4 research outputs found
Conductance distributions of 1D-disordered wires at finite temperature and bias voltage
We calculate the distribution of the conductance G in a one-dimensional
disordered wire at finite temperature T and bias voltage V in a
independent-electron picture and assuming full coherent transport. At high
enough temperature and bias voltage, where several resonances of the system
contribute to the conductance, the distribution P(G(T,V)) can be represented
with good accuracy by autoconvolutions of the distribution of the conductance
at zero temperature and zero bias voltage. The number of convolutions depends
on T and V. In the regime of very low T and V, where only one resonance is
relevant to G(T,V), the conductance distribution is analyzed by a resonant
tunneling conductance model. Strong effects of finite T and V on the
conductance distribution are observed and well described by our theoretical
analysis, as we verify by performing a number of numerical simulations of a
one-dimensional disordered wire at different temperatures, voltages, and
lengths of the wire. Analytical estimates for the first moments of P(G(T,V)) at
high temperature and bias voltage are also provided.Comment: 9 pages, 7 figures, Submitted to PR
Defining the effective temperature of a quantum driven system from current-current correlation functions
We calculate current-current correlation functions and find an expression for
the zero-frequency noise of multiterminal systems driven by harmonically
time-dependent voltages within the Keldysh non-equilibrium Green's functions
formalism. We also propose a fluctuation-dissipation relation for
current-current correlation functions to define an effective temperature. We
discuss the behavior of this temperature and compare it with the local
temperature determined by a thermometer and with the effective temperature
defined from a single-particle fluctuation-dissipation relation. We show that
for low frequencies all the definitions of the temperature coincide.Comment: 11 pages, 5 figure
Effect of host plant on the fitness of the spittlebug Notozulia entreriana: alternative method for rearing
Among the species belonging to 11 genera of Neotropical spittlebugs attacking graminaceous plants, Notozulia entreriana (Berg) (Hemiptera: Cercopidae) is one of the most important pests of grasses in several countries of South America. In this study, we evaluate the influence of three economically relevant species of host plants (Poaceae) on life-cycle traits of N. entreriana. We tested for differences in fitness responses (survival and fecundity) of insects on forage species which are frequent hosts for wild populations of spittlebugs. Comparison of life cycles on three host plants showed that only 2.5% of nymphs completed their development on Zea mays L., 22.5% on Chloris gayana Kunth, and 95% on Brachiaria decumbens Stapf. All the above suggests that C. gayana and B. decumbens are able to sustain complete development, behaving like natural hosts; the latter species is superior for artificial colonies because a shorter developmental period, higher survivorship in nymphs, and longer lifespan of adults were observed. Zea mays did not allow proper development, causing high mortality instead. We also developed a new approach for small-scale breeding of N. entreriana, which will enable subsequent biological and behavioral studies on this important pest species.Fil: Foieri, Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Virla, Eduardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Fundación Miguel Lillo; ArgentinaFil: Maciá, Arnaldo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; ArgentinaFil: Marino, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; Argentin