Discovery of topological LC circuits transporting EM waves without backscattering

December 28, 2018, National Institute for Materials Science
Discovery of topological LC circuits transporting EM waves without backscattering
Microstrip arrays used in this research. Credit: NIMS

NIMS has succeeded in fabricating topological LC circuits arranged in a honeycomb pattern where electromagnetic (EM) waves can propagate without backscattering, even when pathways turn sharply. These circuits may be suitable for use as high-frequency electromagnetic waveguides, which would allow miniaturization and high integration in electronic devices such as mobile phones.

Researchers are seeking topological properties with functions that are not affected even if the sample shapes are changed. Topological properties were first discovered in electron systems, and more recently, the notion has been developed for light and microwaves for building optical and electromagnetic waveguides immune to backscattering. However, realization of topological properties in light and microwaves normally requires gyromagnetic materials under an , or some other . In order to match existing electronics and photonics technologies, it is important to achieve topological properties based on conventional materials and simple structures.

In 2015, this  demonstrated topological properties in light and microwaves in a honeycomb lattice of dielectric cylinders such as silicon. This time, the team reported that in a microstrip,  attain topological properties when the metallic strips form a  and the intra-hexagon and inter-hexagon strip widths are different. The team also fabricated microstrips and measured electric fields on their surfaces, and successfully observed the detailed structure of topological electromagnetic modes, where vortices of electromagnetic energy polarized in a specific direction are generated during the .

This research demonstrates that topological propagation of electromagnetic waves can be induced using conventional materials in a simple structure. Because topological electromagnetic wave propagation is immune to backscatter even when pathways turn sharply, designs of compact electromagnetic circuits become possible, leading to miniaturization and high integration of electronics devices. In addition, the direction of vortex and the vorticity associated with topological electromagnetic modes may be used as data carriers in high-density information communications. All these features may contribute to the development of advanced information society represented by IoT and autonomous vehicles.

 Explore further: Topological photonic crystal made of silicon

More information: Yuan Li et al, Topological LC-circuits based on microstrips and observation of electromagnetic modes with orbital angular momentum, Nature Communications (2018). DOI: 10.1038/s41467-018-07084-2

Read more at:

Chrome OS code suggests Google plans to migrate Messages web app to


It appears Google plans on migrating its Messages web app from to, according to a Chromium Gerrit code edit spotted by 9to5Google. The code in question is a switch that instructs Chrome OS devices to visit — instead of — when users take advantage of the platform’s “Better Together” functionality. At the time of writing, isn’t active, though that could change over the next few weeks. It’s likely Google will keep both domains active for at least a couple of weeks while it migrates users to the former. The move comes part of a wider initiative by Google to reduce the visibility of Android as a major part of its brand arsenal. For instance, the company did not mention the operating system when it announced the Pixel 3 and 3 XL in October 2018. In the case of Messages, the SMS app was called Android Messages until recently. And in yet another example: at the start of this year, Google rebranded Android Pay to Google Pay.

Read more at MobileSyrup.comChrome OS code suggests Google plans to migrate Messages web app to

HomeKit Weekly: Nanoleaf Light Panels versus Canvas — interactive smart lighting comparison

Nanoleaf HomeKit lights are great for decorating and entertaining all year — long after the Christmas tree is taken down and the holiday lights are all boxed up. Nanoleaf now makes two styles of smart lights that illuminate your walls: Light Panels and Canvas. Here’s how they compare:

Nanoleaf Light Panels ($229), originally called Aurora, are triangular tiles that connect using a modular system to create colorful light designs that you can control with Siri or an iOS app. My description from December 2016 still holds up:

Nanoleaf Aurora is like a beautiful screensaver for your wall.

Nanoleaf has since added a new music module accessory that makes Light Panels react to music and sound, and the Nanoleaf Remote adds to the ways you can trigger modes.

Nanoleaf Canvas ($249) launched earlier this month and reshapes what you can do with Nanoleaf HomeKit lights. Canvas tiles are a bit smaller and use squares instead of triangles to make different designs possible. The music module is also built-in so interactive sound scenes work out-of-the-box.

