Scientists at Tampere University and their international collaborators have made a groundbreaking discovery in the field of quantum physics. They have experimentally confirmed that angular momentum is conserved when a single photon is converted into a pair, validating a key principle of physics at the quantum level for the first time. This breakthrough has significant implications for creating complex quantum states useful in computing, communication, and sensing.

In essence, the researchers have tested the conservation laws of rotating objects to see if they also apply to light. They found that when a photon with zero orbital angular momentum is split into two photons, the OAM quanta of both photons must add to zero. This means that if one of the newly generated photons has one OAM quanta, its partner photon must have the opposite, i.e., negative OAM quanta.

The researchers used an extremely stable optical setup and delicate measurements to record enough successful conversions such that they could confirm the fundamental conservation law. They also observed first indications of quantum entanglement in the generated photon pairs, which suggests that the technique can be extended to create more complex photonic quantum states.

This work is not only of fundamental importance but also takes us a significant step closer to generating novel quantum states, where the photons are entangled in all possible ways. The researchers plan to improve the overall efficiency of their scheme and develop better strategies for measuring the generated quantum state such that in the future these photonic needles can be found easier in the laboratory haystack.

The confirmation of this fundamental quantum rule opens new possibilities for creating complex quantum states useful in computing, communication, and sensing. It also takes us a significant step closer to generating novel quantum states, where the photons are entangled in all possible ways, i.e., in space, time, and polarization.

The discovery of a new type of molecular carbon allotrope, known as cyclocarbon, has been a long-standing challenge for chemists. A team of researchers from Oxford University’s Department of Chemistry, led by Dr Yueze Gao and senior author Professor Harry Andersen, have successfully synthesized a stable 48-atom carbon ring in solution at room temperature. This achievement marks a significant breakthrough in the field, as previous attempts to study cyclocarbons were limited to the gas phase or extremely low temperatures (4 to 10 K).

The researchers employed a unique approach by synthesizing a cyclocarbon catenane, where the C48 ring is threaded through three other macrocycles. This design increases the stability of the molecule, preventing access to the sensitive cyclocarbon core. The team developed mild reaction conditions for the unmasking step in the synthesis process, which allowed them to achieve a stable cyclocarbon in solution at 20°C.

The cyclocarbon catenane was characterized using various spectroscopic techniques, including mass spectrometry, NMR, UV-visible, and Raman spectroscopy. The observation of a single intense 13C NMR resonance for all 48 sp1 carbon atoms provides strong evidence for the cyclocarbon catenane structure.

Lead author Dr Yueze Gao stated that achieving stable cyclocarbons in a vial at ambient conditions is a fundamental step, making it easier to study their reactivity and properties under normal laboratory conditions. Senior author Professor Harry Andersen added that this achievement marks the culmination of a long endeavor, with the original grant proposal written in 2016 based on preliminary results from 2012-2015.

The study also involved researchers from the University of Manchester, the University of Bristol, and the Central Laser Facility, Rutherford Appleton Laboratory. This collaborative effort demonstrates the power of interdisciplinary research in advancing our understanding of complex molecular systems.

This achievement has significant implications for future studies on cyclocarbons and their potential applications in various fields. The researchers’ innovative approach to synthesizing stable cyclocarbons at room temperature opens up new possibilities for exploring the properties and reactivity of these intriguing molecules.

Scientists have made a groundbreaking discovery in nuclear physics, measuring the heaviest nucleus ever recorded to decay via proton emission. This achievement marks the first time such a feat has been accomplished in over 30 years, with the previous record set in 1996.

The research team from the University of Jyväskylä, Finland, successfully produced and measured the lightest known isotope of astatine, 188At, consisting of 85 protons and 103 neutrons. This exotic nucleus was created through a complex process involving a fusion-evaporation reaction and identified using a sophisticated detector setup.

“The properties of this nucleus reveal a trend change in the binding energy of the valence proton,” explains Doctoral Researcher Henna Kokkonen, who led the study. “This could be explained by an interaction unprecedented in heavy nuclei.”

The research team’s findings have significant implications for our understanding of atomic nuclei and their behavior. By expanding a theoretical model to interpret the measured data, scientists can now better comprehend the intricate mechanisms governing these complex systems.

Kokkonen notes that studying such exotic nuclei is extremely challenging due to their short lifetimes and low production cross sections. However, precise techniques like those employed in this study have made it possible to unlock new insights into the fundamental nature of matter.

The research article was published in Nature Communications as part of an international collaboration involving experts in theoretical nuclear physics. This breakthrough discovery not only pushes the boundaries of human knowledge but also has far-reaching implications for our understanding of the universe and its mysteries.