Ground state of a partially melted Wigner molecule

We consider three spinless fermions free to move on 2d square lattice with periodic boundary conditions and interacting via a U/r Coulomb repulsion. When the Coulomb energy to kinetic energy ratio r_s is large, a rigid Wigner molecule is formed. As r_s decreases, we show that melting proceeds via an intermediate regime where a floppy two particle molecule coexists with a partially delocalized particle. A simple ansatz is given to describe the ground state of this mesoscopic solid-liquid regime.Comment: to appear in Europhysics Letter

Boundary hopping and the mobility edge in the Anderson model in three dimensions

It is shown, using high-precision numerical simulations, that the mobility edge of the 3d Anderson model depends on the boundary hopping term t in the infinite size limit. The critical exponent is independent of it. The renormalized localization length at the critical point is also found to depend on t but not on the distribution of on-site energies for box and Lorentzian distributions. Implications of results for the description of the transition in terms of a local order-parameter are discussed

Failure of single-parameter scaling of wave functions in Anderson localization

We show how to use properties of the vectors which are iterated in the transfer-matrix approach to Anderson localization, in order to generate the statistical distribution of electronic wavefunction amplitudes at arbitary distances from the origin of $L^{d-1} \times \infty$ disordered systems. For $d=1$ our approach is shown to reproduce exact diagonalization results available in the literature. In $d=2$, where strips of width $L \leq 64$ sites were used, attempted fits of gaussian (log-normal) forms to the wavefunction amplitude distributions result in effective localization lengths growing with distance, contrary to the prediction from single-parameter scaling theory. We also show that the distributions possess a negative skewness $S$, which is invariant under the usual histogram-collapse rescaling, and whose absolute value increases with distance. We find $0.15 \lesssim -S \lesssim 0.30$ for the range of parameters used in our study, .Comment: RevTeX 4, 6 pages, 4 eps figures. Phys. Rev. B (final version, to be published

Role of a parallel magnetic field in two dimensional disordered clusters containing a few correlated electrons

An ensemble of 2d disordered clusters with a few electrons is studied as a function of the Coulomb energy to kinetic energy ratio r_s. Between the Fermi system (small r_s) and the Wigner molecule (large r_s), an interaction induced delocalization of the ground state takes place which is suppressed when the spins are aligned by a parallel magnetic field. Our results confirm the existence of an intermediate regime where the Wigner antiferromagnetism defavors the Stoner ferromagnetism and where the enhancement of the Lande g factor observed in dilute electron systems is reproduced.Comment: 4 pages, 3 figure

Universal Spectral Correlation between Hamiltonians with Disorder

We study the correlation between the energy spectra of two disordered Hamiltonians of the form $H_a=H_{0a}+s_{a}\varphi$ ($a=1,2$) with $H_{0a}$ and $\varphi$ drawn from random distributions. We calculate this correlation function explicitly and show that it has a simple universal form for a broad class of random distributions.Comment: 9 pages, Jnl.tex Version 0.3 (version taken from the bulletin board), NSF-ITP-93-13

Post-international adoption medical follow-up at the Angers university hospital between 2009 and 2012.

OBJECTIVE: The authors had for aim to describe infectious diseases in internationally adopted child at arrival in France. PATIENTS AND METHODS: We made a retrospective descriptive study of the children\u27s files having undergone medical check-ups between 2009 and 2012. RESULTS: One hundred and eighty-two files were included: 80% of the children came from Africa, 15% from South America and the Caribbean, 3% from Asia, and 2% from Europe. Forty-three percent were diagnosed with tinea. HIV, hepatitis C, and syphilis blood tests were all negative. Six children presented with acute or chronic hepatitis B, another 5 children with acute hepatitis A. One blood test for cysticercosis was positive. Two children presented with malaria. 58% of the children carried an intestinal parasite; the most prevalent was Giardia duodenalis. Bacteriological stool culture was positive for 17 children, for 9 with an antibiotic resistant bacterium. Twenty-seven children had a positive virological stool culture, 2 for a poliovirus. CONCLUSION: A systematic infectious check-up should be performed for a child adopted internationally when he/she arrives in France. This allows diagnosing diseases requiring an emergency treatment, or asymptomatic but severe diseases when chronic. Some blood tests must be double-checked when the child arrives, because of possible false negative initial tests results in the country of origin. Screening, early treatment, and implementing prophylaxis can decrease the risk of transmission to relatives. It also allows monitoring the antimicrobial resistance of some pathogens and the reintroduction of the poliovirus in France

Strongly correlated wave functions for artificial atoms and molecules

A method for constructing semianalytical strongly correlated wave functions for single and molecular quantum dots is presented. It employs a two-step approach of symmetry breaking at the Hartree-Fock level and of subsequent restoration of total spin and angular momentum symmetries via Projection Techniques. Illustrative applications are presented for the case of a two-electron helium-like single quantum dot and a hydrogen-like quantum dot molecule.Comment: 9 pages. Revtex with 2 GIF and 1 EPS figures. Published version with extensive clarifications. A version of the manuscript with high quality figures incorporated in the text is available at http://calcite.physics.gatech.edu/~costas/qdhelproj.html For related papers, see http://www.prism.gatech.edu/~ph274c

Impact of serodiagnosis on the management of Lyme borreliosis at Angers University Hospital

Introduction Lyme borreliosis (LB) is an emerging arthropod-borne disease the diagnosis of which is made on clinical and biological data. We assessed the Angers University Hospital physicians’ management of LB, in case of positive serology, and estimated their compliance to European recommendations (EUCALB). Methods We retrospectively included 75 cases with positive ELISA serologies confirmed by Western-Blot, performed at the Angers University Hospital between 2008 and 2012. Results and discussion There were 4 cases of early localized phase, 26 of early-disseminated phase (including 17 cases of neuroborreliosis), and one case of late phase. The curative management complied with EUCALB guidelines in 28 cases out of 31. Conclusion Serology remains a reference diagnostic tool for LB, as long as the practitioner is aware of the main clinical and biological criteria

Random Matrix Theory of Scattering in Chaotic and Disordered Media

We review the random matrix theory describing elastic scattering through zero-dimensional ballistic cavities (having chaotic classical dynamics) and quasi-one dimensional disordered systems. In zero dimension, general symmetry considerations (flux conservation and time reversal symmetry) are only considered, while the combination law of scatterers put in series is taken into account in quasi-one dimension. Originally developed for calculating the distribution of the electrical conductance of mesoscopic systems, this theory naturally reveals the universal behaviors characterizing elastic scattering of various scalar waves.Comment: 17 pages, review articl

Character of eigenstates of the 3D disordered Anderson Hamiltonian

We study numerically the character of electron eigenstates of the three dimensional disordered Anderson model. Analysis of the statistics of inverse participation ratio as well as numerical evaluation of the electron-hole correlation function confirm that there are no localized states below the mobility edge, as well as no metallic state in the tail of the conductive band. We discuss also finite size effects observed in the analysis of all the discussed quantities.Comment: 7 pages, 9 figures, resubmitted to Physical Review