Random telegraph signal

Efros, A. L. and Rosen, M. (1997) Random telegraph signal in the photoluminescence intensity of a single quantum dot Phys. Rev. Lett, 78, 1110-1113. 

The results for i p(r) obtained for different values of A, see Fig. 1.11, demonstrate that under a random telegraph signal the coherence of noise-induced excitation is enhanced by an optimal choice of the correlation time. Here, the optimal correlation time Topt decreases as the noise amplitude A increases. Further simulations not shown here, confirm that this phenomenon holds for a wide range of the bifurcation parameter o, covering almost the whole excitable regime. We emphasize that for not well separated time scales, noise-induced excitations are possible even if both cp-... 

Fig. 1.10. Coliei ence resonance with respect to the correlation time in the light-sensitive BZ reaction. Tlie normalized fluctuations of the inter-spike times are reported versus tlie correlation time of the random telegraph signal. [7]...

Figure 11. The auto-correlation function of the fluorescence intensity reveals the characteristic times of the random telegraph signal in Fig. 10. Here, three examples of correlation functions of different terrylene molecules in polyethylene at 1.8 K illustrate (note the logarithmic time axis) (a) an exponential decay (with fit, smooth line) (b) a bi-exponential decay and (c) a decay with many timescales. Such different behaviours may reflect molecules coupled strongly to one, two or many tunneling systems.

To extend the validity range of noise-induced phenomena for a wider range of correlation times the dichotomous Markov noise has been used. The dichotomus Markov noise, also known as the random telegraph signal has a quite simple structure, therefore the stationary probability density can be calculated for an arbitrary value of the correlation time, and for any value of the noise intensity. The state of the Markovian dichotomous noise /, consists of two levels A+, A only. The noise is characterised by the transition probability ... 

M. Fujii, T. Kita, S. Hayashi, K. Yamamoto Current-transport properties of Ag-Si02 and Au-Si02 composite films Observation of single-electron tunnelling and random telegraph signals, J. Phys. Condens. Matter 9, 8669-8677 (1997)... 

Let us now consider the case ii)b), i.e. the two-state noise case. This noise is also known as the random telegraph signal. It is characterized by the following, so-called. Master equation... 

FIGURE 6.5 Contact fluctuations in molecular junctions (a) An STM probe was scanned over an octane-thiol monolayer containing inserted octanedithiol molecules (red dot at each end), (b) The top thiol contact appears as a bright spot in the STM image (i) but will spontaneously disappear (ii) only to reappear in a later scan at the same point (iii). (c) The same phenomenon can be seen when the probe is stopped over octanedithiol molecules. The contact turns on and off on a timescale of tens of milliseconds to produce random telegraph signals in the current as shown in panel (d). 

We will revisit measurements of this type when we discuss RT. But first, we turn to measurements of molecular dynamics based on random telegraph signals generated as molecules interact with CNTs. 

Figure 10. Illustration of how changes of state of a tunneling system in the neighbourhood of a molecule cause a random telegraph fluorescence signal by shilling the molecule in and out of resonance with the fixed laser frequency.

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