Pasquale Onorato

Teaching quantum physics by the sum over paths approach and GeoGebra simulations

We present a research-based teaching sequence in introductory quantum physics using the Feynman sum over paths approach. Our reconstruction avoids the historical pathway, and starts by reconsidering optics from the standpoint of the quantum nature of light, analysing both traditional and modern experiments. The core of our educational path lies in the treatment of conceptual and epistemological themes, peculiar of quantum theory, based on evidence from quantum optics, such as the single photon Mach–Zehnder and Zhou–Wang–Mandel experiments. The sequence is supported by a collection of interactive simulations, realized in the open source GeoGebra environment, which we used to assist students in learning the basics of the method, and help them explore the proposed experimental situations as modeled in the sum over paths perspective. We tested our approach in the context of a post-graduate training course for pre-service physics teachers; according to the data we collected, student teachers displayed a greatly improved understanding of conceptual issues, and acquired significant abilities in using the sum over path method for problem solving.

Quantitative analysis of transmittance and photoluminescence using a low cost apparatus

We show how a low cost spectrometer, based on the use of inexpensive diffraction transmission gratings coupled with a commercial digital photo camera or a cellphone, can be assembled and employed to obtain quantitative spectra of different sources. In particular, we discuss its use in studying the spectra of fluorescent colored ink, used in highlighting pens, for which the transmission band and the emission peaks are measured and related to the ink color.

What Feynman Could Not yet Use: The Generalised Hong-Ou-Mandel Experiment to Improve the QED Explanation of the Pauli Exclusion Principle.

In this paper we present a reasoning line for introducing the Pauli exclusion principle in the context of an introductory course on quantum theory based on the sum over paths approach. We start from the argument originally introduced by Feynman in QED: The Strange Theory of Light and Matter and improve it by discussing with students modern experimental evidence from the famous Hong–Ou–Mandel experiment with indistinguishable photons and its generalised version using electrons. The experiments can be analysed in a rather simple way using Feynmans method of arrow multiplication for treating processes involving more than one quantum object. The approach described is especially relevant in the formation of high school physics teachers to the basics of modern physics.

Improving the connection between the microscopic and macroscopic approaches to thermodynamics in high school

In this article we discuss a teaching learning sequence on basic thermodynamics, spanning the first and second principle, and the concepts of irreversibility and entropy, intended for use in secondary school. With respect to previous works we emphasise the importance of discussing the compatibility between the time reversal symmetry of Newtons laws and the irreversibility embodied in the second principle of thermodynamics in order to completely exploit the possibility of connecting the microscopic and macroscopic perspectives. The sequence was tested in an Italian secondary school, and the results obtained from a questionnaire which combines several test items used in previous studies at university level are consistently comparable with or better than those reported for undergraduate students on the same questions over a range of topics. Thus, our work suggests that the microscopic approach is a viable option for the teaching of thermodynamics at the secondary school level; and the understanding of macroscopic concepts is not impaired, but possibly enhanced, by the adoption of such a teaching strategy.

Two experiments for the measurement of the centre of percussion of a physical pendulum

In this article we describe two experiments, performed with instrumentation commonly available in undergraduate laboratories, to measure the position of the centre of percussion of a physical pendulum. The first one makes use of a constant external force provided by a common spring dynamometer, and allows for a straightforward analysis founded on basic concepts of rigid body dynamics. The second one is, more properly, an experiment based on a percussion, i.e. a collision involving an almost impulsive force, and displays the typical difficulties, but also the physical richness, of this type of phenomena. We provide an historical overview of the problem of the centre of percussion, starting from its first formulation given by Bernardino Baldi at the end of the 16th century, and we show how the mathematical model built for analysing the impact between a physical pendulum and a localised object is helpful in understanding that such a problem, in its original formulation, does not have a unique answer.