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Researchers at the Department of Instrumentation and Applied Physics (IAP), Indian Institute of Science (IISc) and collaborators have designed a new supercapacitor that can be charged by light shining on it. Such supercapacitors can be used in various devices, including streetlights and self-powered electronic devices such as sensors.

Capacitors are electrostatic devices that store energy as charges on two metal plates called electrodes. Supercapacitors are upgraded versions of capacitors—they exploit electrochemical phenomena to store more energy, explains Abha Misra, Professor at IAP and corresponding author of the study published in the Journal of Materials Chemistry A.

The electrodes of the new supercapacitor were made of zinc oxide (ZnO) nanorods grown directly on fluorine-doped tin oxide (FTO), which is transparent. It was synthesized by Pankaj Singh Chauhan, first author and CV Raman postdoctoral fellow in Misra’s group at IISc.

In the case of NiPS₃, the researchers observed an intermediate symmetry breaking which leads to a vestigial order. Just as the term “vestigial” refers to the retention of certain traits during the process of evolution, the vestigial order here can also be viewed as the retention during the process of symmetry breaking.

This happens when the primary magnetic long-range order state melts or breaks down into a simpler form, in the NiPS₃ case, a 2D vestigial order state (known as Z₃ Potts-nematicity), as the material is thinned. Unlike conventional symmetry breaking, which involves the breaking of all symmetries, vestigial order only involves the breaking of some symmetries.

While there are numerous examples from a theoretical standpoint, experimental realizations of vestigial order have remained challenging. However, the investigation of this 2D magnetic material has shed the first light on this issue, demonstrating that such a phenomenon can be observed through dimension crossover.

A better understanding of the inner workings of neutron stars will lead to a greater knowledge of the dynamics that underpin the workings of the universe and also could help drive future technology, said the University of Illinois Urbana-Champaign physics professor Nicolas Yunes. A new study led by Yunes details how new insights into how dissipative tidal forces within double—or binary—neutron star systems will inform our understanding of the universe.

A collaborative study by the University of Cologne revealed that magnetic excitations in BaCO2V2O8 crystals involve unusual repulsively bound states, a significant discovery made by irradiating the crystals with terahertz waves.

A team of solid-state physicists from the University of Cologne, along with international collaborators, studied BaCO2V2O8 crystals in a laboratory in Cologne. Their research revealed that the magnetic elementary excitations in the crystals are influenced by both attractive and repulsive interactions.

However, this results in a lower stability, making the observation of such repulsively bound states all the more surprising. The results of the study were recently published in Nature.

You know the classic game Pong with the paddles and ball that moves across the screen? Imagine the ball and paddles synchronized to music. Victor Tao approached the challenge as an optimization problem to figure out where the paddle and balls should go, based on the beats of a song:

Fortunately there is a mature field dedicated to optimizing an objective (screen utilization) with respect to variables (the locations of bounces) in the presence of constraints on those variables (physics and the beats of the song). If we write our requirements as a constrained optimization problem, we can use an off-the-shelf solver to compute optimal paddle positions instead of designing an algorithm ourselves.

Continue reading “Music visualizer in the style of a Pong game” »

The world keeps time with the ticks of atomic clocks, but a new type of clock under development—a nuclear clock—could revolutionize how we measure time and probe fundamental physics.

How much do we really know about what else is out there in the universe?

You can demonstrate a subjective quality like redness is different from red light. If you add a device that converts a red signal into a green one, between the retina and the optic nerve, the strawberry will seem green. It’s not about light hitting the retina, it’s about how the signal is processed. In this case, the greenness must be a quality of our conscious knowledge of the strawberry, not of the red light landing on the retina. If you use sufficient, well defined terminology, you can objectively communicate the nature of subjective qualities. For example, even though you know what it is like to see something that is red you cannot know that what happens inside my brain is the same as yours. It may be that “My redness is like your greenness, both of which we call red.” The properties of the red light are the same, but the experience the light produces could be different.

In a collaboration between scientists from Physics and Chemistry at the University of Bayreuth and Physical Chemistry at the University of Melbourne, it has now been possible to realize optically switchable photonic units that enable precise addressing of individual units. This will make it possible to reliably store and read binary information optically.