Both smart light systems let you create colorful scenes that you can trigger with HomeKit using Siri or the Home app. Just add a pre-configured scene from the Nanoleaf app or create your own, then the scene becomes available with HomeKit.

The blue/red/orange/yellow/white arrangement (above, left) is a rocket scene I created for Light Panels that doesn’t change colors. You can also easily switch to a color-shifting scene (and back again) as seen below:

Nanoleaf Canvas similarly supports color-shifting scenes. (Both scenes sped up 4x for demonstration purposes.)

The triangular Light Panels are a bit larger and let you easily create designs with angled corners like stars, trees, or even rocket ships. The smaller Canvas squares won’t cover as much surface area without more tiles, but you can design more traditional patterns with similar light effects.

Light Panels are powered by a controller module that includes a power toggle and a scene selector. Canvas is a bit more clever and integrates power, brightness, and mode switching in a special tile with labeled touch controls.

The other trick that Nanoleaf Canvas has up its sleeve is that each tile can react to touch. Nanoleaf Canvas supports special interactive scenes that let you play games with your tile arrangement with scenes including “Whack A Mole”, “Simon”, “Game Of Life”, “Memory”, and “PacMan.”

Nanoleaf HomeKit lights are already great for mood lighting and entertainment. Light “games” could just be a gimmick on their own, but I can definitely see a simple game of “Whack A Mole” or “PacMan” being a great party trick — especially with kids.

Personally, I really like Nanoleaf Light Panels. The triangular tiles cover more wall space and let you create designs that look a bit less 8-bit. I recommend Nanoleaf Canvas for most people though — especially over similar products.

The modular system is just as easy to use and the built-in support for music scenes and brightness control make it more polished — plus the touch-controlled games add to the entertainment.

Catch up on earlier HomeKit Weekly entries below:

Matter can travel to the future through black holes, predicts new theory

Two new papers say everything we knew about black holes was wrong.

Toddler nightlight/stay-in-bed device

Living with a toddler is the best thing. It really is. Seen through their eyes, everything you’re jaded about becomes new and exciting. Every piece of music is new. Frog and Toad are real people. Someone doesn’t care that you’re really, really bad at drawing, believing that you’re actually a kind of cross between Leonardo and Picasso; and you have a two-foot-tall excuse to sing Gaston at the top of your voice in public. The parents of toddlers are allowed into the ball pit at soft play. There’s lots of cake. The hugs and kisses are amazing.

frog and toad

However. If my experience here is anything to go by, you may also be so tired you’re walking into things a lot. It doesn’t matter. The hugs and kisses are, like I said, amazing. And there are things you can do to mitigate that tiredness. Enter the Pi.

stay focused

I’m lucky. My toddler sleeps through. But sometimes she has an…aggravating habit of early wakefulness. After 7am I’m golden. I can do 6.30 at a push. Any earlier than that, though, and I am dead-eyed and leather-visaged for the rest of the day. It’s not a good look. Enter equally new parent Cary Ciavolella, who has engineered a solution. This is a project so simple even the most sleep-deprived parent should be able to put it together, using Pimoroni parts you can easily buy online. Cary has thoughtfully made all the code available for you so you don’t have to do anything other than build the physical object.

Pi nightlight

Cary’s nightlight can produce a number of different sorts of white noise, and changes colour from red (YOU’RE MEANT TO BE ASLEEP, KID) through orange (you can play in your room) to green (it’s time to get up). Coloured lights are a sensible option: toddlers can’t read numbers, let alone a clock face. It’s all addressable via a website, which, if you’re feeling fancy, you can set up with a favicon on your phone’s home screen so it feels like an app.

White noise – I use a little box from Amazon which plays the sound of the sea – and red-spectrum nightlights have solid research behind them if you’re trying to soothe a little one to sleep. Once you cross over into blue light, you’ll stop the pineal gland from producing melatonin, which is why I hate the fan I bought for our bedroom with a burning, fiery passion. Some smart-alec thought that putting a giant blue led on the front to demonstrate that the fan was on was a smart idea, never mind the whirling blades which are obvious to at least three of the senses. (I have never tried tasting it.)

