Related papers: $c$ at the belfry
The Bell-wave (B-wave) supposition has been introduced in an attempt to investigate Bell's conjecture (according to which "behind the scenes something is going faster than light"). Here it is shown, for the case of two entangled photons,…
We report a re-analysis of the old results from the Michelson-Morley interferometer experiments that were designed to detect absolute motion. We build upon a recent (1998) re-analysis of the original data by Munera, which revealed small but…
This problem was given on the Open Experimental Physics Olympiad (OEPO) "The day of the photon" on 25 April 2015. The Olympiad was a part of the celebration of the International Year of Light (IYL)…
Historically, the Michelson-Morley experiment has played a crucial role for abandoning the idea of a preferred reference frame, the ether, and for replacing Lorentzian Relativity with Einstein's Special Relativity. However, our re-analysis…
We present the main features of CITIUS, a new light source for ultrafast science, generating tunable, intense, femtosecond pulses in the spectral range from IR to XUV. The XUV pulses (about 10^5-10^8 photons/pulse in the range 14-80 eV) are…
The visualisation of objects moving at relativistic speeds has been a popular topic of study since Special Relativity's inception. While the standard exposition of the theory describes certain shape-changing effects, such as the…
A formulation of the one-way speed of light in three-dimensional Euclidean space is derived by a constructive approach. This formulation is consistent with the result of the Michelson-Morley experiment in that the harmonic mean of the…
The next 20 years will be the golden age of flavour physics, with the operation of the LHCb and Belle II experiments. After that an $e^+e^-$ collider could further improve the precision with sizeable $Z$, $W^+W^-$ and $t\bar{t}$ runs.
Gravitational lensing - the deflection of light rays by gravitating matter - has become a major tool in the armoury of the modern cosmologist. Proposed nearly a hundred years ago as a key feature of Einstein's theory of General Relativity,…
Time-of-flight (ToF) 3D imaging has a wealth of applications, from industrial inspection to movement tracking and gesture recognition. Depth information is recovered by measuring the round-trip flight time of laser pulses, which usually…
Since the pioneering works of Newton $(1643-1727)$, Mechanics has been constantly reinventing itself: reformulated in particular by Lagrange $(1736-1813)$ then Hamilton $(1805-1865)$, it now offers powerful conceptual and mathematical tools…
Ever since the first pulsar was discovered by Bell and Hewish over 40 years ago, we've known that not only are pulsars fascinating and truly exotic objects, but that we can use them as powerful tools for basic physics and astrophysics as…
By using the nonuniform discrete Fourier transform on the center positions of the symmetric intensity distribution of the output beam, we recover the vibration information of two mirrors, which is lost in the analysis of Danan \emph{et al.}…
The question of whether it is possible or not to surpass the speed of light is already centennial. The special theory of relativity took the existence of a speed limit as a principle, the light postulate, which has proven to be enormously…
In 1953 I heard of an experiment in 1925 by Bengt Str\"omgren where he observed transit times with the meridian circle at the Copenhagen University Observatory measuring the current in a photocell behind slits when a star was crossing. In…
We describe an undergraduate laboratory that combines an accurate measurement of the speed of light, a fundamental investigation of a basic laser system, and a nontrivial use of statistical analysis. Students grapple with the existence of…
The fine structure constant $\alpha $ includes the speed of light as given by $\alpha =\frac{e^{2}}{4\pi \epsilon_{0}c\hbar}$. It is shown here that, following a $TH\epsilon \mu $ formalism, interpreting the permittivity $\epsilon_{0}$ and…
Thermal diffusion has been studied for over 150 years. Despite of the long history and the increasing importance of the phenomenon, the physics of thermal diffusion remains poorly understood. In this paper Ludwig's thermal diffusion is…
Three experimental concepts investigating possible anisotropy of the speed of light are presented. They are based on i) beam deflection in a 180 degree magnetic arc, ii) narrow resonance production in an electron-positron collider, and iii)…
Though many experiments appear to have confirmed the light speed invariance postulate of special relativity theory, this postulate is actually unverified. This paper resolves this issue by first showing the manner in which an illusion of…