We have known for several decades that the universe is expanding. Scientists use multiple techniques to measure the present-day expansion rate of the universe, known as the Hubble constant. These methods are internally consistent and based on the same physics, so all observed values of the Hubble constant should agree. But those that come from early-universe datasets disagree with those that come from late-universe datasets. This problem is known as the Hubble tension and is considered to be one of the most significant open questions in cosmology. 

In JASA, researchers report that the color of a concert hall has an impact on the sound perception of a listener. They created 12 different-colored virtual reality environments, which varied in hues, brightness, and saturation, and used binaural technology that could adjust the sound as participants moved their heads. The participants were asked to rate the performances based on liking, strength, reverberance, and timbre, and the researchers discovered a clear correlation between the visual design of the hall and the perceived timbre of the music.

In AIP Advances, researchers develop a way to remotely fingerprint and identify a cellular device. Using specialized SIM cards and cellular radio standards-compliant base station emulator equipment, the researchers commanded a set of “trusted” cell phones to transmit the exact same sets of signals, allowing them to create a database of what these signals really look like for different phone models. By comparing the signals emitted by an unknown device to the database, the researchers can figure out if the device has been altered.

NYU scientists are using light to precisely control how tiny particles organize themselves into crystals. Their research provides a simple and reversible method for forming crystals that can be used to develop a new generation of adaptable materials.

A team in Belgium led by Professor Dries Van Thourhout reports on a novel type of surface emitting laser, directly integrated on standard 300 mm silicon wafers.  It is based on a one-dimensional array of nano-ridges that forms a photonic crystal cavity, enabling strong in-plane confinement while emitting light vertically. The GaAs photonic crystal is directly grown on the silicon substrate, using a combination of aspect ratio trapping and nano-ridge engineering. By varying the array period and nano-ridge dimensions, the emission wavelength can be controlled.  This is a first step towards a cost-effective alternative for traditional VCSELs, which are today widely used in optical interconnects and consumer products such as mobile phones and optical mice.

Two research teams from the Universitat Jaume I of Castelló and the Public University of Navarre have developed a passive thermoelectric subcooling device for self-contained refrigeration units that improves the efficiency and performance of the refrigeration circuit.

The invention is particularly applicable to the commercial refrigeration sector, specifically to self-contained refrigeration units used to preserve perishable products, as it not only reduces the energy consumption of the equipment but also increases its control capacity.

The new device can be easily integrated into self-contained refrigeration units. It is compact, robust and silent, offers a high level of control thanks to thermoelectric mechanisms, and has no moving parts, which means minimal maintenance. Its main advantages include improved energy efficiency of the refrigeration unit, ease of integration, low maintenance requirements and the absence of noise.

A research team led by the University of Waterloo is developing a novel tool to treat cancer by engineering hungry bacteria to literally eat tumours from the inside out. Bacteria spores enter the tumour, finding an environment where there are lots of nutrients and no oxygen, which this organism prefers, and so it starts eating those nutrients and growing in size.