Households with high incomes are the main beneficiaries of subsidy programmes supporting the clean energy transition. A team of researchers from the University of Freiburg, Stanford University, Indiana University and the University of Pennsylvania has analysed why this is the case and how energy policy can be made more equitable. The results have now been published in the journal Nature Reviews Clean Technology.

Researchers from the Technion–Israel Institute of Technology have achieved the first direct measurement of “dark points” within light waves, experimentally confirming a theoretical prediction from the 1970s that these features can move faster than the speed of light. The study, published in Nature, was led by Prof. Ido Kaminer and an international team of collaborators.

The “dark points,” also known as optical vortices, are locations within a light wave where the intensity drops to zero. While it may seem to challenge Einstein’s theory of relativity, these points do not carry mass, energy, or information, and therefore do not violate the universal speed limit.

Using a uniquely developed ultrafast electron microscopy system, the team achieved record spatial and temporal resolution, enabling them to track these elusive features. The experiments were conducted in a material (hexagonal boron nitride, hBN) that supports polaritons—hybrid light-sound waves that move significantly slower than light—allowing the vortices to effectively outpace the wave itself.

Beyond confirming a long-standing theoretical prediction, the findings reveal universal wave behaviors applicable across physics, from fluid dynamics to superconductivity. The work also introduces advanced electron interferometry techniques that could transform nanoscale imaging and enable new insights into ultrafast processes in physics, chemistry, and biology.

This breakthrough opens new avenues for research in microscopy, nanophotonics, superconductivity, and quantum information science.