Lifeboat Foundation

Researchers produce analogues of hard-to-study quantum phenomena in a gas of strontium atoms near absolute zero.

Recently, researchers have begun using ultracold atomic gases to simulate phenomena that are difficult to study in their natural environments. Using electromagnetic fields, for example, they can orchestrate interatomic interactions that are analogous to interactions in condensed-matter systems, which they can then study with greater experimental control than the real examples allow. Now David Wilkowski of Nanyang Technological University in Singapore and colleagues use an ultracold atomic gas to simulate a condensed-matter system’s spin dynamics [1].

Wilkowski’s team cools a gas of strontium-87 atoms to 30 nK. Then, using three convergent laser beams, they drive the gas through various transitions until the atoms populate two so-called dark states, in which quantum mechanics forbids the atoms from undergoing spontaneous emission.

Researchers have demonstrated that a solid can exhibit an enhanced nonlinear optical phenomenon usually seen only in cold atomic gases.

Among the benefits brought about by the invention of the laser in the 1960s is the ability to generate light at an intensity great enough to produce nonlinear optical effects. Such nonlinear effects have entered daily use in applications that include infrared-to-visible-light wavelength conversion (in a green laser pointer, for example) and two-photon excitation (in fluorescence microscopes for observing biological living tissue). Now Corentin Morin of the École Normale Supérieure in Paris and colleagues address a third-order nonlinear process called the Kerr effect, which manifests as a change in a material’s refractive index when it is illuminated with light of different intensities [1]. The researchers demonstrate a giant Kerr nonlinearity in a solid, a state of matter that has, until now, exhibited only a weak Kerr effect. The result implies the possibility of scalable nonlinear quantum optics without the need of cold atoms in high vacuum.

The key to the discovery by Morin and colleagues is a quasiparticle called a Rydberg exciton, the understanding of which rests on two concepts. The first concept is the Rydberg series, which is the discrete energy-level structure available to an atom’s outermost electron, and which is indexed by the principal quantum number n. A high-lying Rydberg state has a large n and exhibits properties such as a large electron orbital radius, a long lifetime, and a large dipole moment, all of which are missing in the ground state. The second concept is a hydrogen-atom-like quasiparticle called an exciton—a negatively charged electron, photoexcited across a semiconductor’s band gap, Coulomb-bound to a positively charged hole left in the valence band.

Ancient Palmyra has gripped public imagination since its picturesque ruins were “rediscovered” in the seventeenth century by western travelers. The most legendary story of ancient Palmyra is that of Queen Zenobia, who was ruling over a thriving city in the Syrian Desert and dared to challenge the Roman Empire, but ultimately was defeated.

Her kingdom was subjugated, and the city was reduced to a small settlement without any wide-ranging importance. This has only recently been overshadowed by the catastrophic events of the Syrian Civil War that saw the archaeological site and the museum plundered and many monuments destroyed.

The technology, which has been tested in the lab, could ultimately be used for manufacturing and building in difficult-to-access or dangerous locations such as tall buildings or help with post-disaster relief construction, say the researchers.

3D printing is gaining momentum in the construction industry. Both on-site and in the factory, static and mobile robots print materials for use in construction projects, such as steel and concrete structures.

Continue reading “3D-printed drones work like bees to build and repair structures while flying” »

A study led by Durham University’s Fetal and Neonatal Research Lab, UK, took 4D ultrasound scans of 100 pregnant women to see how their unborn babies responded after being exposed to flavors from foods eaten by their mothers.

Researchers looked at how the fetuses reacted to either carrot or kale flavors just a short time after the flavors had been ingested by the mothers.

Fetuses exposed to carrot showed more “laughter-face” responses while those exposed to kale showed more “cry-face” responses.

From the same mind whose research propelled the notion that “sitting too much is not the same as exercising too little,” comes a groundbreaking discovery set to turn a sedentary lifestyle on its ear: The soleus muscle in the calf, though only 1% of your body weight, can do big things to improve the metabolic health in the rest of your body if activated correctly.

And Marc Hamilton, professor of Health and Human Performance at the University of Houston, has discovered such an approach for optimal activation—he’s pioneering the “soleus pushup” (SPU) which effectively elevates muscle metabolism for hours, even while one is sitting. The soleus, one of 600 muscles in the human body, is a posterior leg muscle that runs from just below the knee to the heel.

Continue reading “Researcher discovers a muscle that can promote glucose and fat burning to fuel metabolism for hours while sitting” »

Researchers investigated the polarization-dependence of the force exerted by circularly polarized light (CPL) by performing optical trapping of chiral nanoparticles. They found that left-and right-handed CPL exerted different strengths of the optical gradient force on the nanoparticles, and the D-and L-form particles are subject to different gradient force by CPL. The present results suggest that separation of materials according to their handedness of chirality can be realized by the optical force.

Chirality is the property that the structure is not superimposable on its mirrored image. Chiral materials exhibit the characteristic feature that they respond differently to left-and right-circularly polarized light. When matter is irradiated with strong laser light, optical force is exerted on it. It has been expected theoretically that the optical force exerted on chiral materials by left-and right-circularly polarized light would also be different.

Continue reading “Differentiating right- and left-handed particles using the force exerted” »

Florida’s “silent” flying dish-rack, powered by ionic propulsion, is on track for commercial rollout in 2024, according to Undefined Technologies, which has released new outdoor flight test video. We remain curious, but unconvinced it’ll be viable.

The “Silent Ventus” drone doesn’t use propellers to fly. Instead, its entire broad structure creates two stacked grids of electrodes, designed to create high-voltage electric fields that can ionize the oxygen and nitrogen molecules in the air, freeing electrons to give them a positive charge, and then propelling these downward to create an “ionic wind” that can produce thrust.

Continue reading “Undefined claims 4.5-min flight for its ‘silent’ ion-propulsion drone” »

Small but mighty, lysosomes play a surprisingly important role in cells despite their diminutive size. Making up only 1–3% of the cell by volume, these small sacs are the cell’s recycling centers, home to enzymes that break down unneeded molecules into small pieces that can then be reassembled to form new ones. Lysosomal dysfunction can lead to a variety of neurodegenerative or other diseases, but without ways to better study the inner contents of lysosomes, the exact molecules involved in diseases—and therefore new drugs to target them—remain elusive.

A new method, reported in Nature on Sept. 21, allows scientists to determine all the molecules present in the lysosomes of any cell in mice. Studying the contents of these molecular recycling centers could help researchers learn how the improper degradation of cellular materials leads to certain diseases. Led by Stanford University’s Monther Abu-Remaileh, institute scholar at Sarafan ChEM-H, the study’s team also learned more about the cause for a currently untreatable neurodegenerative disease known as Batten disease, information that could lead to new therapies.

“Lysosomes are fascinating both fundamentally and clinically: they supply the rest of the cell with nutrients, but we don’t always know how and when they supply them, and they are the places where many diseases, especially those that affect the brain, start,” said Abu-Remaileh, who is an assistant professor of chemical engineering and of genetics.