation length ξ(F)=v(F)/Δ(F)≈1.3?(0). We comment on implications for experiments, topological quantum information processing, and electronic mechanisms of superconductivity.     

Effects of dissipation on a quantum critical point with disorder

We study the effects of dissipation on a disordered quantum phase transition with O(N) order-parameter symmetry by applying a strong-disorder renormalization group to the Landau-Ginzburg-Wilson field theory of the problem. We find that Ohmic dissipation results in a nonperturbative infinite-randomness critical point with unconventional activated dynamical scaling while super-Ohmic damping leads to conventional behavior. We discuss applications to the superconductor-metal transition in nanowires and to the Hertz theory of the itinerant antiferromagnetic transition.     

Proton-deuteron elastic scattering at 135 MeV with BINA

Differential cross sections and vector analyzing powers for the p + d → p + d reaction have been measured using a new experimental setup (BINA) at KVI. The data are compared with published results and are found to be significantly different.     

Syntheses of ethyl 3-deoxy-3,3-difluoro-d-arabino-heptulosonate and analogues

The difluorinated analogues of 3-deoxy-d-arabino-heptulosonic acid (DAH) 12, 24 and its enantiomer have been synthesised from d- and l-erythrose via a Reformatsky reaction which gave a mixture of diastereoiosmers in favour of the anti isomer.     

β-Cyclodextrin catalyzed access to fused 1,8-dihydroimidazo[2,3-b]indoles via one-pot multicomponent cascade in aqueous ethanol: Supramolecular approach toward sustainability

An eco-friendly multicomponent synthesis of substituted imidazole derivatives catalyzed by β-cyclodextrin (β-CD) was scrutinized for the first time via a one-pot three-compound reaction of aldehyde, isatin, and ammonium acetate in H₂O–EtOH at 80°C. β-CD is a supramolecule, highly efficient, biodegradable, and recyclable catalyst used to produce high yields of desired 1,8-dihydroimidazo[2,3-b]indoles. The developed protocol contains number of advantages like nontoxic, inexpensive catalyst; green reaction condition; easily available starting material; shorter reaction time; and good yields.