3 research outputs found
Two-Particle Circular Billiards Versus Randomly Perturbed One-Particle Circular Billiards
We study a two-particle circular billiard containing two finite-size circular
particles that collide elastically with the billiard boundary and with each
other. Such a two-particle circular billiard provides a clean example of an
"intermittent" system. This billiard system behaves chaotically, but the time
scale on which chaos manifests can become arbitrarily long as the sizes of the
confined particles become smaller. The finite-time dynamics of this system
depends on the relative frequencies of (chaotic) particle-particle collisions
versus (integrable) particle-boundary collisions, and investigating these
dynamics is computationally intensive because of the long time scales involved.
To help improve understanding of such two-particle dynamics, we compare the
results of diagnostics used to measure chaotic dynamics for a two-particle
circular billiard with those computed for two types of one-particle circular
billiards in which a confined particle undergoes random perturbations.
Importantly, such one-particle approximations are much less computationally
demanding than the original two-particle system, and we expect them to yield
reasonable estimates of the extent of chaotic behavior in the two-particle
system when the sizes of confined particles are small. Our computations of
recurrence-rate coefficients, finite-time Lyapunov exponents, and
autocorrelation coefficients support this hypothesis and suggest that studying
randomly perturbed one-particle billiards has the potential to yield insights
into the aggregate properties of two-particle billiards, which are difficult to
investigate directly without enormous computation times (especially when the
sizes of the confined particles are small).Comment: 9 pages, 7 figures (some with multiple parts); published in Chao
Quantum clocks and their synchronisation - the Alternate Ticks Game
Time plays a crucial role in the intuitive understanding of the world around us. Within quantum mechanics, however, time is not usually treated as an observable quantity; it enters merely as a parameter in the laws of motion of physical systems. Here we take an operational approach to time. Towards this goal we consider quantum clocks, i.e., quantum systems that generate an observable time scale. We then study the quality of quantum clocks in terms of their ability to stay synchronised. To quantify this, we introduce the "Alternate Ticks Game" and analyse a few strategies pertinent to this game
Trace level voltammetric determination of Zn(II) in selected nutrition related samples by bismuth-oxychloride-multiwalled carbon nanotube composite based electrode
Bismuth-oxychloride-multiwalled carbon nanotube composite material was applied as surface modifier of glassy carbon electrode (BiOCl-MWCNT/GCE) for rapid and reliable trace level determination of Zn(II) in selected foodstuffs. The method development encompasses the optimization of electrode preparation including the transmission electron microscopic study of the modifier suspension, selection of the supporting electrolyte pH, the adjustment of the operation parameters of the SW-ASV measurements and the investigation of matrix effects. The BiOCl-MWCNT/GCE showed an excellent linear response towards Zn reoxidation peak maxima in the concentration range from 2.50 to 80.0 μg L−1 with the calculated LOD of 0.75 μg L−1 which was associated with 120 s accumulation time and accumulation potential −1.40 V vs SCE in acetate buffer pH 4.5. A satisfactory repeatability expressed as relative standard deviation of 4.8% was obtained in the case of 10.0 μg L−1 Zn(II) in model solution. The Zn(II) reoxidation signal from BiOCl-MWCNT/GCE received by the optimized SW-ASV method was compared with those recorded with bare, classical bismuth-film, multiwalled carbon nanotubes and by in situ made advanced bismuth-film-MWCNTs working electrodes. The applicability of the proposed BiOCl-MWCNT/GCE based method was corroborated via measuring the target analyte in two nutrition related real samples: in a dietary supplement and in a brewer's yeast sample. Comparative flame atomic absorption spectrometric measurements verified the obtained results in the case of yeast sample