2,739 research outputs found
Spin Fluctuations and the Pseudogap in Organic Superconductors
We show that there are strong similarities in the spin lattice relaxation of
non-magnetic organic charge transfer salts, and that these similarities can be
understood in terms of spin fluctuations. Further, we show that, in all of the
kappa-phase organic superconductors for which there is nuclear magnetic
resonance data, the energy scale for the spin fluctuations coincides with the
energy scale for the pseudogap. This suggests that the pseudogap is caused by
short-range spin correlations. In the weakly frustrated metals
k-(BEDT-TTF)_2Cu[N(CN)_2]Br, k-(BEDT-TTF)_2Cu(NCS)_2, and
k-(BEDT-TTF)_2Cu[N(CN)_2]Cl (under pressure) the pseudogap opens at the same
temperature as coherence emerges in the (intralayer) transport. We argue that
this is because the spin correlations are cut off by the loss of intralayer
coherence at high temperatures. We discuss what might happen to these two
energy scales at high pressures, where the electronic correlations are weaker.
In these weakly frustrated materials the data is well described by the chemical
pressure hypothesis (that anion substitution is equivalent to hydrostatic
pressure). However, we find important differences in the metallic state of
k-(BEDT-TTF)_2Cu_2(CN)_3, which is highly frustrated and displays a spin liquid
insulating phase. We also show that the characteristic temperature scale of the
spin fluctuations in (TMTSF)_2ClO_4 is the same as superconducting critical
temperature, which may be evidence that spin fluctuations mediate the
superconductivity in the Bechgaard salts.Comment: 7 pages, 4 figures; to appear in PR
A Wire Position Monitor System for the 1.3 GHZ Tesla-Style Cryomodule at the Fermilab New-Muon-Lab Accelerator
The first cryomodule for the beam test facility at the Fermilab New-Muon-Lab
building is currently under RF commissioning. Among other diagnostics systems,
the transverse position of the helium gas return pipe with the connected 1.3
GHz SRF accelerating cavities is measured along the ~15 m long module using a
stretched-wire position monitoring system. An overview of the wire position
monitor system technology is given, along with preliminary results taken at the
initial module cool down, and during further testing. As the measurement system
offers a high resolution, we also discuss options for use as a vibration
detector.Comment: 4 pp. 15th International Conference on RF Superconductivity
(SRF2011). 25-29 Jul 2011. Chicago, Illinois, US
Inovasi dan Data Elektronik untuk Posyandu Kelurahan Caringin Kota Bandung
Posyandu merupakan suatu Usaha Kesehatan Berbasis Masyarakat yang dijalankan oleh relawandengan bimbingan dari perangkat kelurahan. Saat ini salah satu kegiatan utama yang dijalankan adalahpenimbangan bayi sebagai USAha untuk mengurangi tingkat kematian ibu dan bayi. Penimbangan bayi inidilakukan dengan menggunakan alat timbang gantung geser yang rentan terhadap kesalahan pembacaankarena bergerak-gerak. Selain itu pencatatan masih manual ke buku register yang juga rentan padakesalahan penulisan ulang dan perlu waktu lebih lama untuk rekapitulasi di kantor kelurahan.Pada penelitian ini diajukan inovasi pelaksanaan kegiatan dan implementasi data elektronik untukposyandu di Kelurahan Caringin, Kecamatan Bandung Kulon, Kota Bandung. Pengukuran berat Balitadibantu oleh alat timbang digital dengan resolusi yang diperlukan. Data bisa langsung tercatat di perangkatgenggam. Dengan bantuan Open Data Kit Collect data bisa disimpan sebelum diunggah ke Open Data KitAggregate server setelah ada koneksi internet. Perangkat kelurahan diharapkan bisa mendesain borangpencatatan dan menganalisa data hasil pencatatan Open Data Kit
High Resolution BPM Upgrade for the ATF Damping Ring at KEK
A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility
(ATF) damping ring has been accomplished, carried out by a KEK/FNAL/SLAC
collaboration under the umbrella of the global ILC R&D effort. The upgrade
consists of a high resolution, high reproducibility read-out system, based on
analog and processing, and also implements a new automatic gain error
correction schema. The technical concept and realization as well as results of
beam studies are presented.Comment: 3 pp. 10th European Workshop on Beam Diagnostics and Instrumentation
for Particle Accelerators DIPAC 2011, 16-18 May 2011. Hamburg, German
Effect of Global Warming Scenarios on Carotenoid Pigments Gracilaria changii
The phenomenon of global warming is an increase in the earth's temperature due to the greenhouse effect where 50% of the main contributors to the greenhouse effect are carbon dioxide (CO2). Carbon dioxide is one of the ingredients needed for photosynthesis. Photosynthesis is carried out by plants that have chloroplasts. Plants in the waters are Seaweed. Gracilaria changii is a type of red seaweed (Rhodophyceae). The dominant pigment from Gracilaria changii is carotenoids. Carotenoid serves as a light energy absorbent for photosynthesis and serves to protect chlorophyll from light damage. Seeing the important role of carotenoids in Gracilaria changii so that this study aims to determine the effect of increasing temperature and carbon dioxide on carotenoid pigments. Research on the scenario of global warming in this region was first carried out on a laboratory scale, many previous studies were carried out in the cultivation area. This study was conducted for 40 days, seaweed that has been cleaned is put into an aquarium and given an injection of CO2. We were exposed to present-day control seawater (400 ppm pCO2 ) and seawater treated with CO2 to simulate ocean conditions predicted for the next 50–100 years (700 ppm, 1000 ppm, and 1300 ppm) and temperature treatment (30 oC, 32 oC, 34 oC). The research design applied in this study is a Completely Randomized Design consisting of nine treatments with three replications. Data analysis used is Analysis of Variance (ANOVA) continued by Post hoc Test. The results obtained from this study there were significant differences (
Auxiliary field approach to dilute Bose gases with tunable interactions
We rewrite the Lagrangian for a dilute Bose gas in terms of auxiliary fields
related to the normal and anomalous condensate densities. We derive the loop
expansion of the effective action in the composite-field propagators. The
lowest-order auxiliary field (LOAF) theory is a conserving mean-field
approximation consistent with the Goldstone theorem without some of the
difficulties plaguing approximations such as the Hartree and Popov
approximations. LOAF predicts a second-order phase transition. We give a set of
Feynman rules for improving results to any order in the loop expansion in terms
of composite-field propagators. We compare results of the LOAF approximation
with those derived using the Popov approximation. LOAF allows us to explore the
critical regime for all values of the coupling constant and we determine
various parameters in the unitarity limit.Comment: 16 pages, 7 figure
Fusion products, Kostka polynomials, and fermionic characters of su(r+1)_k
Using a form factor approach, we define and compute the character of the
fusion product of rectangular representations of \hat{su}(r+1). This character
decomposes into a sum of characters of irreducible representations, but with
q-dependent coefficients. We identify these coefficients as (generalized)
Kostka polynomials. Using this result, we obtain a formula for the characters
of arbitrary integrable highest-weight representations of \hat{su}(r+1) in
terms of the fermionic characters of the rectangular highest weight
representations.Comment: 21 pages; minor changes, typos correcte
- …