Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: particle physics – Page 352

A team of researchers from China, Germany and the U.S. has developed a way to create a less fragile diamond. In their paper published in the journal Nature, the group describes their approach to creating a paracrystalline diamond and possible uses for it.

Prior research has shown that diamond is the hardest known material but it is also fragile—despite their hardness, can be easily cut or even smashed. This is because of their ordered atomic structure. Scientists have tried for years to synthesize diamonds that retain their hardness but are less fragile. The team has now come close to achieving that goal.

Currently, the way to create diamonds is to place a carbon-based material in a vice-like device where it is heated to very high temperatures while it is squeezed very hard. In this new effort, the researchers have used the same approach to create a less ordered type of diamond but have added a new twist—the carbon-based material was a batch of fullerenes, also known as buckyballs ( arranged in a hollow spherical shape). They heated the material to between 900 and 1,300 °C at pressures of 27 to 30 gigapascals. Notably, the pressure exerted was much lower than is used to make commercial diamonds. During processing, the spheres were forced to collapse, and they formed into transparent paracrystalline diamonds which could be extracted at room temperature.

Read more | >

Scientists at the Max Planck Institute for the Science of Light (MPL) and Max-Planck-Zentrum für Physik und Medizin (MPZPM) in Erlangen present a large step forward in the characterization of nanoparticles. They used a special microscopy method based on interfereometry to outperform existing instruments. One possible application of this technique may be to identify illnesses.

Nanoparticles are everywhere. They are in our body as , lipid vesicles, or viruses. They are in our drinking water in the form of impurities. They are in the air we breath as pollutants. At the same time, many drugs are based on the delivery of , including the vaccines we have recently been given. Keeping with the pandemics, quick tests used for the detection the SARS-Cov-2 are based on nanoparticles too. The red line, which we monitor day by day, contains myriads of gold nanoparticles coated with antibodies against proteins that report infection.

Technically, one calls something a nanoparticle when its size (diameter) is smaller than one micrometer. Objects of the order of one micrometer can still be measured in a normal microscope, but particles that are much smaller, say smaller than 0.2 micrometers, become exceedingly difficult to measure or characterize. Interestingly, this is also the size range of viruses, which can become as small as 0.02 micrometers.

Read more | >

Computational detective work by U.S. and German physicists has confirmed that cerium zirconium pyrochlore is a 3D quantum spin liquid.

Despite the name, quantum spin liquids are solid materials in which quantum entanglement and the geometric arrangement of atoms frustrate the natural tendency of electrons to magnetically order themselves in relation to one another. The in a quantum spin liquid is so severe that electrons fluctuate between quantum magnetic states no matter how cold they become.

Theoretical physicists routinely work with quantum mechanical models that manifest quantum spin liquids, but finding convincing evidence that they exist in actual physical materials has been a decades-long challenge. While a number of 2D or 3D materials have been proposed as possible quantum spin liquids, Rice University physicist Andriy Nevidomskyy has said there’s no established consensus among physicists that any of them qualify.

Read more | >

Nestled 30 feet underground in Menlo Park, California, a half-mile-long stretch of tunnel is now colder than most of the universe. It houses a new superconducting particle accelerator, part of an upgrade project to the Linac Coherent Light Source (LCLS) X-ray free-electron laser at the Department of Energy’s SLAC National Accelerator Laboratory.

Crews have successfully cooled the accelerator to minus 456 degrees Fahrenheit—or 2 Kelvin—a temperature at which it becomes superconducting and can boost electrons to high energies with nearly zero energy lost in the process. It is one of the last milestones before LCLS-II will produce X-ray pulses that are 10,000 times brighter, on average, than those of LCLS and that arrive up to a million times per second—a world record for today’s most powerful X-ray light sources.

“In just a few hours, LCLS-II will produce more X-ray pulses than the current laser has generated in its entire lifetime,” says Mike Dunne, director of LCLS. “Data that once might have taken months to collect could be produced in minutes. It will take X-ray science to the next level, paving the way for a whole new range of studies and advancing our ability to develop revolutionary technologies to address some of the most profound challenges facing our society.”

