Liquid’ light shows social behaviour

Could photons, light particles, really condense? And how will this “liquid light” behave? Condensed light is an example of a Bose-Einstein condensate: The theory has been there for 100 years, but University of Twente researchers have now demonstrated the effect even at room temperature. For this, they created a micro-size mirror with channels in which photons actually flow like a liquid. In these channels, the photons try to stay together as group by choosing the path that leads to the lowest losses, and thus, in a way, demonstrate “social behavior.” The results are published in Nature Communications.

A Bose-Einstein condensate (BEC) is typically a sort of wave in which the separate particles can not be seen anymore: There is a wave of matter, a superfluid that typically is formed at temperatures close to absolute zero. Helium, for example, becomes a superfluid at those temperatures, with remarkable properties. The phenomenon was predicted by Albert Einstein almost 100 years ago, based on the work of Satyendra Nath Bose; this state of matter was named for the researchers. One type of elementary particle that can form a Bose-Einstein condensate is the photon, the light particle. UT researcher Jan Klärs and his team developed a mirror structure with channels. Light traveling through the channels behaves like a superfluid and also moves in a preferred direction. Extremely low temperatures are not required in this case, and it works at room temperature.


The structure is the well-known Mach-Zehnder interferometer, in which a channel splits into two channels, and then rejoins again. In such interferometers, the wave nature of photons manifests, in which a photon can be in both channels at the same time. At the reunification point, there are now two options: The light can either take a channel with a closed end, or a channel with an open end. Jan Klärs and his team found that the liquid decides for itself which path to take by adjusting its frequency of oscillation. In this case, the photons try to stay together by choosing the path that leads to the lowest losses—the channel with the closed end. You could call it “social behavior,” according to researcher Klärs. Other types of bosons, like fermions, prefer staying separate.

The mirror structure somewhat resembles that of a laser, in which light is reflected back and forth between two mirrors. The major difference is in the extremely high reflection of the mirrors: 99.9985 percent. This value is so high that photons don’t get the chance to escape; they will be absorbed again. It is in this stadium that the photon gas starts taking the same temperature as room temperature via thermalization. Technically speaking, it then resembles the radiation of a black body: Radiation is in equilibrium with matter. This thermalization is the crucial difference between a normal laser and a Bose-Einstein condensate of photons.
In superconductive devices at which the electrical resistance becomes zero, Bose-Einstein condensates play a major role. The photonic microstructures now presented could be used as basic units in a system that solves mathematical problems like the Traveling Salesman problem. But primarily, the paper shows insight into yet another remarkable property of light.

Link Original: https://www.scientiststudy.com/2021/10/liquid-light-shows-social-behaviour.html?fbclid=IwAR3x_CZFiidVuOYU4vCFOltF7S54q8WLrTudDchyEf5Q-ZgyHEiOX3js7k8


The secret to regeneration? Scientists say it lies in the axolotl genome.

Few creatures have captured the attention of both the general public and scientists as thoroughly as a peculiar-looking salamander known as the axolotl. Native only to Lake Xochimilco, south of Mexico City, axolotls are less and less frequently found in the wild. However, they are relatively abundant in captivity, with pet enthusiasts raising them due to their alien features, such as the striking, fringy crown they wear on their heads. Researchers also keep a large supply of axolotl in captivity due to the many unique properties that make them attractive subjects of study.

Perhaps the most notable and potentially useful of these characteristics is the axolotl’s uncanny ability to regenerate. Unlike humans and other animals, axolotls don’t heal large wounds with the fibrous tissue that composes scars. Instead, they simply regrow their injured part. 

“It regenerates almost anything after almost any injury that doesn’t kill it,” said Yale researcher Parker Flowers in a statement. This capability is remarkably robust, even for salamanders. Where regular salamanders are known to regrow lost limbs, axolotls have been observed regenerating ovaries, lung tissues, eyes, and even parts of the brain and spinal cord.

