106,695 research outputs found
Intra pseudogap- and superconductivity-pair spin and charge fluctuations and underdome metal-insulator (fermion-boson)-crossover phenomena as keystones of cuprate physics
The most intriguing observation of cuprate experiments is most likely the
metal-insulator-crossover (MIC), seen in the underdome region of the
temperature-doping phase diagram of copper-oxides under a strong magnetic
field, when the superconductivity is suppressed. This MIC, which results in
such phenomena as heat conductivity downturn, anomalous Lorentz ratio,
nonlinear entropy, insulating ground state, nematicity- and stripe-phases and
Fermi pockets, reveals the nonconventional dielectric property of the
pseudogap-normal phase. Since conventional superconductivity appears from a
conducting normal phase, the understanding of how superconductivity arises from
an insulating state becomes a fundamental problem and thus the keystone for all
of cuprate physics. Recently, in interpreting the physics of visualization in
scanning tunneling microscopy (STM) real space nanoregions (NRs), which exhibit
an energy gap, we have succeeded in understanding that the minimum size for
these NRs provides pseudogap and superconductivity pairs, which are single
bosons. In this work, we discuss the intra-particle magnetic spin and charge
fluctuations of these bosons, observed recently in hidden magnetic order and
STM experiments. We find that all the mentioned MIC phenomena can be obtained
in the Coulomb single boson and single fermion two liquid model, which we
recently developed, and the MIC is a crossover of sample percolating NRs of
single fermions into those of single bosons.Comment: 22 pages, 7 figures. arXiv admin note: text overlap with
arXiv:1010.043
Scratching the Bose surface
This is a `News and Views' article discussing recent proposals for ground
states of many boson systems which are neither superfluids nor Mott insulators.Comment: 4 pages, 1 figur
Precision polarimetry with real-time mitigation of optical-window birefringence
Optical-window birefringence is frequently a major obstacle in experiments
measuring changes in the polarization state of light traversing a sample under
investigation. It can contribute a signal indistinguishable from that due to
the sample and complicate the analysis. Here, we explore a method to measure
and compensate for the birefringence of an optical window using the reflection
from the last optical surface before the sample. We demonstrate that this
arrangement can cancel out false signals due to the optical-window
birefringence-induced ellipticity drift to about 1%, for the values of total
ellipticity less than 0.25 rad
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Assessing the potential economic benefits to farmers from various GM crops becoming available in the European Union by 2025: results from an expert survey
This paper reports on a study that identified a range of crop-trait combinations that are: agronomically suited to the EU; provide advantages to arable farmers and consumers; and are either already available in international markets, or advancing along the development pipeline and likely to become available by 2025. An expert stakeholder panel was recruited and asked for their views, using the Delphi approach, on the impact of these crop-traits on enterprise competitiveness, through changes to yields, production costs and product prices. In terms of input traits, there was consensus that traits such as herbicide tolerant/insect resistant (HT/IR) maize, HT sugar beet and HT soya bean would provide positive benefits for farmers. Output-side traits such as winter-sown rape with reduced saturated fats, were seen as offering benefits to consumers, but were either likely to be restricted to niche markets, or offer relatively modest price premia to farmers growing them. Our analysis of the financial impact of the adoption of GM crops more widely in the EU, showed that the competitiveness of the agricultural sector could well be improved by this. However, such improvements would be relatively small-scale in that large-scale national natural advantages from either economic or environmental conditions is unlikely to be overturned
A technique for constructing spectral reflectance curves from Viking lander camera multispectral data
A technique for evaluating the construction of spectral reflectance curves from multispectral data obtained with the Viking lander cameras is presented. The multispectral data is limited to 6 channels in the wave-length range 0.4 to 1.1 microns, and several of the channels suffer from appreciable out-of-band response. The technique represents the estimated reflectance curves as a linear combination of known basic functions with coefficients determined to minimize the error in the representation, and it permits all channels, with and without out-of-band response, to contribute equally valid information. The technique is evaluated for known spectral reflectance curves of 8 materials felt likely to be present on the Martian surface. The technique provides an essentially exact fit if the the reflectance curve has no pronounced maxima and minima. Even if the curve has pronounced maxima and minima, the fit is good and reveals the most dominant features. Since only 6 samples are available some short period features are lost. This loss is almost certainly due to undersampling rather than out-of-band channel response
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