An experiment confirms that something travels faster than light. The prediction that this could happen was formulated in the 1970s. However, until now, it had not been possible to prove it.
One published last week in the magazine Nature once again focused attention on one of the best-known limits of physics: the speed of light.
A team from the Technion-Israel Institute of Technology measured, for the first time, dark spots within a light wave that, according to experience, move faster than light itself.
The idea may sound like a direct challenge to theories of Albert Einsteinbut the discovery does not mean that your theory has been invalidated.
What the researchers observed were not particles with mass or signals capable of transporting energy or information, but rather light vorticesalso described as null pointsor areas where the wave amplitude drops to zero. I.e, regions of darkness embedded in the luminous field itself.
This detail is decisive to understand why the result attracted so much attention, says . The prediction existed since the 1970s, when several studies raised the hypothesis that these vortices could move at a speed greater than that of the wave that contains them.
In the new study, the Israeli team guarantees to have it experimentally confirmed thanks to an electron microscope capable of recording extremely fast and minute phenomena with unprecedented resolution.
Far from speaking of a material object surpassing light in the void, the study describes an internal behavior of waves. The so-called dark spots function as small “voids” in the wave structurea type of whirlpool that also appears in other natural systems, such as water or air.
The uniqueness, in this case, lies in the fact that this whirlpool, within a wave, can advance faster than the general pattern in which it is formed. The authors managed to observe it in material identified as hBNprepared by the teacher Hanan Herzig Sheinfuxda Bar-Ilan University.
In this environment, light waves transform into hybrid waves of light and soundknown as in polaritywhich move unusually slowly, at a speed about 100 times slower than that of light in a vacuum. It was precisely this slowdown that made it possible to detect how the vortices were able to make a kinematic leap and exceed this local threshold.
To record this movement, scientists integrated a laser system and an advanced optomechanical setup into a specialized electron microscope at the Technion’s Electron Microscopy Center.
This combination made it possible directly measure an ultra-fast dance which, until now, remained at the theoretical level. The work, therefore, does not rewrite relativity, but it forces us to better specify the way in which certain wave structures behave in extreme conditions.
The scope of the result will beyond mere physical curiosity. “Our discovery reveals universal laws of nature shared by all types of wavesfrom sound waves and fluid flows to complex systems such as superconductors”, explains Ido Kaminermain author of the study, at .
“We believe that these innovative microscopy techniques will make it possible to study hidden processes in physics, chemistry and biology, revealing for the first time how nature behaves in its fastest moments and more difficult to capture”, he adds.
In addition to the historical value of experimentally proving a prediction formulated decades ago, the investigation opens up new avenues for microscopyfor nanostructure-based optics, for the study of superconductivity and for methods of encoding quantum information in materials.
More than demonstrating that Einstein was wrong, something that scientists are trying to do, the experience shows that, even within a well-established physical principle, there continue to be phenomena capable of challengingsurprising and expanding the limits of what was thought to be understood.
