7,384 research outputs found
Particle diode: Rectification of interacting Brownian ratchets
Transport of Brownian particles interacting with each other via the Morse
potential is investigated in the presence of an ac driving force applied
locally at one end of the chain. By using numerical simulations, we find that
the system can behave as a particle diode for both overdamped and underdamped
cases. For low frequencies, the transport from the free end to the ac acting
end is prohibited, while the transport from the ac acting end to the free end
is permitted. However, the polarity of the particle diode will reverse for
medium frequencies. There exists an optimal value of the well depth of the
interaction potential at which the average velocity takes its maximum. The
average velocity decreases monotonically with the system size by
a power law .Comment: 7 pages, 9 figure
Ballistic Thermal Transistor of Dielectric Four-terminal Nanostructures
We report a theoretical model for a thermal transistor in dielectric
four-terminal nanostructures based on mesoscopic ballistic phonon transport, in
which a steady thermal flow condition of system is obtained to set up the
temperature field effect of gate. In the environment, thermal flow shows the
transisting behaviors at low temperatures: saturation, asymmetry, and
rectification. The phenomena can be explained reasonably by the nonlinear
variation of the temperature dependence of propagating phonon modes in
terminals. The results suggest the possibility of the novel nano-thermal
transistor fabrication
Market Stability Switches in a Continuous-Time Financial Market with Heterogeneous Beliefs
By considering a financial market of fundamentalists and trend followers in which the price trend of the trend followers is formed as a weighted average of historical prices, we establish a continuous-time financial market model with time delay and examines the impact of time delay on market price dynamics. Conditions for the stability of the fundamental price in terms of agents' behavior parameters and time delay are obtained. In particular, it is found that an increase in time delay can not only destabilize the market price but also stabilize an otherwise unstable market price, leading to stability switching as delay increases. This interesting phenomena shed new light in understanding of mechanism on the market stability. When the fundamental price becomes unstable through Hopf bifurcations, suffcient conditions on the stability and global existence of the periodic solution are obtained.asset price; fundamentalists; trend followers; delay differential equations; stability; bifurcations
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