Pulsar timing irregularities reveals hidden gravitational-wave background

29 Jun 2023

Cosmic claims: researchers have used radiotelescopes around the world to hunt for gravitational waves using the subtle variations in the timing of pulsars. (Courtesy: Aurore Simonnet for the NANOGrav Collaboration)

The universe is undulating with a background commotion of gravitational waves that have been emitted by pairs of supermassive black holes. That is according to years’ worth of pulsar observations that have been conducted by several teams of radio astronomers.

Utilizing radio telescopes in the Africa, Asia, Australia, Europe and the US, the teams pioneered the innovative technique of watching for subtle variations in the timing of radio beams from millisecond pulsars.

 

Palladium oxides could make better superconductors

01 Jun 2023 Isabelle Dumé

Superb superconductors? Palladates might have the perfect electronic configuration for high-temperature superconductivity. (Courtesy: M Kitatani et al.)

Palladates – oxide materials based on the element palladium – could be used to make superconductors that work at higher temperatures than cuprates (copper oxides) or nickelates (nickel oxides), according to calculations by researchers at the University of Hyogo, Japan, TU Wien and colleagues. The new study further identifies two such palladates as being “virtually optimal” in terms of two properties important for high-temperature superconductors: the correlation strength and the spatial fluctuations of the electrons in the material.

 

Δυο δρόμοι προς την κβαντική βαρύτητα

BY PHYSICSGG on 25/06/2023 • ( 1 )

● Αν το σύμπαν ξεκίνησε από μια Μεγάλη Έκρηξη, πρέπει να αναθεωρήσουμε τον τρόπο που εφαρμόζουμε την φυσική στην αρχή του χρόνου

● Το μεγάλο ερώτημα είναι πώς; Οι προσπάθειες για την οικοδόμηση μιας θεωρίας που συνδέει την κβαντική φυσική και την σύγχρονη θεωρία της βαρύτητας (την γενική θεωρία της σχετικότητας του Αϊνστάιν) έχουν μέχρι στιγμής αποτύχει.

● Ο μακρύς δρόμος προς τα εμπρός δεν έχει τελειώσει, αλλά έχει δημιουργήσει μερικές πολύ όμορφες ιδέες για την φύση της πραγματικότητας.

Κατά τη διάρκεια του 20ου αιώνα, μάθαμε ότι ο Γαλαξίας μας δεν είναι παρά ένας από τους ‘αμέτρητους’ γαλαξίες στο σύμπαν μας. Μάθαμε επίσης ότι αυτοί οι γαλαξίες απομακρύνονται ο ένας από τον άλλο, μια συλλογική κοσμική διαστολή που την ερμηνεύσαμε ως αποτέλεσμα της διαστολής του χώρου. Αν φανταστούμε τον χρόνο να κινείται προς τα πίσω, αυτοί οι γαλαξίες θα πλησιάζουν όλο και πιο κοντά ο ένας στον άλλον μέχρι να καταλήξουν συμπιεσμένοι σε έναν μικροσκοπικό όγκο. Η θερμοκρασία εκεί είναι τεράστια και η ύλη διασπάται στα στοιχειώδη συστατικά της. Καθώς η συστολή συνεχίζεται, πλησιάζουμε στην αρχή των πάντων – την χρονική στιγμή t = 0 – στην γέννηση του σύμπαντος.

 

Tantalum polyhydride joins emerging class of high-pressure superconductors

19 Jun 2023 Isabelle Dumé

Superconducting transition: Tantalum polyhydride becomes a superconductor at a temperature of 30 K and pressures of around 200 gigapascals. (Courtesy: C Jin)

Tantalum polyhydride becomes a superconductor at a temperature of 30 K and pressures of around 200 gigapascals (GPa), say researchers at the Chinese Academy of Science in Beijing. This marks the first time that superconductivity has been observed in a hydride made from a Group 5 transition metal, and members of the research team say the discovery could pave the way towards synthesizing metallic hydrogen.

 

Is quantum gravity slowing down neutrinos?

21 Jun 2023

Burst detector: the Fermi Gamma-ray Space Telescope. (Courtesy: NASA)

Ultra-relativistic neutrinos blasted into space during gamma-ray bursts are slowed down by the effects of quantum gravity. That is the conclusion of physicists in Italy, Poland and Norway, who have spotted seven neutrinos that arrived on Earth later than expected, compared to their companion gamma rays.

Quantum theory does a fantastic job of describing interactions that involve three out of the four known forces of nature. However, there is no theory today that adequately describes the quantum nature of gravity. While theories of quantum gravity have been proposed, they tend to make predictions that cannot currently be tested by experiment or observation.

Novel breathalyser rapidly tests for COVID-19

 

Novel breathalyzer rapidly tests for COVID-19

14 Jun 2023 Isabelle Dumé

Health monitoring: Qizhong Liang, a PhD candidate in JILA and the University of Colorado Boulder, demonstrates how the laser-based breathalyser works in the Ye lab at JILA. (Courtesy: Patrick Campbell/CU Boulder)

A new medical diagnostic tool based on the use of optical frequency comb technology can rapidly test for COVID-19 in exhaled breath. The technique, developed by researchers at JILA, the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder, could also be used to diagnose other conditions or diseases, particularly those of respiratory, gastrointestinal or metabolic origin.

