417 research outputs found
Monetary Policy Targeting in Argentina and Canada in the 1990s: A Comparison, Some Contrasts, and a Tentative Evaluation
There are two generally accepted ways of plotting the aggregate demand (AD) and aggregate supply (AS) curves in the goods market. One puts the price level on the vertical axis (the P - y approach); the other plots the real interest rate on the vertical axis (the r - y approach). This paper develops the theoretical connections between these two approaches that permit one to tell a coherent dynamic story with the AD-AS model and also explores the conditions under which one approach or the other yields greater insight into the working of the model.Monetary Policy; Monetary; Policy
Entanglement, Dephasing, and Phase Recovery via Cross-Correlation Measurements of Electrons
Determination of the path taken by a quantum particle leads to a suppression
of interference and to a classical behavior. We employ here a quantum 'which
path' detector to perform accurate path determination in a
two-path-electron-interferometer; leading to full suppression of the
interference. Following the dephasing process we recover the interference by
measuring the cross-correlation between the interferometer and detector
currents. Under our measurement conditions every interfering electron is
dephased by approximately a single electron in the detector - leading to mutual
entanglement of approximately single pairs of electrons.Comment: 13 Pages, 5 Figure
Low level Îł-ray germanium-spectrometer to measure very low primordial radionuclide concentrations
Abstract A new germanium spectrometer especially suited for large sample measurements is described in detail. It is operated in the Gran Sasso underground laboratory under shielding rock of 3300 m water equivalent, which reduces the muon flux by six orders of magnitude. The integral background counting rate in the energy range from 50 to 2750 keV is about 0.15 minâ1. The low peak count rates of mostly less than 1 count per day together with a relative efficiency of 102% and the high sample capacity makes this spectrometer one of the most sensitive worldwide. Some sample measurements for the solar neutrino experiment BOREXINO and the detector efficiency calibration by the Monte Carlo method are discussed as well
Coarse-Grained Simulations of Membranes under Tension
We investigate the properties of membranes under tension by Monte-Carlo
simulations of a generic coarse-grained model for lipid bilayers. We give a
comprising overview of the behavior of several membrane characteristics, such
as the area per lipid, the monolayer overlap, the nematic order, and pressure
profiles. Both the low-temperature regime, where the membranes are in a gel
phase, and the high-temperature regime, where they are in the fluid phase, are
considered. In the gel state, the membrane is hardly influenced by tension. In
the fluid state, high tensions lead to structural changes in the membrane,
which result in different compressibility regimes. The ripple state, which is
found at tension zero in the transition regime between the fluid and the gel
phase, disappears under tension and gives way to an interdigitated phase. We
also study the membrane fluctuations in the fluid phase. In the low tension
regime the data can be fitted nicely to a suitably extended elastic theory. At
higher tensions the elastic fit consistently underestimates the strength of
long-wavelength fluctuations. Finally, we investigate the influence of tension
on the effective interaction between simple transmembrane inclusions and show
that tension can be used to tune the hydrophobic mismatch interaction between
membrane proteins.Comment: 14 pages, 14 figures, accepted for publication in The Journal of
Chemical Physic
Controlled Dephasing of Electrons by Non-Gaussian Shot Noise
In a 'controlled dephasing' experiment [1-3], an interferometer loses its
coherence due to entanglement with a controlled quantum system ('which path'
detector). In experiments that were conducted thus far in mesoscopic systems
only partial dephasing was achieved. This was due to weak interactions between
many detector electrons and the interfering electron, resulting in a Gaussian
phase randomizing process [4-10]. Here, we report the opposite extreme: a
complete destruction of the interference via strong phase randomization only by
a few electrons in the detector. The realization was based on interfering edge
channels (in the integer quantum Hall effect regime, filling factor 2) in a
Mach-Zehnder electronic interferometer, with an inner edge channel serving as a
detector. Unexpectedly, the visibility quenched in a periodic lobe-type form as
the detector current increased; namely, it periodically decreased as the
detector current, and thus the detector's efficiency, increased. Moreover, the
visibility had a V-shape dependence on the partitioning of the detector
current, and not the expected dependence on the second moment of the shot
noise, T(1-T), with T the partitioning. We ascribe these unexpected features to
the strong detector-interferometer coupling, allowing only 1-3 electrons in the
detector to fully dephase the interfering electron. Consequently, in this work
we explored the non-Gaussian nature of noise [11], namely, the direct effect of
the shot noise full counting statistics [12-15].Comment: 14 pages, 4 figure
Current-voltage correlations in interferometers
We investigate correlations of current at contacts and voltage fluctuations
at voltage probes coupled to interferometers. The results are compared with
correlations of current and occupation number fluctuations at dephasing probes.
We use a quantum Langevin approach for the average quantities and their
fluctuations. For higher order correlations we develop a stochastic path
integral approach and find the generating functions of voltage or occupation
number fluctuations. We also derive a generating function for the joint
distribution of voltage or occupation number at the probe and current
fluctuations at a terminal of a conductor. For energy independent scattering we
found earlier that the generating function of current cumulants in
interferometers with a one-channel dephasing or voltage probe are identical.
Nevertheless, the distribution function for voltage and the distribution
function for occupation number fluctuations differ, the latter being broader
than that of former in all examples considered here.Comment: 23 pages, 10 figures, minor changes, additional appendix, added
reference
Fermionic Mach-Zehnder interferometer subject to a quantum bath
We study fermions in a Mach-Zehnder interferometer, subject to a
quantum-mechanical environment leading to inelastic scattering, decoherence,
renormalization effects, and time-dependent conductance fluctuations. Both the
loss of interference contrast as well as the shot noise are calculated, using
equations of motion and leading order perturbation theory. The full dependence
of the shot-noise correction on setup parameters, voltage, temperature and the
bath spectrum is presented. We find an interesting contribution due to
correlations between the fluctuating renormalized phase shift and the output
current, discuss the limiting behaviours at low and high voltages, and compare
with simpler models of dephasing.Comment: 5 pages, 3 figure
Seleção precoce de famĂlias de irmĂŁos-completos de batata.
Clonal selection is the preferred breeding method used in potatoes (Solanum tuberosum L.). However this selection procedure is only efficient for more advanced generations and shows no good results when applied in the seedling up to the second clonal generation. This study assessed the feasibility of selection in early generations of full-sib potato families and compares the selection method among and within families with the combined selection under different selection intensities. Six experiments were conducted from the first (C1) until the third clonal generation (C3). In C1 a randomized complete block design with four replications of 25 plants was used. In the remaining generations RCB was employed with three replications of 10 plants. Genetic variances were lower between families than within families, for all traits, but the heritabilities between families were almost always larger. The expected gains from selection between and within families were superior to gains from the combined selection in any intensity of selection. The selection of families should have weaker intensity than selection among clones within families. The selection of families was more efficient when based on the average of environments
Single electron quantum tomography in quantum Hall edge channels
We propose a quantum tomography protocol to measure single electron coherence
in quantum Hall edge channels and therefore access for the first time the wave
function of single electron excitations propagating in ballistic quantum
conductors. Its implementation would open the way to quantitative studies of
single electron decoherence and would provide a quantitative tool for analyzing
single to few electron sources. We show how this protocol could be implemented
using ultrahigh sensitivity noise measurement schemes.Comment: Version 3: long version (7 figures): corrections performed and
references have been added. Figures reprocessed for better readabilit
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