11,246 research outputs found
Using torsion to manipulate spin currents
We address the problem of quantum particles moving on a manifold
characterised by the presence of torsion along a preferential axis. In fact,
such a torsion may be taylored by the presence of a single screw dislocation,
whose Burgers vector measures the torsion amplitude. The problem, first treated
in the relativistic limit describing fermions that couple minimally to torsion,
is then analysed in the Pauli limit We show that torsion induces a geometric
potential and also that it couples generically to the phase of the wave
function, giving rise to the possibility of using torsion to manipulate spin
currents in the case of spinor wave functions. These results emerge as an
alternative strategy for using screw dislocations in the design of
spintronic-based devices
Algebraic methods in the theory of generalized Harish-Chandra modules
This paper is a review of results on generalized Harish-Chandra modules in
the framework of cohomological induction. The main results, obtained during the
last 10 years, concern the structure of the fundamental series of
modules, where is a semisimple Lie
algebra and is an arbitrary algebraic reductive in
subalgebra. These results lead to a classification of simple
modules of finite type with generic minimal
types, which we state. We establish a new result about the
Fernando-Kac subalgebra of a fundamental series module. In addition, we pay
special attention to the case when is an eligible subalgebra
(see the definition in section 4) in which we prove stronger versions of our
main results. If is eligible, the fundamental series of
modules yields a natural algebraic generalization
of Harish-Chandra's discrete series modules.Comment: Keywords : generalized Harish-Chandra module, (g,k)-module of finite
type, minimal k-type, Fernando-Kac subalgebra, eligible subalgebra; Pages no.
: 13; Bibliography : 21 item
Credit Enhancement through Financial Engineering: Freeport-McMoRan's Gold-Denominated Depository Shares
In 1993 and early 1994, Freeport McMoRan Copper and Gold (FCX), a mining company, issued two series of gold-denominated depositary shares to raise 430 million dollars expanding their mining capacity in Indonesia. We price the depositary shares using a term structure model for the forward rates implied by gold futures and we show that FCX successfully enhanced the credit quality of the issue. This credit enhancement is achieved because the effect of linking the payoff of the depositary shares to gold reduces default risk and is similar to conventional risk management. However, the bundling of financing and risk management allows the firm to target hedging benefits only to the newly issued securities. The design of the security also overcomes the asset substitution problem. The depositary shares issued by FCX illustrate how firms can enhance credit quality through financial engineering without changing the existing priority ordering of their capital structure.Risk management, Gold-linked, Hybrid Securities
Effective photon mass and exact translating quantum relativistic structures
Using a variation of the celebrated Volkov solution, the Klein-Gordon
equation for a charged particle is reduced to a set of ordinary differential
equations, exactly solvable in specific cases. The new quantum relativistic
structures can reveal a localization in the radial direction perpendicular to
the wave packet propagation, thanks to a non-vanishing scalar potential. The
external electromagnetic field, the particle current density and the charge
density are determined. The stability analysis of the solutions is performed by
means of numerical simulations. The results are useful for the description of a
charged quantum test particle in the relativistic regime, provided spin effects
are not decisive
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