We propose a new system where electron and hole states are electrostatically confined into a quantum ring in bilayer graphene. These structures can be created by tuning the gap of the graphene bilayer using nanostructured gates or by position-dependent doping. The energy levels have a magnetic field (B(0)) dependence that is strikingly distinct from that of usual semiconductor quantum rings. In...

G. Rastelli,1,2 I. M. Pop,3,4 and F. W. J. Hekking1 1Université Grenoble 1/CNRS, LPMMC UMR 5493, B.P. 166, 38042 Grenoble, France 2Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany 3Institut Néel, CNRS, and Université Joseph Fourier, B.P. 166, 38042 Grenoble, France 4Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA (Received 6 January 2012; rev...

The ideal I 1 generated by the 2 2 quantum minors in the coordinate algebra of quantum matrices, O q (M m;n (k)), is investigated. Analogues of the First and Second Fundamental Theorems of Invariant Theory are proved. In particular, it is shown that I 1 is a completely prime ideal, that is, O q (M m;n (k))=I 1 is an integral domain, and that O q (M m;n (k))=I 1 is the ring of coinvariants of a ...

We discuss the toplogical sigma model on an orbifold target space. We describe the moduli space of classical minima for computing correlation functions involving twisted operators, and show, through a detailed computation of an orbifold of CP by the dihedral group D4, how to compute the complete ring of observables. Through this procedure, we compute all the rings from dihedral CP orbifolds; we...

We study charge transport driven by deformations in molecular rings and chains. Level crossings and the associated Longuet-Higgins phase play a central role in this theory. In molecular rings a vanishing cycle of shears pinching a gap closure leads, generically, to diverging charge transport around the ring. We call such behavior homeopathic. In an infinite chain such a cycle leads to integral ...

We prove a conjecture made by Brundan and Kleshchev on the nilpotency degree of cyclotomic quotients of rings that categorify one-half of quantum sl(k).

stability of the π-π stacking interactions in the ben||n-substituted-coronene complexes was studied using the computational quantum chemistry methods (where ben is benzene and || denotes π-π stacking interaction, and n-substituted-coronene is coronene molecule which substituted with different number of n atoms). the results reveal simultaneous effects of structure and number of heteroatom on th...

A type II GaSb quantum ring solar cell is fabricated and measured under the concentrated sunlight. The external quantum efficiency confirms the extended absorption from the quantum rings at long wavelength coinciding with the photoluminescence results. The short-circuit current of the quantum ring devices is 5.1% to 9.9% more than the GaAs reference's under various concentrations. While the qua...

After some earlier work on single operators, von Neumann turned to families of operators in [1]. He initiated the study of rings of operators which are commonly called von Neumann algebras today. The papers which constitute the series “Rings of operators” opened a new field in mathematics and influenced research for half a century (or even longer). In the standard theory of modern operator alge...

Given a Hecke symmetry R, one can define a matrix bialgebra ER and a matrix Hopf algebra HR, which are called function rings on the matrix quantum semi-group and matrix quantum groups associated to R. We show that for an even Hecke symmetry, the rational representations of the corresponding quantum group are absolutely reducible and that the fusion coefficients of simple representations depend ...