Read more | >

Circa 2014 o.o!

When someone mentions “different dimensions,” we tend to think of things like parallel universes – alternate realities that exist parallel to our own, but where things work or happened differently. However, the reality of dimensions and how they play a role in the ordering of our Universe is really quite different from this popular characterization.

To break it down, dimensions are simply the different facets of what we perceive to be reality. We are immediately aware of the three dimensions that surround us on a daily basis – those that define the length, width, and depth of all objects in our universes (the x, y, and z axes, respectively).

Beyond these three visible dimensions, scientists believe that there may be many more. In fact, the theoretical framework of Superstring Theory posits that the universe exists in ten different dimensions. These different aspects are what govern the universe, the fundamental forces of nature, and all the elementary particles contained within.

Read more | >

The development of experimental platforms that advance the field of quantum science and technology (QIST) comes with a unique set of advantages and challenges common to any emergent technology. Researchers at Stony Brook University, led by Dominik Schneble, PhD, report the formation of matter-wave polaritons in an optical lattice, an experimental discovery that permits studies of a central QIST paradigm through direct quantum simulation using ultracold atoms. The scientists project that their novel quasiparticles, which mimic strongly interacting photons in materials and devices but circumvent some of the inherent challenges, will benefit the further development of QIST platforms that are poised to revolutionize computing and communication technology.

The research findings are detailed in a paper published in the journal Nature Physics.

The study sheds light on fundamental polariton properties and related many-body phenomena, and it opens up novel possibilities for studies of polaritonic quantum matter.

Read more | >

The physics of the microrealm involves two famous and bizarre concepts: The first is that prior to observation, it is impossible to know with certainty the outcome of a measurement on a particle; rather the particle exists in a “superposition” encompassing multiple mutually exclusive states. So a particle can be in two or more places at the same time, and you can only calculate the probability of finding it in a certain location when you look. The second involves “entanglement,” the spooky link that can unite two objects, no matter how far they are separated. Both superposition and entanglement are described mathematically by quantum theory. But many physicists believe that the ultimate theory of reality may lie beyond quantum theory. Now, a team of physicists and mathematicians has discovered a new connection between these two weird properties that does not assume that quantum theory is correct. Their study appears in Physical Review Letters.

“We were really excited to find this new connection that goes beyond quantum theory because the connection will be valid even for more exotic theories that are yet to be discovered,” says Ludovico Lami, a member of the physics think-tank, the Foundational Questions Institute, FQXi, and a physicist at the University of Ulm, in Germany. “This is also important because it is independent of the mathematical formalism of quantum theory and uses only notions with an immediate operational interpretation,” he adds. Lami co-authored the study with Guillaume Aubrun of Claude Bernard University Lyon 1, in France, Carlos Palazuelos, of the Complutense University of Madrid, in Spain, and Martin Plávala, of Siegen University, in Germany.

While quantum theory has proven to be supremely successful since its development a century ago, physicists have struggled to unify it with gravity to create one overarching “theory of everything.” This suggests that quantum theory may not be the final word on describing reality, inspiring physicists to hunt for a more fundamental framework. But any such ultimate theory must still incorporate superposition, entanglement, and the probabilistic nature of reality, since these features have been confirmed time and again in lab tests. The interpretation of these experiments does not depend on quantum theory being correct, notes Lami.

Read more | >

We consider dark matter production during the inflaton oscillation epoch. It is conceivable that renormalizable interactions between dark matter and inflaton may be negligible. In this case, the leading role is played by higher dimensional operators generated by gravity and thus suppressed by the Planck scale. We focus on dim-6 operators and study the corresponding particle production in perturbative and non-perturbative regimes. We find that the dark matter production rate is dominated by non-derivative operators involving higher powers of the inflaton field. Even if they appear with small Wilson coefficients, such operators can readily account for the correct dark matter abundance.

Read more | >