 

MRI shows potential for verification of proton beam range

15 Jun 2023 Tami Freeman

Seeing the proton beam Top row: relative dose distribution in a water phantom for 200, 207 and 215 MeV proton beams at 32 nA, as measured by radiochromic film. Middle row: MR images showing the residual beam range as a function of beam energy at 32 nA. Bottom row: MRIs showing the beam signal intensity as a function of beam current at 207 MeV. (Courtesy: S Gantz et al PNAS 10.1073/pnas.2301160120)

 

Building blocks of DNA could survive in Venus’ corrosive clouds, say astronomers

17 Jun 2023 Margaret Harris

Acid rain: A Hubble Space Telescope ultraviolet-light image of the planet Venus, showing the sulphuric-acid-rich clouds that cover its surface. (Courtesy: L. Esposito/University of Colorado, Boulder and NASA/ESA)

For a planet sometimes known as “Earth’s twin”, Venus is astoundingly inhospitable. Its surface temperature of 735 K is hot enough to melt lead. Its surface pressure of 94 atmospheres will crush all but the hardiest spacecraft. And if that wasn’t enough, its thick, oppressive clouds drip with sulphuric acid.

 

Graphene’s ‘cousin’ makes a switchable topological insulator

14 Jun 2023 Isabelle Dumé

Germanene, the germanium analogue to graphene. Courtesy: P Bampoulis

Germanene – a two-dimensional, graphene-like form of the element germanium – can carry electricity along its edges with no resistance. This unusual behaviour is characteristic of materials known as topological insulators, and the researchers who observed it say the phenomenon could be used to make faster and more energy-efficient electronic devices.

 

Symmetry breaking in ‘galactic tetrahedrons’ linked to parity violation

13 Jun 2023

Parity violation: image of galaxies taken by the James Webb Space Telescope. Astronomers have found evidence that parity violation in the early universe affects the distribution of galaxies today. (Courtesy: NASA/ESA/CSA/JWST)

Astronomers in the US have discovered an unexpected asymmetry in the relative positions of galaxies that are hundreds of millions of light–years apart. The phenomenon could be explained by a breaking of the symmetry of the laws of nature that is believed to have occurred shortly after the Big Bang. As a result, the observation could help explain why there appears to be much more matter than antimatter in the observable universe.

 

Metalens-based spectrometer fits on a chip

08 Jun 2023 Isabelle Dumé

Metasurface performance: A schematic diagram of the proposed metasurface spectrometer based on a wavelength dependent multi-foci metalens model. (Courtesy: Ruoxing Wang, Muhammad Afnan Ansari, Hammad Ahmed, Yan Li, Wenfeng Cai, Yanjun Liu, Songtao Li, Jianlong Liu, Li Li, and Xianzhong Chen)

A new optical spectrometer is super-compact thanks to a metalens that focuses light at multiple wavelengths. The new device can detect light spectra with a resolution of 1 nm, and unlike its bulkier predecessors, it could be integrated onto a chip, with potential applications in security and information processing.

 

Laser speckle imaging assesses donor hearts

06 Jun 2023 Isabelle Dumé

A powerful tool for screening donor hearts: laser speckle imaging captures detailed images of blood vessels in a beating heart outside the body. (Courtesy: Plyer et al doi 10.1117/1.JBO.28.4.046007)

An imaging technique originally developed to detect how light scatters off red blood cells has been improved by researchers in France so that it can now safely image coronary blood circulation in donor hearts during ex situ heart perfusion (ESHP), a procedure used for heart preservation and screening.

 

CERN physicists meet in London to plot future collider plans

08 Jun 2023 Michael Banks

One ring: The Future Circular Collider, if built, would be a 90 km-circumference particle collider constructed in France and Switzerland (courtesy: D. Dominguez/CERN)

Hundreds of physicists met in London this week for the ninth Future Circular Collider (FCC) Conference. Held at the Millennium Gloucester Hotel London in South Kensington, the five days of talks focused on the latest developments on the FCC – a huge proposed particle collider that would succeed CERN’s Large Hadron Collider (LHC). If built, the collider would cost around £20bn and involve the construction of a 100 km underground tunnel at the current CERN site to house an electron–positron collider (FCC-ee).

 

Dynamic nuclear polarization: how a technique from particle physics is transforming medical imaging

30 May 2023

An experimental technique that started life in nuclear and particle physics is now being used to measure chemical reactions inside the human body and to help diagnose cancer and heart disease in almost 50 clinical trials. Jack Miller charts the unexpected rise of dynamic nuclear polarization, which is vastly improving the quality of magnetic resonance imaging

Powerful probe A brain scan using an experimental technique known as “dissolution dynamic nuclear polarization” (d-DNP). This process can greatly improve the images produced using magnetic-resonance imaging (MRI). (Courtesy: James Grist et al 10.1016/j.neuroimage.2019.01.027 )