Showing papers by "Pierre Le Doussal published in 1993"

Flux pinning and forced vortex entanglement by splayed columnar defects.

Abstract: We propose controlled splay of artificial columnar defects in cuprate superconductors as a strategy to enhance transport properties in a field compared to parallel columns. The theory predicts a new splayed glass'' phase characterized by a reduced flux creep, an entangled ground state, and an astronomically slow response to an applied transverse field.

Flat glassy phases and wrinkling of polymerized membranes with long-range disorder.

Abstract: We study polymerized membranes with long-range quenched internal disorder in the preferred metric and/or the extrinsic curvature characterized by disorder range exponents z μ , z k , respectively. We find several new flat glassy phases stable at T>0 in different regions of the z μ ,z k plane. We calculate the z-dependent roughness exponents and amplitudes that characterize these new phases. When z μ ,z k exceed critical values z μ , z k (characteristic of each phase), these glassy flat phases undergo a transition towards a crumpled phase, similar to the crumpled glass previously predicted

Rotational invariance and the theory of directed nematic polymers.

Abstract: The consequences of rotational invariance in a recent theory of fluctuations in dilute polymer nematics are explored. A correct rotationally invariant free energy insures that anomalous couplings are not generated in a one-loop renormalization group calculation.