Electroneutrality and the Friedel sum rule in a Luttinger liquid

Screening in one-dimensional metals is studied for arbitrary electron-electron interactions. It is shown that for finite-range interactions (Luttinger liquid) electroneutrality is violated. This apparent inconsistency can be traced to the presence of external screening gates responsible for the effectively short-ranged Coulomb interactions. We also draw attention to the breakdown of linear screening for wavevectors close to 2 K_f.Comment: 4 pages REVTeX, incl one figure, to appear in Phys.Rev.Let

Magnetic tight-binding and the iron-chromium enthalpy anomaly

We describe a self consistent magnetic tight-binding theory based in an expansion of the Hohenberg-Kohn density functional to second order, about a non spin polarised reference density. We show how a first order expansion about a density having a trial input magnetic moment leads to the Stoner--Slater rigid band model. We employ a simple set of tight-binding parameters that accurately describes electronic structure and energetics, and show these to be transferable between first row transition metals and their alloys. We make a number of calculations of the electronic structure of dilute Cr impurities in Fe which we compare with results using the local spin density approximation. The rigid band model provides a powerful means for interpreting complex magnetic configurations in alloys; using this approach we are able to advance a simple and readily understood explanation for the observed anomaly in the enthalpy of mixing.Comment: Submitted to Phys Rev

Semiclassical expansion of parametric correlation functions of the quantum time delay

We derive semiclassical periodic orbit expansions for a correlation function of the Wigner time delay. We consider the Fourier transform of the two-point correlation function, the form factor $K(\tau,x,y,M)$, that depends on the number of open channels $M$, a non-symmetry breaking parameter $x$, and a symmetry breaking parameter $y$. Several terms in the Taylor expansion about $\tau=0$, which depend on all parameters, are shown to be identical to those obtained from Random Matrix Theory.Comment: 21 pages, no figure

Random Matrix Theory of Transition Strengths and Universal Magnetoconductance in the Strongly Localized Regime

Random matrix theory of the transition strengths is applied to transport in the strongly localized regime. The crossover distribution function between the different ensembles is derived and used to predict quantitatively the {\sl universal} magnetoconductance curves in the absence and in the presence of spin-orbit scattering. These predictions are confirmed numerically.Comment: 15 pages and two figures in postscript, revte

Resistivity due to low-symmetrical defects in metals

The impurity resistivity, also known as the residual resistivity, is calculated ab initio using multiple-scattering theory. The mean-free path is calculated by solving the Boltzmann equation iteratively. The resistivity due to low-symmetrical defects, such as an impurity-vacancy pair, is calculated for the FCC host metals Al and Ag and the BCC transition metal V. Commonly, 1/f noise is attributed to the motion of such defects in a diffusion process.Comment: 24 pages in REVTEX-preprint format, 10 Postscript figures. Phys. Rev. B, vol. 57 (1998), accepted for publicatio

The Strong Coupling Fixed-Point Revisited

In recent work we have shown that the Fermi liquid aspects of the strong coupling fixed point of the s-d and Anderson models can brought out more clearly by interpreting the fixed point as a renormalized Anderson model, characterized by a renormalized level $\tilde\epsilon_d$, resonance width, $\tilde\Delta$, and interaction $\tilde U$, and a simple prescription for their calculation was given using the numerical renormalization group (NRG). These three parameters completely specify a renormalized perturbation theory (RPT) which leads to exact expressions for the low temperature behaviour. Using a combination of the two techniques, NRG to determine $\tilde\epsilon_d$, $\tilde\Delta$, and $\tilde U$, and then substituting these in the RPT expressions gives a very efficient and accurate way of calculating the low temperature behaviour of the impurity as it avoids the necessity of subtracting out the conduction electron component. Here we extend this approach to an Anderson model in a magnetic field, so that $\tilde\epsilon_d$, $\tilde\Delta$, and $\tilde U$ become dependent on the magnetic field. The de-renormalization of the renormalized quasiparticles can then be followed as the magnetic field strength is increased. Using these running coupling constants in a RPT calculation we derive an expression for the low temperature conductivity for arbitrary magnetic field strength.Comment: Contribution to JPSJ volume commemorating the 40th anniversary of the publication of Kondo's original pape

