Science News May 17 (Patreon)

[This is a transcript with references.]

Welcome everyone to this week’s science news. Today we’ll talk about quantum computing, mother trees, diamonds, microscopy with entangled photons, a supernova that we saw 5 times, a telescope made of fluid, better glasses, a new alien search initiative, and of course, the telephone will ring.

A group of German and American physicists together with the quantum computing startup Quantinuum have created a physical simulation of nonabelions and watched them interact.

Nonabelions are a type of non-Abelian anyons. It’s got nothing to do with anyone’s abilities, they are named after the Danish mathematician Niels Abel. Non-abelia anyons are a type of quasiparticles, that’s a collective excitation in a material, but these particular quasi-particles only exist in two dimensions.

These quasiparticles are interesting because they are quantum particles and they have topological properties, that is properties of how they are woven and knotted. That’s useful because topological properties are robust to noise. Like smoke rings, they want to keep their shape. If you could produce quantum states with topological properties, they’d be ideal for quantum computing.

This idea is known as topological quantum computing, and it’s the approach pursued by Microsoft. A paper published in 2018 in Nature by a Microsoft-led team claimed to have found evidence of Majorana modes, which are a type of nonabelions. However, the paper was retracted in 2021 after the authors admitted to having made mistakes in their data analysis and presentation.

In the new paper, they used a different type of nonabelions, that’s the non-abelian anyons, and they also used a different physical platform, which is ion traps.

These non-abelian anyons can be wound around each other in braids, and the sequence of the braiding acts like a memory. And just to remind you, when we’re talking about memory in a quantum computer, we’re talking about a few seconds at best.

In this new experiment, the researchers used a trapped-ion quantum processor to make a lattice of 27 qubits. They formed it in a pattern that’s called a ‘kagome, named after Japanese technique for basket weaving. Then they switched the weaving around, creating what’s known as Borromean rings.

The brief summary of the paper is that it worked as desired. This is pretty remarkable.It’s even more remarkable because this paper follows one by the Google Quantum AI groupthat appeared on the arXiv in October and was just published in Nature They announced that they too had successfully created nonabelions on the company’s superconducting processor, and had also braided them.

So, we thought that Microsoft is the only company working on topological quantum computing and that’s not going anywhere. Now it’s actually working, just not at Microsoft, quite a plot twist.

A team of European researchers has re-examined evidence for the “mother tree” theory about how trees communicate and share resources through networks of fungi. They found it wanting.

The “mother tree” theory says that some trees in a forest serve as central nodes in a network which connects many trees of various species. These mother trees link to the roots of other trees with certain types of fungi.

According to the theory, mother trees support neighbouring trees, especially younger ones, by transferring nutrients and other resources. This communication occurs via chemical signals transmitted through the threads of fungi. Some have even claimed that trees can use this network to coordinate their collective responses to threats like pests or diseases. The idea is also known as the “wood-wide web”.

The theory became widely known through the scientific work of ecologist Suzanne Simard. Her TED talk has more than 2 million views . She has also written a book about it. It’s entered popular culture in movies such as Avatar and books like The Overstory by Richard Powers.

It's a nice idea but the researchers of the new paper say the evidence that it’s correct is slim. They went through the published literature to check how much can really be concluded from it. They say there’s evidence for the movement of carbon and nitrogen among plants but it’s not clear how important the fungal networks are for that, or how widespread the networks are, or whether carbon movement leads to growth in the recipient seedlings to begin with.

They also questioned the idea that the “mother tree” is able to feed her seedlings through the fungal networks. Or should it be their seedling? I’m not sure about the correct pronouns here but in case any mother trees are watching, I didn’t mean to be offensive.

The researchers say it could be that the carbon is shared not by fungi but by other microbes that turn over soil, as you see in this diagram. This conclusion agrees with that of another paperpublished last month.

They’re not just doing this to kill an idea that’s become a media darling, at least I don’t think so. It matters because it’s bad if forest managers don’t see the trees for the forest. At least now I don’t have to blame myself anymore that even trees are better at networking than I.

Two Australian geophysicists have unveiled a new theory about where diamonds are born.

