Vector Chiral States in Low-Dimensional Quantum-Spin Systems

Spin-polarized transport in low-dimensional systems

Spin relaxation in low dimensional systems

We review some of the newest findings on the spin dynamics of carriers and excitons in GaAs/GaAlAs quantum wells. In intrinsic wells, where the optical properties are dominated by excitonic effects, we show that exciton-exciton interaction produces a breaking of the spin degeneracy in two-dimensional semiconductors. In doped wells, the two spin components of an optically created two-dimensional...

Interface states of quantum spin systems

We review recent results as well as ongoing work and open problems concerning interface states in quantum spin systems at zero and finite temperature.

Cyclic wavelet systems in prime dimensional linear vector spaces

Finite affine groups are given by groups of translations and di- lations on finite cyclic groups. For cyclic groups of prime order we develop a time-scale (wavelet) analysis and show that for a large class of non-zero window signals/vectors, the generated full cyclic wavelet system constitutes a frame whose canonical dual is a cyclic wavelet frame.

Gapless boundary excitations in the quantum Hall states and in the chiral spin states.

Using the gauge invariances, we show that the (fractional and integral) Quantum Hall (QH) states and the chiral spin states must have gapless boundary excitations. The dynamical properties of those gapless excitations are studied. Under some general assumptions, the gapless excitations are shown to form a representation of the U(1) or SU(2) Kac-Moody algebras and to contribute to a specific hea...