12,783 research outputs found
Mott Gap Excitations and Resonant Inelastic X-Ray Scattering in Doped Cuprates
Predictions are made for the momentum- and carrier-dependent degradation of
the Mott gap upon doping in high-Tc cuprates as would be observed in Cu K-edge
resonant inelastic x-ray scattering (RIXS). The two-dimensional Hubbard model
with second- and third-nearest-neighbor hopping terms has been studied by
numerical exact diagonalization. Special emphasis is placed on the
particle-hole asymmetry of the Mott gap excitations. We argue that the Mott gap
excitations observed by RIXS are significantly influenced by the interaction
between charge carriers and antiferromagnetic correlations.Comment: 4 pages, 4 figures, revised version; to be published in Phys. Rev.
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Theory of RIXS in strongly correlated electron systems: Mott gap excitations in cuprates
We theoretically examine the momentum dependence of resonant inelastic x-ray
scattering (RIXS) spectrum for one-dimensional and two-dimensional cuprates
based on the single-band Hubbard model with realistic parameter values. The
spectrum is calculated by using the numerical diagonalization technique for
finite-size clusters. We focus on excitations across the Mott gap and clarify
spectral features coming from the excitations as well as the physics behind
them. Good agreement between the theoretical and existing experimental results
clearly demonstrates that the RIXS is a potential tool to study the
momentum-dependent charge excitations in strongly correlated electron systems.Comment: 9 pages, 8 figures, Proceedings of 5th International Conference on
Inelastic X-ray Scattering (IXS 2004
On the emergence of gauge structures and generalized spin when quantizing on a coset space
It has been known for some time that there are many inequivalent
quantizations possible when the configuration space of a system is a coset
space G/H. Viewing this classical system as a constrained system on the group
G, we show that these inequivalent quantizations can be recovered from a
generalization of Dirac's approach to the quantization of such a constrained
system within which the classical first class constraints (generating the
H-action on G) are allowed to become anomalous (second class) when quantizing.
The resulting quantum theories are characterized by the emergence of a
Yang-Mills connection, with quantized couplings, and new 'spin' degrees of
{}freedom. Various applications of this procedure are presented in detail:
including a new account of how spin can be described within a path-integral
formalism, and how on S^4 chiral spin degrees of {}freedom emerge, coupled to a
BPST instanton.Comment: 64 pages, plain TeX, DIAS-STP-93-1
On the Lagrangian Realization of the WZNW Reductions
We develop a phase space path-integral approach for deriving the Lagrangian
realization of the models defined by Hamiltonian reduction of the WZNW theory.
We illustrate the uses of the approach by applying it to the models of
non-Abelian chiral bosons, -algebras and the GKO coset construction, and
show that the well-known Sonnenschein's action, the generalized Toda action and
the gauged WZNW model are precisely the Lagrangian realizations of those
models, respectively.Comment: 15 pages, DIAS-STP-92-09/UdeM-LPN-TH-92-9
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