10,340 research outputs found
Why weak patents? Rational ignorance or pro-"customer" Tilt?
The issuance of weak patents is widely viewed as a fundamental problem in the current US patent system. Reasons that have been offered for the granting of weak patents by the US Patent and Trademark Office (USPTO) include examinersâ ârational ignoranceâ of the patentability of applications and pro-âcustomerâ rules and institutions that create incentives for examiners to grant patents of dubious validity to their âcustomersâ- applicants. In this paper, we study whether US examinersâ behavior in prior art search betrays their assessment of applicationsâ patentability. For a sample of US patents for which applications were also filed at the European Patent Office (EPO), we construct a measure of the fraction of prior art that is missed by US examiners. We find that this measure significantly explains the probability of receiving a patent at the EPO. The results are robust to different empirical specifications. US examinersâ prior art searches indicate that they are, on average, not ârationally ignorantâ. On the contrary, they identify and dedicate more search effort to those applications that seem more problematic, because they bear the burden of proof of non-patentability. Our study offers empirical evidence that a systematic problem of weak patents likely exists, and suggests that the problem may be more strongly attributable to the pro-applicant rules and policies than to examinersâ ignorance. The current prevalence of weak patents does not appear to be caused at the margin by lack of resources at the USPTO.Weak patents, Rational ignorance, cited prior art, missed prior art, Industrial Organization, Institutional and Behavioral Economics, Research and Development/Tech Change/Emerging Technologies,
Non-Abelian Generalizations of the Hofstadter model: Spin-orbit-coupled Butterfly Pairs
The Hofstadter model, well-known for its fractal butterfly spectrum,
describes two-dimensional electrons under a perpendicular magnetic field, which
gives rise to the integer quantum hall effect. Inspired by the real-space
building blocks of non-Abelian gauge fields from a recent experiment [Science,
365, 1021 (2019)], we introduce and theoretically study two non-Abelian
generalizations of the Hofstadter model. Each model describes two pairs of
Hofstadter butterflies that are spin-orbit coupled. In contrast to the original
Hofstadter model that can be equivalently studied in the Landau and symmetric
gauges, the corresponding non-Abelian generalizations exhibit distinct spectra
due to the non-commutativity of the gauge fields. We derive the genuine
(necessary and sufficient) non-Abelian condition for the two models from the
commutativity of their arbitrary loop operators. At zero energy, the models are
gapless and host Weyl and Dirac points protected by internal and crystalline
symmetries. Double (8-fold), triple (12-fold), and quadrupole (16-fold) Dirac
points also emerge, especially under equal hopping phases of the non-Abelian
potentials. At other fillings, the gapped phases of the models give rise to
topological insulators. We conclude by discussing possible
schemes for the experimental realizations of the models in photonic platforms
Patents versus patenting: implications of intellectual property protection for biological research
A new survey shows scientists consider the proliferation of intellectual property protectionto have a strongly negative effect on research.patents, biology, intellectual property, material transfer agreements
Periodicities in the occurrence of aurora as indicators of solar variability
A compilation of records of the aurora observed in China from the Time of the Legends (2000 - 3000 B.C.) to the mid-18th century has been used to infer the frequencies and strengths of solar activity prior to modern times. A merging of this analysis with auroral and solar activity patterns during the last 200 years provides basically continuous information about solar activity during the last 2000 years. The results show periodicities in solar activity that contain average components with a long period (approx. 412 years), three middle periods (approx. 38 years, approx. 77 years, and approx. 130 years), and the well known short period (approx. 11 years)
Stable dilute supersolid of two-dimensional dipolar bosons
We consider two-dimensional bosonic dipoles oriented perpendicularly to the
plane. On top of the usual two-body contact and long-range dipolar interactions
we add a contact three-body repulsion as expected, in particular, for dipoles
in the bilayer geometry with tunneling. The three-body repulsion is crucial for
stabilizing the system, and we show that our model allows for stable continuous
space supersolid states in the dilute regime and calculate the zero-temperature
phase diagram.Comment: revised version, 5 pages, 2 figures, with 3 pages supplementary
materia
Topological Zero-Thickness Cosmic Strings
In this paper, based on the gauge potential decomposition and the
mapping theories, we study the topological structures and properties of
the cosmic strings that arise in the Abelian-Higgs gauge theory in the
zero-thickness limit. After a detailed discussion, we conclude that the
topological tensor current introduced in our model is a better and more basic
starting point than the generally used Nambu-Goto effective action for studying
cosmic strings.Comment: 10 pages, no figure
The Nature of the Interlayer Interaction in Bulk and Few-Layer Phosphorus
An outstanding challenge of theoretical electronic structure is the
description of van der Waals (vdW) interactions in molecules and solids.
Renewed interest in resolving this is in part motivated by the technological
promise of layered systems including graphite, transition metal
dichalcogenides, and more recently, black phosphorus, in which the interlayer
interaction is widely believed to be dominated by these types of forces. We
report a series of quantum Monte Carlo (QMC) calculations for bulk black
phosphorus and related few-layer phosphorene, which elucidate the nature of the
forces that bind these systems and provide benchmark data for the energetics of
these systems. We find a significant charge redistribution due to the
interaction between electrons on adjacent layers. Comparison to density
functional theory (DFT) calculations indicate not only wide variability even
among different vdW corrected functionals, but the failure of these functionals
to capture the trend of reorganization predicted by QMC. The delicate interplay
of steric and dispersive forces between layers indicate that few-layer
phosphorene presents an unexpected challenge for the development of vdW
corrected DFT.Comment: 8 pages, 6 figure
Fluctuation and localization of acoustic waves in bubbly water
Here the fluctuation properties of acoustic localization in bubbly water is
explored. We show that the strong localization can occur in such a system for a
certain frequency range and sufficient filling fractions of air-bubbles. Two
fluctuating quantities are considered, that is, the fluctuation of transmission
and the fluctuation of the phase of acoustic wave fields. When localization
occurs, these fluctuations tend to vanish, a feature able to uniquely identify
the phenomenon of wave localization.Comment: 10 pages, 4 figure
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