1,720,990 research outputs found
Unruh temperature with maximal acceleration
No full textIn this paper, we modify the geometry of Rindler space so as to include an upper limit on the acceleration. Caianiello and his collaborators, in a series of papers, have analyzed the corrections to the classical spacetime metrics due to the existence of a maximal acceleration. Our goal is to derive, in this context, in a very simple way, the so-called Unruh temperature
Heuristically Sifting Twins
No full textThis article has a pedagogical aim. Indeed, we want to tackle the twin primes conjecture with an elementary and intuitive approach suitable for high schools. Perhaps it is needless to point out that this article does not have such a high goal of proving the conjecture but to give an intuitive idea of its validity. Research on prime numbers and related conjectures is so vast and advanced that it is impossible to fully address it in a high school. Hence, we want to analyze the twin primes from a didactic point of view and with the knowledge of high schools. Even a simple approach seems to indicate that there are infinitely many twin primes
Keplerian motion on a carousel: a research teaching project
No full textItalian ministerial programs have introduced the teaching of modern physics in the last year of high school (students of 18 years). The textbooks also introduce, obviously in an elementary way, some current problems as, for example, the mysterious galactic rotation curves. It is explained that the cause of their non-Keplerian motion is due to the presence of a non-luminous form of matter and, for this reason, called Dark Matter. To stimulate the curiosity of students who have an aptitude for research, it might be useful to observe that "dark particles" are not provided by the standard model of particle physics and most cosmologists believe in their existence only because they very well explain a series of experimental observations. For this reason, in our opinion, it is interesting to highlight that, until a dark particle is found, it is not wrong to look for an alternative explanation of the experimental data. For example, to simulate the strange behavior of galaxies rotation using elementary and well-known concepts, we have built with students, during a series of lectures in the classroom, a Galilean composition between a Keplerian motion and a very slow circular motion
Hafele and Keating in a fictious gravitational field
No full textThe so called twin paradox is described in every special relativity (SR) textbook. Obviously, an exact calculation requires the application of the general theory of relativity (GR) but, thanks to some simplifying hypotheses concerning the acceleration and deceleration phases, even in SR it is possible to find the correct solution and that is "the twin who goes on space travel is the one who, returning to Earth, finds the aged brother." In a curved spacetime, instead, we have the algebraic sum between a kinematic and a gravitational effect. What happens in the presence of a gravitational field is, for example, well described by Hafele and Keating's experiment and, in this case, it may happen that the traveling brother can grow older than his brother at rest. Continuing in this pedagogical tradition, we consider the Hafele and Keating experiment in a fictious gravitational field of a rotating frame. The equality of the results between curved spacetime of a real gravitational field and flat spacetime of a fictitious one, in our opinion, is interesting to emphasize even today the great genius of Einstein and that is "inertia is gravity in disguise"
Twin paradox in curved spacetime
No full textThe twin paradox has played an important role in the history of special relativity (SR). A precise calculation would require the application of the general theory of relativity (GR) but, neglecting the acceleration phases of the traveling twin, even in SR it is possible to find the correct solution without logical contradictions. Nowadays it is well known that the twin thought experiment seems a paradox as a consequence of a naive application of time dilation and the principle of relativity. The twin who goes on space travel is the one who, returning to the twin at rest, finds the aged brother. Continuing in this pedagogical tradition, we want to add a further consideration. In fact, the experiment has always been explained by considering the two twins immersed in Minkowski’s spacetime. It could be interesting, from a didactic point of view, to analyze the same thought experiment without neglecting the Earth’s gravitational field. Indeed, under certain conditions, it may happen that the traveling brother can grow older than his brother at res
On the velocity of a quantum particle in the de Broglie–Bohm quantum mechanics: the case of the bouncing ball
Full text linkStarting from the dynamics of a bouncing ball in classical and quantum regime, we suggest a modification of the probability current in quantum mechanics. We consider the consequences of this generalization on the resulting velocity of a quantum particle in the de Broglie–Bohm interpretation of quantum mechanics
Playing with two rays of light
No full textThe special theory of relativity is currently included in the curricula of high school in many countries. For this reason, we often organize in-depth lessons on this topic and, in this paper, we summarize a lecture that we have given in some extra activities addressed to last year high school students stimulating pupils “to play” with Lorentz transformations. We found a simple relation that allows us to deduce the rest length of a relativistic train without knowing the relative velocity and without using the lorentz factor and spacetime distortions
Relativistic mean proportion
Full text linkThe so called modern physics is at present included in the curricula of high school. Therefore, we often organize in-depth lessons on quantum mechanics and on the special theory of relativity (SR). In the following sections, we want to show a lesson given by the first author of this paper. He proposes to students a proportion to deduce relativistic time dilation and length contraction without knowing the Lorentz transformations
Distance measures in cosmology: a simple approach
Full text linkThe aim of this paper is to analyze the concept of cosmological distance with a simple didactic approach that is not easy to find in textbooks. In this way, we hope to help facilitate student learning about this issue.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
- …