Obviously, figuring out how these alien-looking salamanders manage this magic trick is of great interest to researchers. Doing so could reveal a method for providing humans with a similar regenerative capability. But identifying the genes involved in this process has been tricky — the axolotl has a genome 10 times larger than that of a human’s, making it the largest animal genome sequenced to date.

Fortunately, Flowers and colleagues recently discovered a means of more easily navigating this massive genome and, in the process, identified two genes involved in the axolotl’s remarkable regenerative capacity.

A new role for two genes

We’ve understood the basic process of regeneration in axolotls for a while now. After a limb is severed, for instance, blood cells clot at the site, and skin cells start to divide and cover the exposed wound. Then, nearby cells begin to travel to the site and congregate in a blob called the blastema. The blastema then begins to differentiate into the cells needed to grow the relevant body part and grow outward according to the appropriate limb structure, resulting in a new limb identical to its severed predecessor.

But identifying which genes code for this process and what mechanisms guide its actions is less clear. Building off of previous work using CRISPR/Cas9, Flowers and colleagues were able to imprint regenerated cells with a kind of genetic barcode that enabled them to trace the cells back to their governing genes. In this way, they were able to identify and track 25 genes suspected to be involved in the regeneration process. From these 25, they identified two genes related to the axolotls’ tail regeneration; specifically, the catalase and fetub genes.

Although the researchers stressed that many more genes were likely driving this complicated process, the finding does have important implications for human beings — namely that humans also possess similar genes to the two identified in this study. Despite sharing similar genes, the same gene can do very different work across species and within a single animal. The human equivalent gene FETUB, for example, produces proteins that regulate bone resorption, regulates insulin and hepatocyte growth factor receptors, responds to inflammation, and more. In the axolotl, it appears that regulating the regenerative process is another duty.

Since humans possess the same genes that enable axolotls to regenerate, researchers are optimistic that one day we will be able to speed up wound healing or even to completely replicate the axolotl’s incredible ability to regenerate organs and limbs. With continued research such as this, it’s only a matter of time until this strange salamander gives ups its secrets.

Link Original: https://bigthink.com/surprising-science/axolotl-regeneration?rebelltitem=1#rebelltitem1


The ‘X17’ particle: Scientists may have discovered the fifth force of nature

A new paper suggests that the mysterious X17 subatomic particle is indicative of a fifth force of nature.


Physicists have long known of four fundamental forces of nature: gravity, electromagnetism, the strong nuclear force, and the weak nuclear force. 

Now, they might have evidence of a fifth force. 

The discovery of a fifth force of nature could help explain the mystery of dark matter, which is proposed to make up around 85 percent of the universe’s mass. It could also pave the way for a unified fifth force theory, one that joins together electromagnetic, strong and weak nuclear forces as “manifestations of one grander, more fundamental force,” as theoretical physicist Jonathan Feng put it in 2016.

The new findings build upon a study published in 2016 that offered the first hint of a fifth force.

Leer Más

“Regular geometry”

“Regular geometry, the geometry of Euclid, is concerned with shapes which are smooth, except perhaps for corners and lines, special lines which are singularities, but some shapes in nature are so complicated that they are equally complicated at the big scale and come closer and closer and they don’t become any less complicated.” — Benoit Mandelbrot

Explore the fractal geometry of the universe in the free Unified Science Course at ResonanceScience.org

Link Original: Photo: spiderweb on my aloe vera
(photographer unknown: comment for credit)


Supercomputer Aurora 21 will map the human brain, starting in 2021

Between your ears lies a miracle of nature, with more connections than our galaxy has stars. In the past, the idea of mapping the connectome—or the interconnected neuronal pathways of the brain (the white matter), was thought impossible. Now, a group of scientists are planning to do just that. How? They plan on using an oncoming supercomputer with tremendous power. Should they be successful, it could stand as one of the greatest achievements in the history of science. And that’s just one of the project’s scientists at Argonne National Laboratory are planning, with Aurora 21 (A21).

