Random matrix study for a three-terminal chaotic device

We perform a study based on a random-matrix theory simulation for a three-terminal device, consisting of chaotic cavities on each terminal. We analyze the voltage drop along one wire with two chaotic mesoscopic cavities, connected by a perfect conductor, or waveguide, with one open mode. This is done by means of a probe, which also consists of a chaotic cavity that measure the voltage in different configurations. Our results show significant differences with respect to the disordered case, previously considered in the literature.Comment: Proccedings of the V Leopoldo Garcia-Colin Mexican Meeting on Mathematical and Experimental Physic

Typical length scales in conducting disorderless networks

We take advantage of a recently established equivalence, between the intermittent dynamics of a deterministic nonlinear map and the scattering matrix properties of a disorderless double Cayley tree lattice of connectivity $K$, to obtain general electronic transport expressions and expand our knowledge of the scattering properties at the mobility edge. From this we provide a physical interpretation of the generalized localization length.Comment: 12 pages, 3 figure

Absorption and Direct Processes in Chaotic Wave Scattering

Recent results on the scattering of waves by chaotic systems with losses and direct processes are discussed. We start by showing the results without direct processes nor absorption. We then discuss systems with direct processes and lossy systems separately. Finally the discussion of systems with both direct processes and loses is given. We will see how the regimes of strong and weak absorption are modified by the presence of the direct processes.Comment: 8 pages, 4 figures, Condensed Matter Physics (IV Mexican Meeting on Mathematical and Experimental Physics), Edited by M. Martinez-Mares and J. A. Moreno-Raz

Metallic properties of magnesium point contacts

We present an experimental and theoretical study of the conductance and stability of Mg atomic-sized contacts. Using Mechanically Controllable Break Junctions (MCBJ), we have observed that the room temperature conductance histograms exhibit a series of peaks, which suggests the existence of a shell effect. Its periodicity, however, cannot be simply explained in terms of either an atomic or electronic shell effect. We have also found that at room temperature, contacts of the diameter of a single atom are absent. A possible interpretation could be the occurrence of a metal-to-insulator transition as the contact radius is reduced, in analogy with what it is known in the context of Mg clusters. However, our first principle calculations show that while an infinite linear chain can be insulating, Mg wires with larger atomic coordinations, as in realistic atomic contacts, are alwaysmetallic. Finally, at liquid helium temperature our measurements show that the conductance histogram is dominated by a pronounced peak at the quantum of conductance. This is in good agreement with our calculations based on a tight-binding model that indicate that the conductance of a Mg one-atom contact is dominated by a single fully open conduction channel.Comment: 14 pages, 5 figure

Squeeze-film levitation characteristics of plates excited by piezoelectric actuators

A small mass is levitated by a vibrating plate with an arrangement of four piezoelectric actuators that generate a squeeze-film in the gap between the plate and the mass. Different arrangements of actuators and plate design are explored using simulation in order to produce better performance