Luttinger States at the Edge

An effective wavefunction for the edge excitations in the Fractional quantum Hall effect can be found by dimensionally reducing the bulk wavefunction. Treated this way the Laughlin $\nu=1/(2n+1)$ wavefunction yields a Luttinger model ground state. We identify the edge-electron field with a Luttinger hyper-fermion operator, and the edge electron itself with a non-backscattering Bogoliubov quasi-particle. The edge-electron propagator may be calculated directly from the effective wavefunction using the properties of a one-dimensional one-component plasma, provided a prescription is adopted which is sensitive to the extra flux attached to the electrons

Scaling and interaction-assisted transport in graphene with one-dimensional defects

We analyze the scattering from one-dimensional defects in intrinsic graphene. The Coulomb repulsion between electrons is found to be able to induce singularities of such scattering at zero temperature as in one-dimensional conductors. In striking contrast to electrons in one space dimension, however, repulsive interactions here can enhance transport. We present explicit calculations for the scattering from vector potentials that appear when strips of the material are under strain. There the predicted effects are exponentially large for strong scatterers.Comment: 4 pages, 2 figure

Quantum critical phenomena of long-range interacting bosons in a time-dependent random potential

We study the superfluid-insulator transition of a particle-hole symmetric system of long-range interacting bosons in a time-dependent random potential in two dimensions, using the momentum-shell renormalization-group method. We find a new stable fixed point with non-zero values of the parameters representing the short- and long-range interactions and disorder when the interaction is asymptotically logarithmic. This is contrasted to the non-random case with a logarithmic interaction, where the transition is argued to be first-order, and to the $1/r$ Coulomb interaction case, where either a first-order transition or an XY-like transition is possible depending on the parameters. We propose that our model may be relevant in studying the vortex liquid-vortex glass transition of interacting vortex lines in point-disordered type-II superconductors.Comment: 10 pages, 3 figure

Fatalism and Future Contingents

In this paper I address issues related to the problem of future contingents and the metaphysical doctrine of fatalism. Two classical responses to the problem of future contingents are the third truth value view and the all-false view. According to the former, future contingents take a third truth value which goes beyond truth and falsity. According to the latter, they are all false. I here illustrate and discuss two ways to respectively argue for those two views. Both ways are similar in spirit and intimately connected with fatalism, in the sense that they engage with the doctrine of fatalism and accept a large part of a standard fatalistic machinery

Solvation force for long ranged wall-fluid potentials

The solvation force of a simple fluid confined between identical planar walls is studied in two model systems with short ranged fluid-fluid interactions and long ranged wall-fluid potentials decaying as $-Az^{-p}, z\to \infty$, for various values of $p$. Results for the Ising spins system are obtained in two dimensions at vanishing bulk magnetic field $h=0$ by means of the density-matrix renormalization-group method; results for the truncated Lennard-Jones (LJ) fluid are obtained within the nonlocal density functional theory. At low temperatures the solvation force $f_{solv}$ for the Ising film is repulsive and decays for large wall separations $L$ in the same fashion as the boundary field $f_{solv}\sim L^{-p}$, whereas for temperatures larger than the bulk critical temperature $f_{solv}$ is attractive and the asymptotic decay is $f_{solv}\sim L^{-(p+1)}$. For the LJ fluid system $f_{solv}$ is always repulsive away from the critical region and decays for large $L$ with the the same power law as the wall-fluid potential. We discuss the influence of the critical Casimir effect and of capillary condensation on the behaviour of the solvation force.Comment: 48 pages, 12 figure

The tunneling conductance between a superconducting STM tip and an out-of-equilibrium carbon nanotube

We calculate the current and differential conductance for the junction between a superconducting (SC) STM tip and a Luttinger liquid (LL). For an infinite single-channel LL, the SC coherence peaks are preserved in the tunneling conductance for interactions weaker than a critical value, while for strong interactions (g <0.38), they disappear and are replaced by cusp-like features. For a finite-size wire in contact with non-interacting leads, we find however that the peaks are restored even for extremely strong interactions. In the presence of a source-drain voltage the peaks/cusps split, and the split is equal to the voltage. At zero temperature, even very strong interactions do not smear the two peaks into a broader one; this implies that the recent experiments of Y.-F. Chen et. al. (Phys. Rev. Lett. 102, 036804 (2009)) do not rule out the existence of strong interactions in carbon nanotubes.Comment: 8 pages, 3 figure

Interacting topological phases in multiband nanowires

We show that semiconductor nanowires coupled to an s-wave superconductor provide a playground to study effects of interactions between different topological superconducting phases supporting Majorana zero-energy modes. We consider quasi-one dimensional system where the topological phases emerge from different transverse subbands in the nanowire. In a certain parameter space, we show that there is a multicritical point in the phase diagram where the low-energy theory is equivalent to the one describing two coupled Majorana chains. We study effect of interactions as well as symmetry-breaking perturbations on the topological phase diagram in the vicinity of this multicritical point. Our results shed light on the stability of the topological phase around the multicritical point and have important implications for the experiments on Majorana nanowires.Comment: 8 pages, 2 figures; final version to appear in PR

Absence of a Phase Transition in a Three--Dimensional Vortex Glass Model with Screening

We study the gauge glass model for the vortex glass transition in type--II superconductors, including screening of the interaction between vortices. {}From the size dependence of the domain wall energy we find that, in two--dimensions, the transition is at $T=0$ both with and without screening but the exponents are different in the two cases. In three-dimensions, we find that screening destroys the finite temperature transition found earlier when screening was neglected.Comment: 11 pages plus LaTeX with Revtex macros, 3 postscript figures, uuencoded and compressse

Signatures of spin-charge separation in scanning probe microscopy

We analyze the effect of an auxiliary scatterer, such as the potential of a scanning tip, on the conductance of an interacting one-dimensional electron system. We find that the differential conductance for tunneling into the end of a semi-infinite quantum wire reflects the separation of the elementary excitations into spin and charge modes. The separation is revealed as a specific pattern in the dependence of the conductance on bias and on the position of the scatterer.Comment: 4 pages, 1 figure; published versio

Quantum Resistive Transition in Type II Superconductors under Magnetic Field

It is shown that, within a Ginzburg-Landau (GL) formalism, the superconducting fluctuation is insulating at zero temperature even if the fluctuation dynamics is metallic (dissipative). Based on this fact, the low temperature behavior of the $H_{c2}$-line and the resistivity curves near a zero temperature transition are discussed. In particular, it is pointed out that the neglect of quantum fluctuations in data analysis of the dc resistivity may lead to an under-estimation of the $H_{c2}$ values near zero temperature.Comment: 7 page