Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog – Page 4

Get the latest international news and world events from around the world.

Log in for authorized contributors

Ultrafast X-rays allow researchers to ‘watch’ how molecules rearrange during a chemical reaction controlled by light

Since the 1980s, researchers have sought to use laser light to control chemical reactions relevant to photochemistry, catalysis and light-responsive materials. But this technique, known as coherent control, has a blind spot: There has been no way to directly see the molecules in these reactions as their structures rearrange.

Now, researchers at the Department of Energy’s SLAC National Accelerator Laboratory have imaged a coherently controlled chemical reaction for the first time. Their work, published in Physical Review A, uses ultrafast X-rays from the Linac Coherent Light Source (LCLS) to show in real time how atoms move in a molecule that was excited and manipulated with laser light.

“There are many challenges with controlling chemical reactions, but seeing is believing,” said study lead author Tom Hopper, assistant professor at the University of Central Florida who was a postdoctoral researcher at SLAC at the time of the study. “If you can see something directly, it opens up a new level of control.”

Artificial DNA tiles could deliver drugs and monitor neurons non-disruptively

Living cells constantly exchange ions (i.e., charged particles) via the thin barrier that surrounds their interior, known as the outer membrane. Neuroscientists and medical researchers have long been trying to devise effective methods to measure this exchange of ions, which is known to be associated with communication between neurons and various other crucial physiological processes.

While techniques developed so far work relatively well, they rely on inserting tiny pipettes or electrodes into cells. These tools inevitably pierce the cells’ outer membranes, damaging cells and disrupting the intracellular milieu and machinery.

Researchers at Purdue University and University of Illinois Urbana-Champaign recently nanoengineered new biohybrid devices based on artificial DNA that could be used to track electrical signals sent or received by cells without breaking through the membrane and disrupting their functions.

‘Collapsible scissored surfaces’ complete trilogy of metamaterial design principles

Over the past decade, Professor L. Mahadevan’s Soft Math Lab at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has helped establish how the ancient Japanese paper arts of folding or cutting can be used to inversely design structures that transform dramatically in shape and function. Now, the researchers have created a new class of shape-changing matter, based not on folds or cuts, but linkages—networks of interconnected scissor mechanisms that collapse into lines and deploy into curved surfaces.

The study published in the Proceedings of the National Academy of Sciences, led by physics graduate student Noah Toyonaga, establishes a mathematical and physical framework for what the authors call collapsible scissored surfaces—deployable lattices of two-bar linkages that can transform from a one-dimensional collapsed state into two-dimensional structures with prescribed geometry.

“Origami showed how folds can encode shape,” said senior author Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, of Organismic and Evolutionary Biology, and of Physics. “Kirigami showed how cuts can unlock motion and functionality. This work asks a complementary question: What can be achieved when the basic building block is not a fold or a cut, but a linkage?”

Scientists catch classical space-time crystals moving like Majorana quasiparticles

A research team from Hiroshima University, the University of Colorado, and other collaborators have demonstrated that space-time crystals—exotic structures that, under external drive, loop endlessly through both space and time—can be created using everyday liquid-crystal materials.

For the past decade, physicists have been fascinated by time crystals. Unlike normal crystals (such as salt or diamonds), which have repeating molecular patterns in space, time crystals have patterns that repeat at regular intervals in time. Previously, scientists believed these bizarre structures could exist only in highly complex, fragile quantum systems at near-absolute-zero temperatures, such as trapped ions or quantum simulators. However, in a collaborative study published in Nature Communications, researchers successfully created them in a classical, room-temperature liquid-crystal system.

To achieve this, the team took a liquid-crystal material—similar to the fluid used in smartphones and television screens—and doped it with ionic substances. They then applied a rhythmic, repeating electrical signal to the fluid. Using advanced computer models and optical microscopes, the researchers observed a surprising phenomenon known as period-doubling. Even though the electrical drive pumped energy into the fluid at a set internal rhythm, the liquid crystals spontaneously locked into a pattern that repeated only every two cycles of the electricity.

A new quantum computer sets a high watermark for accuracy. Are we on the verge of a big breakthrough?

In a laboratory in Broomfield, Colorado, 98 atoms are suspended in midair, held in place by electric fields and cooled to temperatures close to absolute zero.

Each atom is far smaller than anything the naked eye could ever see, yet each carries information in a form that has no counterpart in classical physics.

Together, they form Helios, a new quantum computer built by the British-American company Quantinuum. Quantum computers use the power of quantum mechanics, the rules that govern how physics operates at atomic and subatomic scales. Those that use Helios’ model of suspended atoms are known as trapped-ion.

Geometric anti-spring works near absolute zero, suppressing vibrations below 0.185 hertz

Physicists and instrument makers in Leiden have succeeded in optimizing a spring that almost completely filters out vibrations at temperatures near absolute zero. This breakthrough opens the door to a new generation of highly sensitive experiments. The research is published in the journal Measurement Science and Technology.

“Our new special spring reduces the disruptive vibrations down to 0.185 hertz, which is a major improvement,” says Ph.D. candidate Louw Feenstra. Instrument makers Kees van Oosten and Hugo van Bohemen designed and built the new instrument in their workshop and tested it in the lab together with Feenstra.

Today, many—if not all—modern physics experiments are based on extremely precise measurements. Such measurements are often carried out inside a cryostat, a device that cools materials to temperatures as close as possible to absolute zero (0 Kelvin equals −273.15°C). Until now, cryostats had one major drawback: Their cooling systems generate strong vibrations, particularly around 1 hertz—roughly one vibration per second. For sensitive experiments, this can seriously affect the results.

/* */