761,583 research outputs found
Political Yardstick Competition, Economic Integration, and Constitutional Choice in a Federation
This paper investigates the behavior of rent-seeking politicians in an environment of increasing economic integration. The focus of the paper is on the implications of globalization-induced political yardstick competition for constitutional design with a view to the current discussion in the European Union. In contrast to the established literature, we carefully portray the double-tiered government structure in federal systems. The number of lower-tier governments and the allocation of policy responsibilities to the two levels of government are subject to constitutional choice.Economic Integration, Federalism, Political Economy, Yardstick Competition
Colluding through Suppliers
In a dynamic game between N retailers and a large number of suppliers, I show that inefficient contracting emerges as a mechanism to implement collusion among retailers, building on the natural ‘complementarity’ between retail and wholesale prices. When efficient collusion is not sustainable, this complementarity allows retailers to rely on inefficient input supply, entailing double marginalization and negative franchise fees, to squeeze the wedge between collusive and deviation profits. I also study the role of communication on the equilibrium outcomes of games where retailers have the initiative. It turns out that communication is indeed fundamental to strengthen cartels' sustainability, although generating efficiency losses.Bertrand competition, double marginalization, collusion, competing hierarchies.
Forecasting the CATS benchmark with the Double Vector Quantization method
The Double Vector Quantization method, a long-term forecasting method based
on the SOM algorithm, has been used to predict the 100 missing values of the
CATS competition data set. An analysis of the proposed time series is provided
to estimate the dimension of the auto-regressive part of this nonlinear
auto-regressive forecasting method. Based on this analysis experimental results
using the Double Vector Quantization (DVQ) method are presented and discussed.
As one of the features of the DVQ method is its ability to predict scalars as
well as vectors of values, the number of iterative predictions needed to reach
the prediction horizon is further observed. The method stability for the long
term allows obtaining reliable values for a rather long-term forecasting
horizon.Comment: Accepted for publication in Neurocomputing, Elsevie
Ashkin-Teller universality in a quantum double model of Ising anyons
We study a quantum double model whose degrees of freedom are Ising anyons.
The terms of the Hamiltonian of this system give rise to a competition between
single and double topologies. By studying the energy spectra of the Hamiltonian
at different values of the coupling constants, we find extended gapless regions
which include a large number of critical points described by conformal field
theories with central charge c=1. These theories are part of the Z_2 orbifold
of the bosonic theory compactified on a circle. We observe that the Hilbert
space of our anyonic model can be associated with extended Dynkin diagrams of
affine Lie algebras which yields exact solutions at some critical points. In
certain special regimes, our model corresponds to the Hamiltonian limit of the
Ashkin-Teller model, and hence integrability over a wide range of coupling
parameters is established.Comment: 11 pages, minor revision
Price Discrimination Through Barter: A Theory and Evidence from Russia
We build a model of imperfect competition where firms can sell for cash or in-kind payments. Barter is indivisible, and there is no double coincidence of wants. Despite these deficiencies, barter emerges in equilibrium as a means of price discrimination if market power is sufficiently concentrated. The model predicts negative correlation between number of sellers and share of barter in sales. We also show that barter disappears at certain level of concentration. Using survey data on Russian firms, we show that empirical evidence is consistent with predictions of the model. Sergei Guriev, Ph.D.
Optical surface modes in the presence of nonlinearity and disorder
We investigate numerically the effect of the competition of disorder,
nonlinearity, and boundaries on the Anderson localization of light waves in
finite-size, one-dimensional waveguide arrays. Using the discrete Anderson -
nonlinear Schr\"odinger equation, the propagation of the mode amplitudes up to
some finite distance is monitored. The analysis is based on the calculated
localization length and the participation number, two standard measures for the
statistical description of Anderson localization. For relatively weak disorder
and nonlinearity, a higher disorder strength is required to achieve the same
degree of localization at the edge than in the interior of the array, in
agreement with recent experimental observations in the linear regime. However,
for relatively strong disorder and/or nonlinearity, this behavior is reversed
and it is now easier to localize an excitation at the edge than in the
interior.Comment: 5 double-column pages, 7 figures, submitted for publicatio
Number squeezed and fragmented states of strongly interacting bosons in a double well
We present a systematic study of the phenomena of number squeezing and
fragmentation for a repulsive Bose-Einstein condensate (BEC) in a three
dimensional double well potential over a range of interaction strengths and
barrier heights, including geometries that exhibit appreciable overlap in the
one-body wavefunctions localized in the left and right wells. We compute the
properties of the condensate with numerically exact, full dimensional path
integral ground state (PIGS) Quantum Monte Carlo simulations and compare with
results obtained from using two- and eight-mode truncated basis models. The
truncated basis models are found to agree with the numerically exact PIGS
simulations for weak interactions, but fail to correctly predict the amount of
number squeezing and fragmentation exhibited by the PIGS simulations for strong
interactions. We find that both number squeezing and fragmentation of the BEC
show non-monotonic behavior at large values of interaction strength a. The
number squeezing shows a universal scaling with the product of number of
particles and interaction strength (Na) but no such universal behavior is found
for fragmentation. Detailed analysis shows that the introduction of repulsive
interactions not only suppresses number fluctuations to enhance number
squeezing, but can also enhance delocalization across wells and tunneling
between wells, each of which may suppress number squeezing. This results in a
dynamical competition whose resolution shows a complex dependence on all three
physical parameters defining the system: interaction strength, number of
particles, and barrier height.Comment: 33 pages, 21 figures. Submitted for publication in Physical Review
Giant photon gain in large-scale quantum dot circuit-QED systems
Motivated by recent experiments on the generation of coherent light in
engineered hybrid quantum systems, we investigate gain in a microwave photonic
cavity coupled to quantum dot structures, and develop concrete directions for
achieving a giant amplification in photon transmission. We propose two
architectures for scaling up the electronic gain medium: (i) double quantum
dot systems (N-DQD), (ii) quantum dots arranged in series akin to a quantum
cascade laser setup. In both setups, the fermionic reservoirs are voltage
biased, and the quantum dots are coupled to a single-mode cavity. Optical
amplification is explained based on a sum rule for the transmission function,
and it is determined by an intricate competition between two different
processes: charge density response in the gain medium, and cavity losses to
input and output ports. The same design principle is also responsible for the
corresponding giant amplification in other photonic observables, mean photon
number and emission spectrum, thereby realizing a quantum device that behaves
as a giant microwave amplifier.Comment: 6 pages, 5 figure
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