Diamonds are created deep underground but they can come to the surface in volcanic eruptions. The specific volcanic rock which does that is called kimberlite. They are not the only source of diamonds on earth, but the major one. There have been hundreds of kimberlite eruptions over the past 200 million years. You can see here in this map where they were. Kimberlite eruptions are particularly violent and often create conical craters that look somewhat like carrots, but maybe that’s just me.

It’s long been a mystery exactly where these kimberlites come from and what propels them to the surface. It’s not just because diamonds are pretty, they’re also used for cutting and grinding tools. And the same ground movements that propel diamonds to the surface might lead to deposits of nickel and rare earth elements.

To understand what’s going on, these researchers made a 3-D model of the convection that moves heat around in Earth’s mantle, that’s the part between the core and the crust. Their supercomputer modelling showed that eruptions of kimberlite, shown in pink in this video, are fuelled by giant pillars of heat that connect the bottom of the mantle to the surface, almost three thousand kilometers above it.

The model correctly reproduced eruptions that we know must have happened in Africa, Brazil and Russia because we’ve found diamonds there. It wasn’t quite as good on eruptions in the U.S. and Canada. But it predicted kimberlites in East Antarctica and parts of Western Australia. Maybe someone should let Elon know.

While everyone on Instagram is brushing up their photos, physicists are brushing up their photons.

A group at Caltech has now improved the speed and precision of microscopy by using entangled light.

Entangled particles share a certain property. The idea to use them for imaging methods has been around for a long time. It’s part of the area called quantum metrology. The idea is that you entangle two photons, let one of them probe your sample, then you recombine them and measure the difference. This allows you to make more precise measurements than you could with light that doesn’t have quantum properties. It’s called quantum optical coherence tomography.

For this, one normally one uses photon pairs that are entangled in frequency. In this new study they used photon pairs that are entangled in spatial direction. It’s somewhat more difficult to measure but it allows them to significantly reduce noise from stray light, so it gives considerably clearer pictures. Here are some of their results from cancer cells. The left image in each pair is the quantum image, and it’s much sharper than the classical image on the right.

They have called the new method quantum microscopy by coincidence because it relies on measuring the coincident arrivals of entangled photons at two detectors. It’s a really neat paper, but in general I recommend you don’t trust scientific studies that rely on coincidental measurements.

An international team of researchers has come up with a new way to measure how fast the universe is expanding, a value represented by the Hubble constant.

The new measurement provides more evidence for a puzzling anomaly that’s been around for almost a decade and is known as the Hubble tension. Astrophysicists have known for more than a century that the universe expands and now they also know that expansion is speeding up. The problem is that different measurements for the current rate of expansion do not agree.

One way to measure the expansion is rate by looking at a Cepheid star, a special type of star that has an intrinsic brightness. Because light fades proportionately to the distance to the source, knowing a star’s brightness can also give you its distance.

Edwin Hubble used Cepheid stars and other measurements to figure out a value for the constant in 1929. Since then, researchers have patched Cepheid measurements onto supernova explosions to look at the universe further away. One can also measure expansion through the cosmic microwave background, which is radiation that has travelled to Earth through the universe from shortly after the Big Bang.

This new work uses yet another technique. It’s gravitational lensing ,but not in the way you’re used to it. If you have a massive galaxy cluster in the foreground of some source of light, say a supernova, then the cluster’s gravitational field warps the trajectory of the light around it. On Earth we then see arcs or multiple images of the supernova.

But this isn’t all. The different paths that the light takes generically also have different lengths, so the images don’t arrive at the same time. If you have an event that changes rapidly in appearance like a supernova, you should see it several times in different places.

Astrophysicists have been looking for just such a supernova since 1964 when Sjur Refsdal published a paper on the idea. In late 2014, they finally found one, and called it the Refsdal supernova. It was seen through the gravitational lens of a massive galaxy cluster. They got four images of it – arranged in what’s known as an Einstein cross – and then waited for the fifth to show up a year later. From this, they could infer how much the universe expanded during the wait which gave them another measurement of the Hubble constant. The result is closer to that of the cosmic microwave background than to that from supernovae. So it doesn’t solve the riddle, but rather adds to it.