Intel, IBM, and other tech giants are currently working together to create this mind-blowing supercomputer that’ll run a quintillion operations simultaneously. This will be the first exascale supercomputer in the US. It’s set to go live in 2021. Originally, the US Department of Energy (DOE) reported a 2023 unveiling. But when China announced it was to have its own (exascale supercomputer) by 2020, the DOE stepped up its schedule. Those involved with the project say it’s humming along and should be completed on time.

A21 will have a computing power of 1 exaflop. The US, Japan, and China have been in something of a supercomputer arms race. For now, China has the top model, the Sunway TaihuLight in Wuxi. It runs at 200 million billion petaflops. Aurora 21 will surpass this. It’s currently being built at Argonne National Laboratory in Lemont, Illinois.

According to Science Magazine, “IBM and its partner NVIDIA, the makers of Summit, have focused on marrying central processing units (CPUs) with graphical processing units, which are faster and more efficient for calculations involved in complex visual simulations. Intel and Cray, meanwhile, have long aimed to increase the number of CPU ‘cores’ operating in parallel and creating fast links between them.”

xonal nerve fibers in a real brain. Image credit: jgmarcelino from Newcastle upon Tyne, UK, Wikipedia Commons. 

A21 is expected to cost hundreds of millions of dollars. It’ll take up a quarter acre of land, require thousands of miles of wires, and is expected to consume enough power to light a midsize city. Experts say either China or Japan is likely to develop the world’s first exascale supercomputer, but that A21 will make sure the US keeps up with its closest competitors.

There are lots of projects on the docket already, besides mapping the connectome. Others projects include understanding how gases flow during combustion, how galaxies form, and how plasma reacts in a fusion reactor. A21 will also forecast the weather and predict how new medicines might react inside the body. In sum total, it’ll be a huge windfall for physics and science in general.

Neuroscientist Bobby Kasthuri will be a part of this connectome project, some 100 million neurons altogether, approximately. It would do so by piecing together millions of 2-dimensional images to make a 3-dimensional picture of the brain’s white matter. Kasthuri and colleagues plan on mapping a number of different brains, not just one.

They don’t know how much one will vary from the next and they’re excited to see the differences among age groups. Researchers believe the results will give us greater insights into human psychology, thinking, learning, and behavior, and help us better understand all sorts of conditions, such as autism and schizophrenia.

To hear the announcement by the DOE of the creation of this supercomputer, click here:

Link Original: https://bigthink.com/philip-perry/supercomputer-aurora-21-will-map-the-human-brain-starting-in-2021


How do birds navigate? Quantum entanglement suggests

  • Birds’ navigation using Earth’s very faint magnetic fields suggests an incredible level of sensitivity.
  • There’s reason to think that sensitivity may be based on quantum entanglement in cryptochrome in their eyes.
  • Identifying the role of quantum physics in biology could lead, well, who knows where?

Okay, this is far from confirmed, but it’s pretty radical, and exciting. It’s a possible and plausible answer to a question that’s puzzled biologists ever since the manner in which birds navigate became apparent. The question is: How can birds possibly be able to perceive and follow something as faint as the Earth’s magnetic field? The possible answer? It may be that they perceive it through the interaction of entangled quantum particles in their eyes.

Leer Más


Researchers Find Evidence That Human Evolution Is Still Actively Happening

Scientists discover that humans are still evolving, with natural selection weeding out certain diseases.

A large new study says humans are still evolving. Scientists found that natural selection is weeding out harmful genetic mutations from our gene pool.

While we tend to think of evolution as laborious process that takes a long period of time, there also changes that can take place over one or two generations. Researchers from Columbia University analyzed DNA from 210,000 people in the United States and Britain and found that certain genetic variants, particularly those linked to Alzheimer’s disease and heavy smoking appear less frequently in people who live longer. This suggests that such genes are being less favored and may be on the way out of the human genome.

Leer Más