Universal Correlations of Coulomb Blockade Conductance Peaks and the Rotation Scaling in Quantum Dots

We show that the parametric correlations of the conductance peak amplitudes of a chaotic or weakly disordered quantum dot in the Coulomb blockade regime become universal upon an appropriate scaling of the parameter. We compute the universal forms of this correlator for both cases of conserved and broken time reversal symmetry. For a symmetric dot the correlator is independent of the details in each lead such as the number of channels and their correlation. We derive a new scaling, which we call the rotation scaling, that can be computed directly from the dot's eigenfunction rotation rate or alternatively from the conductance peak heights, and therefore does not require knowledge of the spectrum of the dot. The relation of the rotation scaling to the level velocity scaling is discussed. The exact analytic form of the conductance peak correlator is derived at short distances. We also calculate the universal distributions of the average level width velocity for various values of the scaled parameter. The universality is illustrated in an Anderson model of a disordered dot.Comment: 35 pages, RevTex, 6 Postscript figure

The BCS-Bose Crossover Theory

We contrast {\it four} distinct versions of the BCS-Bose statistical crossover theory according to the form assumed for the electron-number equation that accompanies the BCS gap equation. The four versions correspond to explicitly accounting for two-hole-(2h) as well as two-electron-(2e) Cooper pairs (CPs), or both in equal proportions, or only either kind. This follows from a recent generalization of the Bose-Einstein condensation (GBEC) statistical theory that includes not boson-boson interactions but rather 2e- and also (without loss of generality) 2h-CPs interacting with unpaired electrons and holes in a single-band model that is easily converted into a two-band model. The GBEC theory is essentially an extension of the Friedberg-T.D. Lee 1989 BEC theory of superconductors that excludes 2h-CPs. It can thus recover, when the numbers of 2h- and 2e-CPs in both BE-condensed and noncondensed states are separately equal, the BCS gap equation for all temperatures and couplings as well as the zero-temperature BCS (rigorous-upper-bound) condensation energy for all couplings. But ignoring either 2h- {\it or} 2e-CPs it can do neither. In particular, only {\it half} the BCS condensation energy is obtained in the two crossover versions ignoring either kind of CPs. We show how critical temperatures $T_{c}$ from the original BCS-Bose crossover theory in 2D require unphysically large couplings for the Cooper/BCS model interaction to differ significantly from the $T_{c}$s of ordinary BCS theory (where the number equation is substituted by the assumption that the chemical potential equals the Fermi energy).Comment: thirteen pages including two figures. Physica C (in press, 2007

Weakly-Bound Three-Body Systems with No Bound Subsystems

We investigate the domain of coupling constants which achieve binding for a 3-body system, while none of the 2-body subsystems is bound. We derive some general properties of the shape of the domain, and rigorous upper bounds on its size, using a Hall--Post decomposition of the Hamiltonian. Numerical illustrations are provided in the case of a Yukawa potential, using a simple variational method.Comment: gzipped ps with 11 figures included. To appear in Phys. Rev.

Chronic Hepatitis C treatment for genotype 2 or 3 in Brazil: cost effectiveness analysis of peginterferon plus ribavirin as first choice treatment

Brazilian Guidelines to HCV treatment (2007) recommended that the first choice treatment for patients with chronic hepatitis C (CHC) and genotype 2 or 3 is interferon alpha (IFN) plus ribavirin (RBV) for 24 weeks. The aim of this study is compare the cost and effectiveness to Hepatitis C treatment in patients with genotype 2 or 3 of peginterferon alpha (PEG) as the first choice of treatment within PEG for those that do not respond to IFN. The target population is CHC patients with genotype 2 or 3 in Brazil. The interventions are: PEG-SEC (first IFN plus RBV for 24 weeks, after, for non-responders and relapsers subsequently PEG plus RBV for 48 weeks); PEG-FIRST24 (PEG+RBV for 24 weeks). The type of the study is cost-effectiveness analysis. The data sources are: Effectiveness data from meta-analysis conducted on the Brazilian population. Treatment cost from Brazilian micro costing study is converted into USD (2010). The perspective is the Public Health System. The outcome measurements are Sustained Viral Response (SVR) and costs. PEG-FIRST24 (SVR: 87.8%, costs: USD 8,338.27) was more effective and more costly than PEG-SEC (SVR: 79.2%, costs: USD 5,852.99). The sensitivity analyses are: When SVR rates with IFN was less than 30% PEG-FIRST is dominant. On the other hand, when SVR with IFN was more then 75% PEG-SEC is dominant (SVR=88.2% and costs USD $ 3,753.00). PEG-SEC is also dominant when SVR to PEG24 weeks was less than 54%. In the Brazilian context, PEG-FIRST is more effective and more expensive than PEG-SEC. PEG-SEC could be dominant when rates of IFN therapy are higher than 75% or rates of PEG24 therapy are lower than 54%

Hadronic Structure in the Decay τ−→π−π0ντ\tau^{-}\to \pi^{-}\pi^{0}\nu_{\tau}

We report on a study of the invariant mass spectrum of the hadronic system in the decay tau- -> pi- pi0 nu_tau. This study was performed with data obtained with the CLEO II detector operating at the CESR e+ e- collider. We present fits to phenomenological models in which resonance parameters associated with the rho(770) and rho(1450) mesons are determined. The pi- pi0 spectral function inferred from the invariant mass spectrum is compared with data on e+ e- -> pi+ pi- as a test of the Conserved Vector Current theorem. We also discuss the implications of our data with regard to estimates of the hadronic contribution to the muon anomalous magnetic moment.Comment: 39 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Transport properties in dilute alloys

Recent theoretical and experimental progress relating to transport properties in dilute alloys is reviewed, with particular attention paid to the value of conventional transport measurements in providing information on the electronic band structure of alloys.On passe en revue, aussi bien dans le domaine théorique qu'expérimental, les progrès réalisés dans l'étude des propriétés de transport des alliages dilués ; on porte une attention particulière aux valeurs obtenues dans les mesures classiques de ces propriétés en vue d'en tirer des informations sur la structure de bande des alliages