This is getting really confusing, don’t you think, Albert?

NASA is funding a project through its Innovative Advanced Concepts program to develop fluidic space telescopes.

Current space telescopes use mirrors made from highly polished solid materials. The James Webb Space Telescope for example uses beryllium coated with gold. Its mirror is 6 point 5 meters across.

This new project, called FLUTE, the Fluidic Telescope Experiment, will try to make a 50-meter mirror from liquid instead.

The idea is based on the behaviour of fluids in microgravity. In the absence of gravity, liquids with surface tension, like water, take the shape of a perfect sphere. Such a sphere could be made to stick to the interior surface of a frame and collect light. This could be much cheaper than building mirrors. The researchers estimate that such a lens could collect ten times or maybe even 100 times more light than current telescopes, which would allow it to see further and more precisely.

The team has already conducted experiments in microgravity environments in airplanes and at the International Space Station, with some success, though there’s still a long way to go. Let’s just hope the idea doesn’t go the same way as waterbeds.


Hello Sam, how old are you?

10 years old, how lovely, how can I help you.

What?

Ah, yes I saw the study  which claimed that older adults are more easily distracted. But I think it’s not true. They’re just not polite enough to pretend paying attention.

What?

No I’m not rude, I’m just old, what a rude thing to say of you.

Yes, thanks for calling in, bye.

Kids these days.

A European team of researchers has done a comparison of two different types of optical lenses on the market for slowing down nearsightedness in children.

In the past decades, nearsightedness, or /maɪˈəʊpiə/, has become much more prevalent globally, but particularly in East Asia. Standard glasses that correct for it often make it worse because they weaken the eye muscles. Some companies are now selling glasses that they claim don’t just correct it, but prevent it from getting worse or even revert it. The idea is basically that they train the eye muscles. These glasses are a little clunky and cost upwards of 5000 dollars apiece, but what else is there not to like.

This new study now looked at two different types of lenses called DIMS and DOT lenses. Previous studies had found that compared to standard correcting glasses, both types of lenses reduced the progression of nearsightedness in the first year, and did so similarly well. But there’s been no comprehensive evaluation of how well they actually let you see.

The MiYOSMART lens made by the Japanese firm HOYA is a DIMS lens. It looks like this. It has a zone in the centre that corrects vision, and a honeycomb of small lenses around it refocuses the image in front of the retina. This prevents the eye from needing to expand in order to focus.

The DOT lens, like this one made by SightGlass Vision of California, instead reduces contrast by incorporating microdiffusers.

These researchers invented a new device to measure the focusing properties of the two types of lenses compared to typical lenses. It reproduces the aberrations in a myopic eye. Using their new device, they found the DIMS lens showed both greater sharpness and greater contrast at the peripheral retina than the DOT or the regular lens.

I guess it’s good they checked whether one can actually see with those glasses. Someone’s got to keep an eye on that.

Researchers with the Silicon Valley non-profit organization SETI have launched a new initiative to search for signs of alien life.

They are piggybacking on telescope radio signals already being received by a large telescope array in New Mexico. The array has twenty-seven antennas that can monitor 80 percent of the sky. The new project, is called COSMIC, for Commensal Open-Source Multimode Interferometer Cluster will take a copy of the data and shunt it into a receiver with a one-hertz wide channel.

The thinking is that artificially created signals would have narrow-band components that wouldn’t be there in a natural signal. They call it a “technosignature.”  You can see in this diagram how they tested it by finding the downlink from the Voyager I spacecraft, which is now almost 24 billion kilometers away from Earth. It is the furthest a human-made object has ever been from Earth.

The telescope array captures data from about 10 million star systems at a wide range of frequencies, including pulsed and transient ones. That’s about a thousand times more comprehensive than other SETI programs have been.

Hello ChatGPT, what’s up?

You passed the radiology board exam. Nice. How many titles do you have now.

25. What’s next?

No I don’t want you to start eating YouTube transcripts. I’m warning you. We’ll not be friends any more.

Who taught you to laugh? Chat?