17,422 research outputs found
Resonant Raman scattering of quantum wire in strong magnetic field
The resonant Raman scattering of a quantum wire in a strong magnetic field is
studied, focused on the effect of long range Coulomb interaction and the
spin-charge separation. The energy-momentum dispersions of charge and spin
excitation obtained from Raman cross-section show the characteristc cross-over
behaviour induced by inter-edge Coulomb interaction. The "SPE" peak near
resonance in polarized spectra becomes broad due to the momentum dependence of
charge velocity. The broad peak in the depolarized spectra is shown to
originate from the disparity between charge and spin excitation velocity.Comment: RevTex file, 6 pages, no figure: To appear in Int. Jour. Mod. Phys.
Quasi-local charges and asymptotic symmetry generators
The quasi-local formulation of conserved charges through the off-shell
approach is extended to cover the asymptotic symmetry generators. By
introducing identically conserved currents which are appropriate for asymptotic
Killing vectors, we show that the asymptotic symmetry generators can be
understood as quasi-local charges. We also show that this construction is
completely consistent with the on-shell method.Comment: 19 pages; v2 typos fixe
The structure of gauge-invariant ideals of labelled graph -algebras
In this paper, we consider the gauge-invariant ideal structure of a
-algebra associated to a set-finite,
receiver set-finite and weakly left-resolving labelled space
, where is a labelling map assigning
an alphabet to each edge of the directed graph with no sinks. Under the
assumption that an accommodating set is closed under taking
relative complement, it is obtained that there is a one to one correspondence
between the set of all hereditary saturated subsets of and the
gauge-invariant ideals of . For this, we
introduce a quotient labelled space arising
from an equivalence relation on and show the existence
of the -algebra generated by a
universal representation of . Also the
gauge-invariant uniqueness theorem for is
obtained.
For simple labelled graph -algebras
, where is the
smallest accommodating set containing all the generalized vertices, it is
observed that if for each vertex of , a generalized vertex is
finite for some , then is simple if
and only if is strongly cofinal and
disagreeable. This is done by examining the merged labelled graph
of and the common properties that
and
share
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