JON CARTWRIGHT – & THREE QUARKS EDITORIAL

A field guide to the quantum realm

New ScientistJon Cartwright8 April, 2023

The ancient Greeks speculated that it might be air, fire or water. A century ago, physicists felt sure it was the atom. Today, we believe that the deepest layer of reality is populated by a diverse cast of elementary particles, all governed by quantum theory.

From this invisible, infinitesimal realm, everything we see and experience emerges. It is a world full of wonder, yet it can be mystifying in its weirdness. Over the next 10 pages, Jon Cartwright presents a guide to its inhabitants and their strange behaviours – as well as some of the hypothetical particles that physicists still hope to discover.

We start with what we pretty much know for sure. Visible matter consists of atoms, and at the centre of atoms are protons and neutrons. But even these aren’t elementary particles, as detailed by the current “standard model” of particle physics, our leading description of reality on the tiniest scales. So we begin, deep down, with what matter is really made of.

ELECTRONS
Weighing in around 1800 times lighter than protons or neutrons, electrons add very little to the overall mass of atoms. Without the electron, however, we would scarcely be able to feel matter at all. That is because electrons have a negative charge and exist in an “orbit”, or cloud, surrounding atomic nuclei. When you touch something, the atoms in your fingertip aren’t directly butting up against the ones in an object. Instead, what you are feeling is the mutual repulsion between the negative electrons surrounding the atomic nuclei in your finger and those in the object, via the force of electromagnetism (see “Photons: Electromagnetism”).

The electron plays the lead role in almost all other aspects of everyday life, too. By and large, when atoms bind in solids, liquids and gases, it is through the transfer or sharing of electrons, to balance charge and make things stable. All chemical reactions – from photosynthesis to combustion, from decomposition to the subtle reactions involved in our sense of taste and smell – similarly boil down to electron rearrangement. They are also the vehicles of electricity: their fine manipulation in transistors, which control the flow of electrical current, is what makes computers and many other modern technologies possible. […]

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A brief history of the Standard Model

New ScientistJon Cartwright6 September, 2023

Our amazing picture of the particles and forces that make reality took decades of invention and experiment to piece together

LOOK closely enough and almost everything we know of in the universe boils down to a handful of elementary particles. These entities constitute individual threads of the scientific masterpiece that is the standard model of particle physics, our current best picture of matter and its workings.

Its roots lay in the quantum revolution early in the 20th century, where the classical, common-sense notion that everything is predictable was unceremoniously thrown out. By contrast, the development of the standard model was anything but a revolution. Instead, it was more like the gradual forming of a new order, constructed piece by piece by dozens of physicists across decades.

Many expected the new order to fail. But it didn’t. In fact, the standard model has survived every test we have thrown at it, including attempts to create new particles or to find new forces that it doesn’t predict (see “Six ways we could finally find new physics beyond the standard model“). So how, exactly, did physicists working throughout the 20th century come up with such an unbreakable framework? This is the story of the most successful theory we have ever devised. […]

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Tabletop universe

New ScientistJon Cartwright27 May, 2023

Physicists are conjuring crude models of the cosmos in glass tanks and tubes. Can these simulations reveal the secrets of space and time, asks Jon Cartwright

GERMAIN ROUSSEAUX owns what looks like a very long and very narrow fish tank, minus the fish. At the bottom, in the middle, is a plastic ramp. When he switches on the apparatus, waves sweep along the tank and pass over the ramp, speeding up as they do so. This, he says, is a black hole.

Well, not a black hole in the common sense. Not a star-gobbling pit in the fabric of space-time. Rousseaux’s experiment at the Institut Pprime in Poitiers, France, is a physical model of how the immense gravity of black holes can suck in waves – conventionally light waves, but in this case water waves – so they can’t escape.

It is what is known in the trade as a “gravity analogue”, and it is far from the only one. Over the past 15 years, researchers have created dozens of these tabletop models – despite the mutterings of many theorists, who are sceptical that such simple experiments can tell us anything about the universe’s most darkly mysterious objects.

Yet some researchers have begun to simulate more and more aspects of the universe, including even the entire infant cosmos. Now, some of them believe the models are giving us insights into the deepest nature of reality. There is even a suggestion that the speed of light, that hallowed constant of physics, might not be fixed after all. “Applying insights from these models would imply a radical shift in view,” says Rousseaux. But can we really rely on tanks of liquid to solve the mysteries of how the universe works?

