14,016 research outputs found
Collins-Soper Equation for the Energy Evolution of Transverse-Momentum and Spin Dependent Parton Distributions
The hadron-energy evolution (Collins and Soper) equation for all the
leading-twist transverse-momentum and spin dependent parton distributions is
derived in the impact parameter space. Based on the result, we present
resummation formulas for the spin structure functions in the semi-inclusive
deep inelastic scattering.Comment: 16 pages, 4 figures included, revised versio
Threshold Resummation for Higgs Production in Effective Field Theory
We present an effective field theory to resum the large double logarithms
originated from soft-gluon radiations at small final-state hadron invariant
masses in Higgs and vector boson (\gamma^*, and ) production at hadron
colliders. The approach is conceptually simple, indepaendent of details of an
effective field theory formulation, and valid to all orders in sub-leading
logarithms. As an example, we show the result of summing the
next-to-next-to-next leading logarithms is identical to that of standard pQCD
factorization method.Comment: A version to appear in Phys. Rev.
The relationship between two flavors of oblivious transfer at the quantum level
Though all-or-nothing oblivious transfer and one-out-of-two oblivious
transfer are equivalent in classical cryptography, we here show that due to the
nature of quantum cryptography, a protocol built upon secure quantum
all-or-nothing oblivious transfer cannot satisfy the rigorous definition of
quantum one-out-of-two oblivious transfer.Comment: 4 pages, no figur
Multimode laser cooling and ultra-high sensitivity force sensing with nanowires
Photo-induced forces can be used to manipulate and cool the mechanical motion
of oscillators. When the oscillator is used as a force sensor, such as in
atomic force microscopy, active feedback is an enticing route to enhancing
measurement performance. Here, we show broadband multimode cooling of dB
down to a temperature of ~K in the stationary regime. Through the use
of periodic quiescence feedback cooling, we show improved signal-to-noise
ratios for the measurement of transient signals. We compare the performance of
real feedback to numerical post-processing of data and show that both methods
produce similar improvements to the signal-to-noise ratio of force
measurements. We achieved a room temperature force measurement sensitivity of
N with integration time of less than ms. The high
precision and fast force microscopy results presented will potentially benefit
applications in biosensing, molecular metrology, subsurface imaging and
accelerometry.Comment: 16 pages and 3 figures for the main text, 14 pages and 5 figures for
the supplementary informatio
Identifying and Measuring the Effect of Firm Clusters Among Certified Organic Processors and Handlers
This paper investigates the certified organic handler sector, a specialized component of the middle part of the farm-to-table marketing chain, and documents the impacts of firm agglomeration (or firm clusters) on firm-level performance or firm-level decisions. After accounting for endogeneity in firm clustering, our findings confirm that firm clusters have significant impacts, though the estimate of the impact depends on how a firm cluster is defined. For example, significant impacts on sales per employee range from an additional 1.47 million, depending on whether a small or large number of firms is used as the minimum number to define a firm cluster.firm clusters, organic, treatment effects, Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development,
A Bose-Einstein condensate in a random potential
An optical speckle potential is used to investigate the static and dynamic
properties of a Bose-Einstein condensate in the presence of disorder. For
strong disorder the condensate is localized in the deep wells of the potential.
With smaller levels of disorder, stripes are observed in the expanded density
profile and strong damping of dipole and quadrupole oscillations is seen.
Uncorrelated frequency shifts of the two modes are measured for a weak disorder
and are explained using a sum-rules approach and by the numerical solution of
the Gross-Pitaevskii equation
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