With this in mind, I’ve one tiny alteration to make to Cary’s setup: you can permanently disable the green LED on the Pi Zero itself so that the only lights visible are the Pimoroni Blinkt – namely the ones that your little one should be looking at to figure out whether it’s time to get up yet. Just add the following to the Zero’s /boot/config.txt and reboot.

# Disable the ACT LED on the Raspberry Pi.

A buried lake on Mars excited and baffled scientists

Liquid water under so much ice is a hard sell, and only one of two orbiters has detected it

8:21AM, DECEMBER 17, 2018
Mars south pole

HIDDEN DEPTHS  Layers in the ice near Mars’ south pole, shown here in a 2012 composite image from the European Space Agency’s Mars Express orbiter, could conceal a briny lake buried 1.5 kilometers below the surface.

Headlines touting the discovery of water on Mars — again! — are a long-standing punchline among planetary scientists. But a discovery this year was something very different. 

Unlike previous claims of water-bearing rocks or ephemeral streaks of brine, researchers reported in the Aug. 3 Science that they had found a wide lake of standing liquid near the Red Planet’s south pole, buried beneath 1.5 kilometers of ice (SN: 8/18/18, p. 6). The purported polar pool, spotted by an orbiting satellite, is the largest volume of liquid water ever claimed to currently exist on Mars, and has probably been around for a long time. Both of those features raise hopes that life could survive on Mars today.

But months after the announcement, the discovery remains controversial. First, it’s not clear how that water could remain liquid when the temperature at that icy depth should be about –68° Celsius. Even salts dissolved in the water would have a hard time melting ice that cold. “This is the main objection that has been raised,” says one of the lake’s discoverers, planetary scientist Roberto Orosei of the National Institute for Astrophysics in Bologna, Italy.

The other concern is that a second Mars orbiter, which should be able to detect such lakes, has seen nothing so far.

Orosei, however, thinks he has the answer to both puzzles: If Mars’ south polar ice cap has a texture like Styrofoam, he says, that could both insulate the lake and befuddle the other orbiter.

Blue lagoon

Ice-penetrating radar beamed down from the Mars Express orbiter revealed a hidden lake on Mars. The blue triangle outlined in black in the middle is the purported lake.


Orosei and colleagues spotted the lake after years of analyzing data from the European Space Agency’s Mars Express orbiter, which aims radar at the planet to see below its surface. As radar waves bounce off an interface between two materials, the brightness of the reflection can tell scientists what those materials are. Orosei’s group found a bright triangular reflection measuring about 20 kilometers across at Mars’ south pole. A lake of liquid water beneath the ice is the most likely explanation, Orosei says.

NASA’s Mars Reconnaissance Orbiter, which has also observed the south pole with radar, has seen no sign of the lake. “It’s a big mystery,” says Toronto-based planetary scientist Isaac Smith of the Planetary Science Institute, who works on the NASA mission. “We’d love to figure it out.”

Tiny pockets of air in the polar ice sheet might explain the conflicting radar results, Orosei suspects. If the ice is riddled with holes, they may scatter the Mars Reconnaissance Orbiter’s short-wavelength radar, like light filtering through a cloud. That scattering would hide the lake from the short-wavelength radar’s view. But Mars Express’ longer-wavelength radar could pass through the ice cleanly allowing it to reach and reflect off the lake.

The air in those holes would also help insulate lower layers of ice and raise the temperature there, or hold in heat from the planet’s interior more efficiently, similar to the way a Styrofoam cup keeps coffee hot.

“This is just a conjecture at the moment,” Orosei cautions.

Smith thinks porous, Styrofoam-like ice sounds plausible, but hard to explain. On Earth, ice normally packs tightly and becomes denser as it grows thicker. It’s hard to see how such a thick slab of ice on Mars would not do the same. Other orbital measurements suggest that Mars’ ice is even denser than regular water ice, which doesn’t leave much room for air holes.

But Mars’ south polar ice behaves differently than earthly ice in other ways too, Smith says. It doesn’t flow the way you would expect from tightly packed glaciers. Porous ice might explain why it flows differently, and more dust and other impurities in the ice could make up for the difference in density.

“It would be a big surprise,” Smith says. “But Mars is a unique place.”

If the ice is porous, there should be more insulated lakes hidden beneath the ice cap, Orosei says. The Mars Express team may have seen some hints of such lakes already, although it’s too early to be sure.

