SET based experiments for HTSC materials: II

The cuprates seem to exhibit statistics, dimensionality and phase transitions in novel ways. The nature of excitations [i.e. quasiparticle or collective], spin-charge separation, stripes [static and dynamics], inhomogeneities, psuedogap, effect of impurity dopings [e.g. Zn, Ni] and any other phenomenon in these materials must be consistently understood. In this note we further discuss our original suggestion of using Single Electron Tunneling Transistor [SET] based experiments to understand the role of charge dynamics in these systems. Assuming that SET operates as an efficient charge detection system we can expect to understand the underlying physics of charge transport and charge fluctuations in these materials for a range of doping. Experiments such as these can be classed in a general sense as mesoscopic and nano characterization of cuprates and related materials. In principle such experiments can show if electron is fractionalized in cuprates as indicated by ARPES data. In contrast to flux trapping experiments SET based experiments are more direct in providing evidence about spin-charge separation. In addition a detailed picture of nano charge dynamics in cuprates may be obtained.Comment: 10 pages revtex plus four figures; ICMAT 2001 Conference Symposium P: P10-0

Parameters for Systems Exhibiting Local Lattice Distortions, Charge and Spin Ordering

Keeping in mind the experimental results that indicate local lattice distortions, charge and spin orderings, we have developed a phenomenological approach which allows us to describe the electronic phase diagram of cuprates and related systems in terms of few parameters.In the present work we consider a third-order parameter theory which characterize charge, spin and superconductivity orderings. We are thus led to a theory of three scalar fields. By coupling these scalars to gauge fields we are naturally led to string-like solutions, which we interpret as stripes. This ties nicely with our quantum group conjecture that 1d systems play an important role in the physics of cuprates and related materials. We show that this simple approach can give rough values for two-order parameters which can be naively be interpreted as charge and spin orderings. We also report our attempt to understand how local lattice distortions are involved and what role they play in terms of these two order parameters.Comment: 8 pages revtex, Published in AIP Conference Proceedings 554: Int. Sym. on Physics in Local Lattice Distortions, July 23-26, 200

Search for lepton flavor violation via the intense high-energy muon beam

A deep inerastic scattering process \mutau is discussed to study lepton flavor violation between muons and tau leptons. In supersymmetric models, the Higgs boson mediated diagrams could be important for this reaction. We find that at a muon energy ($E_{\mu}$) higher than 50 GeV, the predicted cross section significantly increases due to the contribution from sea $b$-quarks. The number of produced tau leptons can be $\mathcal{O}(10^4)$ at $E_{\mu}$= 300 GeV from $10^{20}$ muons, whereas $\mathcal{O}(10^2)$ events are given at $E_{\mu}= 50$ GeV.Comment: Contribution to the 6th International Workshop on Neutrino Factories & Superbeams(NuFact04), Jul. 26-Aug. 1, 2004, Osaka Univerisity, Osaka, Japan, talk given by S.K., to appear in the Proceedings, 3 pages, 4 figure

A critical analysis of COA research.

Five experts respected for their significant contributions to the scientific literature on children of alcoholics (COA's) offer their perspectives in a panel discussion format. The panel members reflect on the historical roots of COA research and comment on its current status and future direction. Enriched by the panelists' variety of backgrounds, research interests, and approaches, the discussion emphasizes the need to consider multiple variables that influence the risk for alcoholism among COA's

Heat Capacity study of β\beta-FeSi2_2 single crystals

Heat Capacity of needle-like [length=5mm, diameter=1 mm] $\beta$-FeSi$_{2}$ single crystal, grown by chemical vapor transport has been measured. Two anomalies are found, a broad deviation centered around 160 K and a clear deviation at a temperature of 255 K approximately. We have attempted to relate these to the anomalies previously reported in the case of the resistivity data. The Transient Thermoelectric Effect [TTE] results lead us to the inference that the system under goes from single carrier system to at least two carrier system at 220 K-our heat capacity results seem to provide further independent evidence for this transition in this system.Comment: 8 pages, 5 figure

Combined analysis of microbial metagenomic and metatranscriptomic sequencing data to assess in situ physiological conditions in the premature infant gut.

Microbes alter their transcriptomic profiles in response to the environment. The physiological conditions experienced by a microbial community can thus be inferred using meta-transcriptomic sequencing by comparing transcription levels of specifically chosen genes. However, this analysis requires accurate reference genomes to identify the specific genes from which RNA reads originate. In addition, such an analysis should avoid biases in transcript counts related to differences in organism abundance. In this study we describe an approach to address these difficulties. Sample-specific meta-genomic assembled genomes (MAGs) were used as reference genomes to accurately identify the origin of RNA reads, and transcript ratios of genes with opposite transcription responses were compared to eliminate biases related to differences in organismal abundance, an approach hereafter named the "diametric ratio" method. We used this approach to probe the environmental conditions experienced by Escherichia spp. in the gut of 4 premature infants, 2 of whom developed necrotizing enterocolitis (NEC), a severe inflammatory intestinal disease. We analyzed twenty fecal samples taken from four premature infants (4-6 time points from each infant), and found significantly higher diametric ratios of genes associated with low oxygen levels in samples of infants later diagnosed with NEC than in samples without NEC. We also show this method can be used for examining other physiological conditions, such as exposure to nitric oxide and osmotic pressure. These study results should be treated with caution, due to the presence of confounding factors that might also distinguish between NEC and control infants. Nevertheless, together with benchmarking analyses, we show here that the diametric ratio approach can be applied for evaluating the physiological conditions experienced by microbes in situ. Results from similar studies can be further applied for designing diagnostic methods to detect NEC in its early developmental stages

Physics 201: Modern Physics

Following the spirit of the new curriculum, it was decided to convert the Modern Physics course, Physics 201, into a course with a COLL200 attribute. The course covered the basics of relativity and quantum mechanics, and typically has 50-60 students. It was desired to include a substantial discussion of the historical and social significance of the material