2,429 research outputs found
Growth and Persistence of Large Business Groups in India
The international business literature is belatedly recognizing the significance of large family-controlled business groups in emerging markets. Most research has focused on analyzing the impact of concentrations of private wealth on economic development in home countries using panel data. This paper examines the growth and persistence of business groups since 1951 in one country – India. Since Independence, the government has attempted to operate an economic policy framework that had, amongst its prime objectives, the curbing of the tendency of business groups to concentrate economic power. As their growth was seen as synonymous with concentration of wealth, business groups became obvious candidates for regulation. Various policy instruments were introduced, such as the Industries (Development and Regulation) (IDR) Act 1951 and the Monopolies and Restrictive Trade Practices (MRTP) Act 1969, with the aim of erecting barriers to their growth. In 1991, economic reform ushered in the removal of the legislative barriers to business group growth. The analysis in this paper concludes that large business groups expanded their share of wealth between 1951 and 1969, but this growth was arrested between 1970 and 1990, and since 1991, it has dwindled. The pre-eminent position of Tata and Birla, as the two largest business groups, remained unchallenged from 1951 until the emergence of the Reliance Group in the late 1990s. However, there has been frequent change in the relative positions of other groups in and out of the Top-20. After economic liberalisation accelerated from 1991, there was significant change in the ranks of business groups in the Top-20. Existing smaller groups or newly emerging groups, particularly in the IT and telecommunications sectors, have replaced many of the previously dominant older groups. This is interpreted as indicating the central role of entrepreneurship in combination with technological innovation, and the opening up of the Indian economy to international competition, in disturbing established business hierarchies in India. More generally, policy intervention appears to have been less effective in breaking up concentrations of economic power in India than economic liberalization and increased competition
Charge-Symmetry-Breaking Three-Nucleon Forces
Leading-order three-nucleon forces that violate isospin symmetry are
calculated in Chiral Perturbation Theory. The effect of the
charge-symmetry-breaking three-nucleon force is investigated in the trinucleon
systems using Faddeev calculations. We find that the contribution of this force
to the 3He - 3H binding-energy difference is approximately 5 keV.Comment: 14 pages, 3 figure
Gravity Duals of Lifshitz-like Fixed Points
We find candidate macroscopic gravity duals for scale-invariant but
non-Lorentz invariant fixed points, which do not have particle number as a
conserved quantity. We compute two-point correlation functions which exhibit
novel behavior relative to their AdS counterparts, and find holographic
renormalization group flows to conformal field theories. Our theories are
characterized by a dynamical critical exponent , which governs the
anisotropy between spatial and temporal scaling , ; we focus on the case with . Such theories describe
multicritical points in certain magnetic materials and liquid crystals, and
have been shown to arise at quantum critical points in toy models of the
cuprate superconductors. This work can be considered a small step towards
making useful dual descriptions of such critical points.Comment: 17 pages, harvmac; v2 comments about behavior of metric near r=0
added (thanks to S. Hartnoll and G. Horowitz
Isospin Breaking in the Pion-Nucleon Coupling from QCD Sum Rules
We use QCD sum rules for the three point function of a pseudoscalar and two
nucleonic currents in order to estimate the charge dependence of the pion
nucleon coupling constant coming from isospin violation in the
strong interaction. The effect can be attributed primarily to the difference of
the quark condensates . For the splitting
we obtain an interval of to , the uncertainties coming mainly from the input
parameters. The charged pion nucleon coupling is found to be the average of
and . Electromagnetic effects are not included.Comment: 18 pages (REVTeX) + 2 figures (as PostScript), to be published in
PRC, replaced with final version: inclusion of pi-eta mixing and N -> N*
transition
Relativistic Lee Model on Riemannian Manifolds
We study the relativistic Lee model on static Riemannian manifolds. The model
is constructed nonperturbatively through its resolvent, which is based on the
so-called principal operator and the heat kernel techniques. It is shown that
making the principal operator well-defined dictates how to renormalize the
parameters of the model. The renormalization of the parameters are the same in
the light front coordinates as in the instant form. Moreover, the
renormalization of the model on Riemannian manifolds agrees with the flat case.