Finding additional lakes would be great news for the possibility of life there. If life took root in the past, it could still hang on in these long-lived subglacial lakes, like life does in similar lakes in Antarctica (SN: 9/20/14, p. 10).

“This means you would have a sort of Noah’s ark for life to exist today, if it ever developed on early Mars,” Orosei says. “The chances of finding extant life today would be much greater.”


R. Orosei et al. Radar evidence of subglacial liquid water on MarsScience. Vol. 361, August 3, 2018, p. 490. doi: 10.1126/science.aar7268.

Further Reading

L. Grossman. Mars (probably) has a lake of liquid waterScience News. Vol. 194, August 18, 2018, p. 6.

L. Grossman. What does Mars’ lake mean for the search for life on the Red Planet? Science News Online, July 27, 2018.

T. Sumner. Lake under Antarctic ice bursts with lifeScience News. Vol. 186, September 20, 2014, p. 10.

A Neuroscientist Explains Why Multitasking Screens Is So Terrible For Your Brain

16 DEC 2018

How many times have you sat down to watch TV or a movie, only to immediately shift your attention to your smartphone or tablet? Known as “media multitasking”, this phenomenon is so common that an estimated 178m US adults regularly use another device while watching TV.

main article imageWhile some might assume that frequently shifting your attention between different information streams is good brain training for improving memory and attention, studies have found the opposite to be true.

Media multitasking is when people engage with multiple devices or content at the same time. This might be using your smartphone while watching TV, or even listening to music and text messaging friends while playing a video game.

One recent study looked at the body of current research on media multitasking (consisting of 22 peer-reviewed research papers) and found that self-reported “heavy media multitaskers” performed worse on attention and working memory tests. Some even had structural brain differences.

The study found that “heavy” media multitaskers performed about 8-10% worse on sustained attention tests compared to “light” media multitaskers. These tests involved participants paying attention to a certain task (such as spotting a specific letter in a stream of other letters) for 20 minutes or more.

Researchers found that on these tests (and others) the ability to sustain attention was poorer for heavy multitaskers. These findings might explain why some people are heavy multitaskers.

If someone has a poor attention span, they may be likely to switch between activities quickly, instead of staying with just one.

Heavy media multitaskers were also found to perform worse than light media multitaskers on working memory tests. These involved memorising and remembering information (like a phone number) while performing another task (such as searching for a pen and piece of paper to write it down).

Complex working memory is closely linked with having better focus and being able to ignore distractions.

Brain scans of the participants also showed that an area of the brain known as the anterior cingulate cortex is smaller in heavy multitaskers. This area of the brain is involved in controlling attention. A smaller one may imply worse functioning and poorer attention.

But while researchers have confirmed that heavy media multitaskers have worse memory and attention, they are still uncertain about what causes heavy media multitasking.

Do heavy media multitaskers have worse attention because of their media multitasking? Or do they media multitask because they have poor attention?

It might also be an effect of general intelligencepersonality, or something else entirely that causes poor attention and increased media multitasking behaviours.

But the news isn’t all bad for heavy multitaskers. Curiously, this impairment might have some benefit. Research suggests that light media multitaskers are more likely to miss helpful information that isn’t related to the task they’re currently performing.

For example, a person may read with a radio playing in the background. When important breaking news is broadcast, a heavy media multitasker is actually more likely to pick it up than a light media multitasker.

So should you avoid media multitasking? Based on current research, the answer is probably yes. Multitasking usually causes poorer performance when doing two things at once, and puts more demands on the brain than doing one thing at a time.

This is because the human mind suffers from an “attentional bottleneck”, which only allows certain mental operations to occur one after another.

But if you’re wondering whether media multitasking will impair your attention capabilities, the answer is probably no. We don’t know yet whether heavy media multitasking is really the cause for lower performance on the tests.

The effects observed in controlled laboratory settings are also generally rather small and most likely negligible in normal everyday life.

Until we have more research, it’s probably too early to start panicking about the potential negative effects of media multitasking.The Conversation

André J. Szameitat, Reader in Cognitive Neuroscience, Brunel University London.

This article is republished from The Conversation under a Creative Commons license. Read the original article.