Noise-induced quantum transport

We analyze the problem of directed quantum transport induced by external exponentially correlated telegraphic noise. In addition to quantum nature of the heat bath, nonlinearity of the periodic system potential brings in quantum contribution. We observe that quantization, in general, enhances classical current at low temperature, while the differences become insignificant at higher temperature. Interplay of quantum diffusion and quantum correction to system potential is analyzed for various ranges of temperature, correlation time and strength of external noise and asymmetry parameters. A possible experimental realization of the observed quantum effects in a superionic conductor placed in a random asymmetric dichotomous electric field has been suggested.

Figure 1

Variation of current $\left(J\right)$ with quantum diffusion coefficient $D_q$ in the large correlation time limit for ${\Delta }_q=0.04$, $\theta =1.0$ and (i) $a=1.0$ and $b=2.0$ (solid line), (ii) $a=1.25$ and $b=2.25$ (dashed line), (iii) $a=1.5$ and $b=2.5$ (dot line), and (iv) $a=1.75$ and $b=2.75$ (dash-dot line).

Figure 2

Comparison of quantum and classical current $\left(J\right)$ vs temperature $\left(T\right)$ profile for the parameter set $a=1.75$, $b=2.75$, ${\Delta }_q=0.0$ (classical, dotted line) and ${\Delta }_q=0.3$ (quantum, solid line) in the large correlation time limit.

Figure 3

Variation of current $\left(J\right)$ with nonthermal noise strength $\left(Q_I\right)$ for different values of quantum diffusion coefficients $D_q=0.25$ (solid line), $D_q=1.5$ (dashed line), $D_q=3.0$ (dotted line), and $D_q=7.0$ (dash-dot line) for the parameter set ${\Delta }_q=0.04$, $\theta =1.0$, and $\tau =0.01$ in the short correlation time limit.

Figure 4

Comparison of quantum and classical current $\left(J\right)$ vs temperature $\left(T\right)$ profile for the parameter set $a=1.0$, $b=2.0$, $\tau =0.1$ and ${\Delta }_q=0.0$ (classical, dotted line) and ${\Delta }_q=0.3$ (quantum, solid line) in the short correlation time limit.

Figure 5

Variation of current $\left(J\right)$ with quantum diffusion coefficient for different value of correlation time $\tau$ of nonthermal noise $\tau =0.05$ (solid line), $\tau =0.07$ (dashed line) and $\tau =0.1$ (dotted line) for the parameter set ${\Delta }_q=0.04$, $a=1.0$, $b=2.0$ and $\theta =1.0$ in the short correlation time limit.