4,369 research outputs found
CP_N Solitons in Quantum Hall Systems
We will present here an elementary pedagogical introduction to
solitons in quantum Hall systems. We begin with a brief introduction to both
models and to quantum Hall (QH) physics. Then we focus on spin and
layer-spin degrees of freedom in QH systems and point out that these are in
fact fields for N=1 and N=3. Excitations in these degrees of freedom
will be shown to be topologically non-trivial soliton solutions of the
corresponding field equations. This is followed by a brief summary of
our own recent work in this area, done with Sankalpa Ghosh. [ Invited Plenary
Lecture at the International Conference on Geometry, Integrability and
Nonlinearity in Condensed Matter & Soft Condensed Matter Physics held at
Bansko, Bulgaria, July 15-20, 2001. ]Comment: Standard revtex format, 18 pages, no figure
Bimerons in Double Layer Quantum Hall Systems
In this paper we discuss bimeron pseudo spin textures for double layer
quantum hall systems with filling factor . Bimerons are excitations
corresponding to bound pairs of merons and anti-merons.
Bimeron solutions have already been studied at great length by other groups
by minimising the microsopic Hamiltonian between microscopic trial
wavefunctions. Here we calculate them by numerically solving coupled nonlinear
partial differential equations arising from extremisation of the effective
action for pseudospin textures. We also calculate the different contributions
to the energy of our bimerons, coming from pseudospin stiffness, capacitance
and coulomb interactions between the merons. Apart from augmenting earlier
results, this allows us to check how good an approximation it is to think of
the bimeron as a pair of rigid objects (merons) with logarithmically growing
energy, and with electric charge . Our differential equation
approach also allows us to study the dependence of the spin texture as a
function of the distance between merons, and the inter layer distance. Lastly,
the technical problem of solving coupled nonlinear partial differential
equations, subject to the special boundary conditions of bimerons is
interesting in its own right.Comment: 8 ps figures included; to be published in IJMP
Solitons in systems of coupled scalar fields
We present a method to obtain soliton solutions to relativistic system of
coupled scalar fields. This is done by examining the energy associated to
static field configurations. In this case we derive a set of first-order
differential equations that solve the equations of motion when the energy
saturates its lower bound. To illustrate the general results, we investigate
some systems described by polynomial interactions in the coupled fields.Comment: RevTex4, 5 page
Revenue incentives at the third tier.
Given the poor level of exploitation in most states of even such sources of revenue as have been legislatively assigned to the fiscal domain of panchayati raj institutions, the most important issue is that of incentives for own revenue collection. Incentives can be built into the design of State-local transfers by deducting local revenue potential from closed-ended grant entitlements, thus deeming local collections as having been realised (upto some stipulated fraction of potential if need be). Such a system can work only if the assessment of revenue potential across panchayat jurisdictions is perceived as cross-sectionally fair, and if it carries minimal costs of assessment for the State government. The jurisdiction-specific indicator must also not carry policy endogeneity, with adverse incentives for provision of public services by PRIs. The paper examines these issues and suggests a way by which the revenue potential can be quantified in an operationally useful way, without adverse incentives. The paper also examines whether State governments should be incentivised by the Centre to implement decentralisation and encourage own revenue generation by PRIs.Revenue potential ; Panchayati raj institutions
Noncommutative Gauge Theory, Divergences and Closed Strings
We study the renormalization of non-commutative gauge theories with matter.
As in the scalar field theory cases, there are logarithmic infrared
divergences resulting from integrating out high momentum modes. In order to
reproduce the correct infrared behaviour, the Wilsonian effective action has to
include certain ''closed string`` modes with prescribed couplings.
In the case of quiver gauge theories, realized in string theory on orbifolds,
we identify the required modes with a set of twisted sector fields. These
closed string modes have exactly the prescribed couplings to correct the
Wilsonian effective action. This provides a concrete origin for the appearance
of closed string modes in noncommutative field theories.Comment: 20 pages, 2 figures, LATE
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