arXiv subjects
Publications and source records attributed to Thierry Giamarchi.
We examine the effects of disorder in one-dimensional systems. We link the case of a few impurities, typical of a short quantum wire, to that of a finite density of scatterers more appropriate for a long wire or a macroscopic system. Finally we investigate the effects of long-range interactions on the transport in 1D systems. We predict in that case a conductivity behaving as $σ(T) \sim T^2$.}
We study periodic lattices, such as vortex lattices, driven by an external force in a random pinning potential. We show that effects of static disorder persist even at large velocity. It results in a novel moving glass state with topological order analogous to the static Bragg glass. The lattice flows through well-defined, elastically coupled, {\it % static} channels. We predict barriers to transverse motion resulting in finite transverse critical current. Experimental tests of the theory are proposed.
We apply the gaussian variational method (GVM) to study the equilibrium statistical mechanics of the two related systems: (i) classical elastic manifolds, such as flux lattices, in presence of columnar disorder correlated along the $τ$ direction (ii) interacting quantum particles in a static random potential. We find localization by disorder, the localized phase being described by a replica symmetry broken solution confined to the mode $ω=0$. For classical systems we compute the correlation function of relative displacements. In $d=2+1$, in the absence of dislocations, the GVM allows to describes the Bose glass phase. Along the columns the displacements saturate at a length $l_{\perp}$ indicating flux-line localization. Perpendicularly to the columns long range order is destroyed. We find divergent tilt modulus $c_{44}=\infty$ and a $x \sim τ^{1/2}$ scaling. Quantum systems are studied using the analytic continuation from imaginary to real time $τ\to i t$. We compute the conductivity and find that it behaves at small frequency as $σ(ω) \approx ω^2$ in all dimensions ($d < 4$) for which disorder is relevant. We compute the quantum localization length $ξ$. In $d=1$, where the model also describes interacting fermions in a static random potential, we find a delocalization transition and obtain analytically both the low and high frequency behavior of the conductivity for any value of the interaction. We show that the marginality condition appears as the condition to obtain the correct physical behavior. Agreement with renormalization group results is found whenever it can be compared.