When a gas is highly energized, its electrons get torn from the parent atoms, resulting in a plasma—the oft-forgotten fourth state of matter (along with solid, liquid, and gas). When we think of plasmas, we normally think of extremely hot phenomena such as the sun, lightning, or maybe arc welding, but there are situations in which icy cold particles are associated with plasmas. Images of distant molecular clouds from the James Webb Space Telescope feature such hot–cold interactions, with frozen dust illuminated by pockets of shocked gas and newborn stars.
Now a team of Caltech researchers has managed to recreate such an icy plasma system in the lab. They created a plasma in which electrons and positively charged ions exist between ultracold electrodes within a mostly neutral gas environment, injected water vapor, and then watched as tiny ice grains spontaneously formed.
They studied the behavior of the grains using a camera with a long-distance microscope lens. The team was surprised to find that extremely “fluffy” grains developed under these conditions and grew into fractal shapes—branching, irregular structures that are self-similar at various scales. And that structure leads to some unexpected physics.
A joint effort between two of the world’s largest neutrino experiments has brought scientists closer to understanding how the universe survived its violent beginnings.
The findings could reveal why matter exists at all — and why everything didn’t vanish long ago.
Scientists unite to explore why the universe exists.
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Spintronics is short for “spin electronics,” and refers to the study of the spin of the electron. In electronic devices, spintronics leverages the spin of electrons to process and store data with extreme efficiency – this technology is just a few years from reaching the consumer market, and will make your devices faster and more efficient. For a price, of course. Let’s take a look at how spintronics got here and where it’s going.
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Neutron stars are ultra-dense star remnants made up primarily of nucleons (i.e., protons and neutrons). Over the course of millions of years, these stars progressively cool down, radiating heat into space.
The cooling process of neutron stars could be a promising testbed for various hypothetical particles, including so-called scalar particles. These are particles that do not possess a spin and that, according to some theoretical predictions, could couple to nucleons.
Scalar particles are hypothesized to violate two fundamental laws of gravity, known as the equivalence principle and the inverse-square law. Their observation could thus greatly enrich the present understanding of the universe and its underlying physical forces.
A team from the Faculty of Physics and the Center for Quantum Optica l Technologies at the Center of New Technologies, University of Warsaw has developed a new method for measuring elusive terahertz signals using a “quantum antenna.”
The authors of the work utilized a novel setup for radio wave detection with Rydberg atoms to not only detect but also precisely calibrate a so-called frequency comb in the terahertz band. This band was until recently a white spot in the electromagnetic spectrum, and the solution described in the journal Optica paves the way for ultrasensitive spectroscopy and a new generation of quantum sensors operating at room temperature.
Terahertz (THz) radiation, being part of the electromagnetic spectrum, lies at the boundary of electronics and optics, positioned between microwaves (used, for example, in Wi-Fi) and infrared.
Trapped neutral atoms are an attractive platform for quantum computing, as large arrays of atomic qubits can be arranged and manipulated to perform gate operations. However, the loss of useable atoms—either from escape or from disturbance—can be a limitation for long computations with repeated measurements. Researchers at Atom Computing, a company in California, have devised a “reset or reload” protocol that mitigates atom losses [1]. The method was successfully employed during a computation consisting of 41 cycles of qubit measurements.
All current quantum computers require error correction, which involves measuring certain qubits at intermediate steps of a computation. Reusing these qubits would avoid needing a prohibitively high overhead in qubit numbers, says team member Matthew Norcia. But in the case of atoms, the process of resetting measured qubits risks disturbing unmeasured ones.
To overcome this challenge, the researchers have developed a way to shield unmeasured atoms from the resetting process. They use targeted laser beams to immunize the unmeasured atoms against excitation by shifting their resonances. They then turn on a second set of lasers that cool the measured atoms and reinitialize them, enabling them to join the unmeasured atoms in the next computational step.
Their findings have been published in the journal Advanced Functional Materials in an article titled “Long-Lasting Moisture Energy Scavenging in Dry Ambient Air Empowered by a Salt Concentration-Gradient Cationic Hydrogel.”
How the new MEG technology works These moisture-activated generators (or MEGs) work by creating a flow of ions—charged particles—inside a special gel, generating power naturally. But current versions face challenges: they don’t last long (less than 16 hours), have high internal resistance, and only work well in very humid conditions.
Professor Shin and his team have overcome those hurdles. They developed a salt-concentration-gradient cationic hydrogel for MEG, promising lower energy loss and higher output even in conditions of low relative humidity.
If you look across space with a telescope, you’ll see countless galaxies, most of which host large central black holes, billions of stars and their attendant planets. The universe teems with huge, spectacular objects, and it might seem like these massive objects should hold most of the universe’s matter.
But the Big Bang theory predicts that about 5% of the universe’s contents should be atoms made of protons, neutrons and electrons. Most of those atoms cannot be found in stars and galaxies—a discrepancy that has puzzled astronomers.
If not in visible stars and galaxies, the most likely hiding place for the matter is in the dark space between galaxies. While space is often referred to as a vacuum, it isn’t completely empty. Individual particles and atoms are dispersed throughout the space between stars and galaxies, forming a dark, filamentary network called the “cosmic web.”