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Instant power

New ScientistJon Cartwright7 September, 2022

Quantum batteries that recharge in a flash could accelerate the electric car revolution, says Jon Cartwright

THE battery, as US comedian Demetri Martin pointed out, is one technology that we personify. “Other things stop working or they break” he said “But batteries – they die.” The observation is keener than it may at first appear. So beholden are some of us to smartphones, tablets and other digital technology, that our lives pretty much go on hold when they run out of juice. Even if it is just 30 minutes, we are apt to mourn the time lost to recharging.

If that seems like a laughable reaction, there is a serious side to this when it comes to the batteries that power electric vehicles. The fact that it usually takes hours to charge them is a major stumbling block to decarbonising transport, which is among the biggest global emitters of greenhouse gases. For humanity’s sake, charging times need to be slashed. Yet, with the fundamentals of battery science the same as they were half a century ago, the prospect of a drastic improvement looks slim.

Slim, but not impossible. Now, quantum physics could ride to our rescue. By leveraging the strange behaviour of subatomic particles, a quantum battery could charge itself much faster than any conventional device. As a handy bonus, the bigger a quantum battery, the better it performs. Although the concept is in its infancy, a recent experimental demonstration and some theoretical advances suggest that a world of uninterrupted portable power isn’t so far-fetched. One day, dead batteries could spring back to life in an instant. […]

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Making sense of matter

New ScientistJon Cartwright4 August, 2021

For the first time, we are able to predict exotic new states of matter. It could lead to a tech revolution, says Jon Cartwright

THE tenets of physics can seem carved in stone. The speed of light is a constant. There are four fundamental forces. Theoretically, rules like these are open to revision. But new contenders had better come with a chisel and a very big hammer.

You would be forgiven for thinking this confidence also applies to something as fundamental as the different states of matter. As we learned in school, there are three of them: solid, liquid, gas. Right?

Actually, these are only the start. We now know of all sorts of exotic states, from superconductors to Bose-Einstein condensates, quantum spin liquids to topological insulators. The sheer number is as bewildering as their names. Strangely, no one can give you a definitive list: there could be as few as four of them or perhaps thousands.

Sorting this mess out isn’t just a matter of satisfying our curiosity. If we can pin down exactly what constitutes a state of matter, we should be better able to predict and discover new ones. That would not only have great technological benefits, but it could also give us fresh ways to probe the nature of reality.

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It’s topology, naturally

Physics WorldJon Cartwright5 June, 2021

One of the hottest topics in solid-state physics is having a fluid makeover. As Jon Cartwright reports, the consequences of topological behaviours in fluid dynamics could be far-reaching for our understanding of the natural world and other complex systems, such as fusion tokamaks

ASK a solid-state physicist to name the biggest discovery in the field over the past 50 years, and chances are the answer – if not high-temperature superconductivity – will be topological materials. These are materials in which bulk properties determine special behaviour along the surface or an edge, and they have profoundly changed the study of electrons in solids – as recognized by three Nobel prizes. Their earliest incarnations in physics have created a new standard for electrical resistance, and provided an independent means to determine the fine-structure constant, ?, in quantum electrodynamics. These materials are also expected to bring great advances to information processing, resulting from topological electron behaviour in graphene, or the harnessing of topological qubits in quantum computing. Even exotic entities such as magnetic monopoles and Majorana particles, once a province of particle physics, have become the subject of solid-state topological study.

But now topology is going beyond the solid state. In the past few years, physicists have begun to realize that it could have a major role in fluid dynamics – the Earth’s oceans, for example, or plasmas, or the biological cells in fluid-like “active” matter. The research promises to provide a clear window through which to study what can otherwise be very murky areas of science. More importantly, it brings an entirely new area of mathematics to our understanding of the natural world; as well as to complex artificial systems of huge practical importance, namely fusion reactors. “Topology gives you a quick, direct way to see whether waves [in certain systems] exist,” says theorist Brad Marston of Brown University in Rhode Island. “Once you work through the logic, answers can come very simply.” […]

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Garden hoses help explain why mammals can maintain stiff erections

New ScientistJon Cartwright23 March, 2021

Mammals are able to maintain stiff erections because their penises have a rare form of internal reinforcement. Now, a discovery inspired by playing with a garden hose means we finally understand the extent of the benefits this offers.

“It was a pandemic lockdown issue,” says Peter Palffy-Muhoray, a physicist at Kent State University in Ohio who normally studies liquid crystals. “While out in the back yard, we noticed the funny undulations of a hose, and wondered about it. Then we stumbled on the amazing biological parallel. Of course, how can one resist a puzzle involving penises?”