The global dynamics of RNA stability orchestrates responses to cellular activation

Transcriptomics is used to quantify changes in accumulated levels of mRNAs following cellular activation. These changes arise from the opposing fluxes of transcription and mRNA decay, both of which affect the functional dynamics of global gene expression. A study published recently in BMC Genomics focuses on the contribution made by mRNA stability in shaping the kinetics of gene responses in mammalian cells

Study of intrinsic spin and orbital Hall effects in Pt based on a (6s, 6p, 5d) tight-binding model

We study the origin of the intrinsic spin Hall conductivity (SHC) and the d-orbital Hall conductivity (OHC) in Pt based on a multiorbital tight-binding model with spin-orbit interaction. We find that the SHC reaches 1000 \hbar/e\Omega cm when the resistivity \rho is smaller than ~10 \mu\Omega cm, whereas it decreases to 300 \hbar/e\Omega cm when \rho ~ 100 \mu\Omega cm. In addition, the OHC is still larger than the SHC. The origin of huge SHE and OHE in Pt is the large ``effective magnetic flux'' that is induced by the interorbital transition between d_{xy}- and d_{x2-y2}-orbitals with the aid of the strong spin-orbit interaction.Comment: 5 page

Development of a tight-binding potential for bcc-Zr. Application to the study of vibrational properties

We present a tight-binding potential based on the moment expansion of the density of states, which includes up to the fifth moment. The potential is fitted to bcc and hcp Zr and it is applied to the computation of vibrational properties of bcc-Zr. In particular, we compute the isothermal elastic constants in the temperature range 1200K < T < 2000K by means of standard Monte Carlo simulation techniques. The agreement with experimental results is satisfactory, especially in the case of the stability of the lattice with respect to the shear associated with C'. However, the temperature decrease of the Cauchy pressure is not reproduced. The T=0K phonon frequencies of bcc-Zr are also computed. The potential predicts several instabilities of the bcc structure, and a crossing of the longitudinal and transverse modes in the (001) direction. This is in agreement with recent ab initio calculations in Sc, Ti, Hf, and La.Comment: 14 pages, 6 tables, 4 figures, revtex; the kinetic term of the isothermal elastic constants has been corrected (Eq. (4.1), Table VI and Figure 4

On the origin of lowâ energy electrons in the inner magnetosphere: Fluxes and pitchâ angle distributions

Accurate knowledge of the plasma fluxes in the inner magnetosphere is essential for both scientific and programmatic applications. Knowledge of the lowâ energy electrons (approximately tens to hundreds of eV) in the inner magnetosphere is particularly important since these electrons are acted upon by various physical processes, accelerating the electrons to higher energies, and also causing their loss. However, measurements of lowâ energy electrons are challenging, and as a result, this population has been somewhat neglected previously. This study concerns observations of lowâ energy electrons made by the Helium Oxygen Proton Electron instrument on board the Van Allen Probes satellites and also observations from geosynchronous orbit made by the Magnetospheric Plasma Analyzer on board Los Alamos National Laboratory satellites. The fluxes of electrons from ~30â eV to 1â keV are quantified as a function of pitchâ angle, McIlwain L parameter, and local time for both quiet and active periods. Results indicate two sources for lowâ energy electrons in this energy range: the lowâ energy tail of the electron plasma sheet and the highâ energy tail of the dayside ionosphere. These populations are identified primarily as a result of their different pitchâ angle distributions. Fieldâ aligned outflows from the dayside ionosphere are observed at all L shells during quiet and active periods. Our results also demonstrate that the dayside electron fieldâ aligned fluxes at ~30â eV are particularly strong between L values of 6 and 7, indicating an enhanced source within the polar ionosphere.Key PointsLowâ energy electrons (tens to hundreds of eV) originate from two main sources: the ionosphere and the plasma sheetLowâ energy electrons pervade the inner magnetosphere where they can drive waveâ particle interactionsFluxes of electrons from ~30â eV to 1â keV are quantified by pitchâ angle, L value, and local time for both quiet and active periodsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136397/1/jgra53305_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136397/2/jgra53305.pd