The asymptotic behavior of the renormalized principal operator in the large
number of bosons limit implies that the ground state energy is positive. In 2+1
dimensions, the model requires only a mass renormalization. We obtain rigorous
bounds on the ground state energy for the n-particle sector of 2+1 dimensional
model.Comment: 23 pages, added a new section, corrected typos and slightly different
titl
Coulomb and Liquid Dimer Models in Three Dimensions
We study classical hard-core dimer models on three-dimensional lattices using
analytical approaches and Monte Carlo simulations. On the bipartite cubic
lattice, a local gauge field generalization of the height representation used
on the square lattice predicts that the dimers are in a critical Coulomb phase
with algebraic, dipolar, correlations, in excellent agreement with our
large-scale Monte Carlo simulations. The non-bipartite FCC and Fisher lattices
lack such a representation, and we find that these models have both confined
and exponentially deconfined but no critical phases. We conjecture that
extended critical phases are realized only on bipartite lattices, even in
higher dimensions.Comment: 4 pages with corrections and update
Frustrated minority spins in GeNi2O4
Recently, two consecutive phase transitions were observed, upon cooling, in
an antiferromagnetic spinel GeNiO at K and
K, respectively \cite{matsuno, crawford}. Using unpolarized and polarized
elastic neutron scattering we show that the two transitions are due to the
existence of frustrated minority spins in this compound. Upon cooling, at
the spins on the \kagome planes order ferromagnetically in the
plane and antiferromagnetically between the planes (phase I), leaving the spins
on the triangular planes that separate the \kagome planes frustrated
and disordered. At the lower , the triangular spins also order in the
plane (phase II). We also present a scenario involving exchange
interactions that qualitatively explains the origin of the two purely magnetic
phase transitions
Operator-Based Truncation Scheme Based on the Many-Body Fermion Density Matrix
In [S. A. Cheong and C. L. Henley, cond-mat/0206196 (2002)], we found that
the many-particle eigenvalues and eigenstates of the many-body density matrix
of a block of sites cut out from an infinite chain of
noninteracting spinless fermions can all be constructed out of the one-particle
eigenvalues and one-particle eigenstates respectively. In this paper we
developed a statistical-mechanical analogy between the density matrix
eigenstates and the many-body states of a system of noninteracting fermions.
Each density matrix eigenstate corresponds to a particular set of occupation of
single-particle pseudo-energy levels, and the density matrix eigenstate with
the largest weight, having the structure of a Fermi sea ground state,
unambiguously defines a pseudo-Fermi level. We then outlined the main ideas
behind an operator-based truncation of the density matrix eigenstates, where
single-particle pseudo-energy levels far away from the pseudo-Fermi level are
removed as degrees of freedom. We report numerical evidence for scaling
behaviours in the single-particle pseudo-energy spectrum for different block
sizes and different filling fractions \nbar. With the aid of these
scaling relations, which tells us that the block size plays the role of an
inverse temperature in the statistical-mechanical description of the density
matrix eigenstates and eigenvalues, we looked into the performance of our
operator-based truncation scheme in minimizing the discarded density matrix
weight and the error in calculating the dispersion relation for elementary
excitations. This performance was compared against that of the traditional
density matrix-based truncation scheme, as well as against a operator-based
plane wave truncation scheme, and found to be very satisfactory.Comment: 22 pages in RevTeX4 format, 22 figures. Uses amsmath, amssymb,
graphicx and mathrsfs package
Charge-Independence Breaking in the Two-Pion-Exchange Nucleon-Nucleon Force
Charge-independence breaking due to the pion-mass difference in the (chiral)
two-pion-exchange nucleon-nucleon force is investigated. A general argument
based on symmetries is presented that relates the charge-symmetric part of that
force to the proton-proton case. The static potential linear in that mass
difference is worked out as an explicit example by means of Feynman diagrams,
and this confirms the general argument.Comment: 10 pages, latex, 1 figure -- epsfig.sty required -- To appear in
Phys. Rev.
- …