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The next dimension

New ScientistJon Cartwright14 October, 2020

We only ever experience three spatial dimensions, but quantum lab experiments suggest a whole new side to reality – weird particle apparitions included

YOU are running through an open field with the wind in your hair. Or you are diving into the ocean, feeling the cool water surround you. At moments like these we feel free, liberated. Few of us stop to consider the truth – that we are trapped in an invisible prison.

Up-down, left-right, forward-back: these are the three dimensions in which we eat and breathe, make friends and grow old. As prisons go, it could be worse. Then again, we have never known anything else. Despite some imaginary claims to the contrary, no one has ever really experienced a higher dimension.

But now, in some of the world’s most sophisticated labs, we are building our own synthetic extra dimensions. The concept is so far removed from our experience that it is hard to imagine what they could be like. We have, however, already seen the ghostly effects of four-dimensional space touch on our own and wired up electric circuits with an extra dimension. It is unlikely to stop there. Now we have got the hang of it, there is talk of creating five, six or even more dimensions, and even suggestions that exotica such as new particles might lurk in the extra-dimensional wilderness.

This is a frontier that we are barred from exploring directly. We are forced instead to look for the subtle imprints that extra dimensions make on the three dimensions we are confined to. Even so, we could be about to extend the boundaries of reality in ways that come close to the limits of our descriptive powers. […]

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The potential of far-ultraviolet light for the next pandemic

Physics WorldJon Cartwright19 May, 2020

According to the physicist Charlie Ironside, our ability to deal with future deadly pandemics could be better – if we look to the far-ultraviolet. Jon Cartwright reports on a call to arms for the LED industry

Imagine a world where people travel as they wish. They shake hands when they make new acquaintances, embrace when they greet close friends and elderly relatives. They do not bother to laboriously disinfect their work surfaces, or wash their hands once they have dealt with the post. They go shopping as they please and find no shortage of provisions. They work in offices, laboratories, shops, restaurants and building sites. They conduct meetings in person, and think nothing of it when they jet off to their favourite holiday destination. They do all this because a COVID-19 vaccine has been developed, rolled out and administered to the entire populace, making all the chaos of 2020 a distant memory. Everything is back to normal.

This is the ending to the coronavirus pandemic we are all hoping for, and, give or take some of the details, there is no reason why it is not possible. But even in this optimistic scenario, there is a deep fear among scientists and policy makers: what happens next time? For if there is one lesson that COVID-19 has taught us, it is that our modern lifestyles are fatally ill-suited to the emergence of novel viruses – and novel viruses there will always be. Any drugs and vaccines we develop for COVID-19 will be ineffectual against the next viral pandemic, which may well consist of a different family of virus altogether. Indeed, unless anything in our approach to pandemics changes, the next one will entail another psychologically and economically crippling lockdown while scientists find a cure – however long that takes.

Yet according to one scientist, there is something we can do differently next time. Charlie Ironside of Curtin University in Perth, Australia, is not a virologist or an epidemiologist but a physicist – one who has spent 30 years specializing in semiconductor optoelectronics. His solution: far-ultraviolet light-emitting diodes (far-UV LEDs). […]

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Into the antiverse

New ScientistJon Cartwright8 April, 2020

Strange particles observed by an experiment in Antarctica could be evidence of an alternative reality where everything is upside down

IN THE Antarctic, things happen at a glacial pace. Just ask Peter Gorham. For a month at a time, he and his colleagues would watch a giant balloon carrying a collection of antennas float high above the ice, scanning over a million square kilometres of the frozen landscape for evidence of high-energy particles arriving from space.

When the experiment returned to the ground after its first flight, it had nothing to show for itself, bar the odd flash of background noise. It was the same story after the second flight more than a year later.

While the balloon was in the sky for the third time, the researchers decided to go over the past data again, particularly those signals dismissed as noise. It was lucky they did. Examined more carefully, one signal seemed to be the signature of a high-energy particle. But it wasn’t what they were looking for. Moreover, it seemed impossible. Rather than bearing down from above, this particle was exploding out of the ground.

That strange finding was made in 2016. Since then, all sorts of suggestions rooted in known physics have been put forward to account for the perplexing signal, and all have been ruled out. What’s left is shocking in its implications. Explaining this signal requires the existence of a topsy-turvy universe created in the same big bang as our own and existing in parallel with it. In this mirror world, positive is negative, left is right and time runs backwards. It is perhaps the most mind-melting idea ever to have emerged from the Antarctic ice – but it might just be true. […]

The rest of this article is available here.