626 research outputs found
Alternative Dispute Resolution in India - ADR: status/effectiveness study
This study focuses on the effectiveness of Alternative Dispute Resolution mechanisms in India. The broad targets included (a) a comparative analysis of institutional ADRs and ad-hoc ADR, (b) cost and time benefit analysis of ADRs in comparison with adjudication through courts; (c) study of the effectiveness of pre-trial mediation centres; and (e) to make concrete suggestions. The study proves that ADR in India has not been that effective when compared to adjudication through courts. The report favored institutional ADRs given the high rate of corruption and bureaucratic hitches prevalent in ad-hoc ADRs. The study also found that pre-trial mediation centres were developing in the right track
Non-perturbative Quantum Dynamics of the Order Parameter in the Pairing Model
We consider quantum dynamics of the order parameter in the discrete pairing
model (Richardson model) in thermodynamic equilibrium. The integrable
Richardson Hamiltonian is represented as a direct sum of Hamiltonians acting in
different Hilbert spaces of single-particle and paired/empty states. This
allows us to factorize the full thermodynamic partition function into a
combination of simple terms associated with real spins on singly-occupied
states and the partition function of the quantum XY-model for Anderson
pseudospins associated with the paired/empty states. Using coherent-state
path-integral, we calculate the effects of superconducting phase fluctuations
exactly. The contribution of superconducting amplitude fluctuations to the
partition function in the broken-symmetry phase is shown to follow from the
Bogoliubov-de Gennes equations in imaginary time. These equations in turn allow
several interesting mappings, e.g., they are shown to be in a one-to-one
correspondence with the one-dimensional Schr\"odinger equation in
supersymmetric Quantum Mechanics. However, the most practically useful approach
to calculate functional determinants is found to be via an analytical
continuation of the quantum order parameter to real time, \Delta(\tau -> it),
such that the problem maps onto that of a driven two-level system. The
contribution of a particular dynamic order parameter to the partition function
is shown to correspond to the sum of the Berry phase and dynamic phase
accumulated by the pseudospin. We also examine a family of exact solutions for
two-level-system dynamics on a class of elliptic functions and suggest a
compact expression to estimate the functional determinants on such
trajectories. The possibility of having quantum soliton solutions co-existing
with classical BCS mean-field is discussed.Comment: 34 pages (v2: Typos corrected, references added
Two-Hole Bound States from a Systematic Low-Energy Effective Field Theory for Magnons and Holes in an Antiferromagnet
Identifying the correct low-energy effective theory for magnons and holes in
an antiferromagnet has remained an open problem for a long time. In analogy to
the effective theory for pions and nucleons in QCD, based on a symmetry
analysis of Hubbard and t-J-type models, we construct a systematic low-energy
effective field theory for magnons and holes located inside pockets centered at
lattice momenta (\pm pi/2a,\pm pi/2a). The effective theory is based on a
nonlinear realization of the spontaneously broken spin symmetry and makes
model-independent universal predictions for the entire class of lightly doped
antiferromagnetic precursors of high-temperature superconductors. The
predictions of the effective theory are exact, order by order in a systematic
low-energy expansion. We derive the one-magnon exchange potentials between two
holes in an otherwise undoped system. Remarkably, in some cases the
corresponding two-hole Schr\"odinger equations can even be solved analytically.
The resulting bound states have d-wave characteristics. The ground state wave
function of two holes residing in different hole pockets has a d_{x^2-y^2}-like
symmetry, while for two holes in the same pocket the symmetry resembles d_{xy}.Comment: 35 pages, 11 figure
Failure of Mean Field Theory at Large N
We study strongly coupled lattice QCD with colors of staggered fermions
in 3+1 dimensions. While mean field theory describes the low temperature
behavior of this theory at large , it fails in the scaling region close to
the finite temperature second order chiral phase transition. The universal
critical region close to the phase transition belongs to the 3d XY universality
class even when becomes large. This is in contrast to Gross-Neveu models
where the critical region shrinks as (the number of flavors) increases and
mean field theory is expected to describe the phase transition exactly in the
limit of infinite . Our work demonstrates that close to second order phase
transitions infrared fluctuations can sometimes be important even when is
strictly infinite.Comment: 4 pages, 3 figure
Vortex distribution in the Lowest Landau Level
We study the vortex distribution of the wave functions minimizing the Gross
Pitaevskii energy for a fast rotating condensate in the Lowest Landau Level
(LLL): we prove that the minimizer cannot have a finite number of zeroes thus
the lattice is infinite, but not uniform. This uses the explicit expression of
the projector onto the LLL. We also show that any slow varying envelope
function can be approximated in the LLL by distorting the lattice. This is used
in particular to approximate the inverted parabola and understand the role of
``invisible'' vortices: the distortion of the lattice is very small in the
Thomas Fermi region but quite large outside, where the "invisible" vortices
lie.Comment: 4 pages, 1 figur
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