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Why we need gender equality in big science

Investments in “big-science” projects, whether it’s the next particle collider or a new synchrotron, are often justified in terms of the benefits for science, such as the discovery of a new particle or the opening of a new vista on the cosmos. The positive impact of large facilities on society and the economy are often cited too, such as spin-off technologies in medical physics. Gender equality, however, is rarely acknowledged as a necessary objective when building these multi-billion-euro facilities or investing in the research required to develop them. That lack of focus on gender equality is something that I believe must change.

The lack of gender-based targets for big science is laid bare in a tool created as part of the European Union’s Horizon 2020 funding programme. Produced by the Research Infrastructure Impact Assessment Pathways project, it assesses the impact of research infrastructures on the economy and society via 122 “impact indicators” in four areas: human resources; policy; society; and economy and innovation. But only one indicator – contribution to gender balance in society – gives any mention to gender equality.

Yet improvements can be made when it comes to supporting female scientists in big science. Take the EU-wide ATTRACT project, which funds the development of breakthrough technologies via proof-of-concept projects. It is led by large research organizations such as the CERN particle-physics laboratory near Geneva, the X-ray Free Electron Laser in Hamburg, Germany, and the European Southern Observatory. Between 2018 and 2020, ATTRACT supported 170 projects, half of which focused on health, environment and biological and related sciences. However, only 11% of the funded ATTRACT projects had a woman as the principal investigator, even though women receive almost half of doctoral degrees in those areas.

Such numbers tell us we have a long way to go. After all, big-science facilities receive significant amounts of public money and employ thousands of people in different professional roles. We need to promote big science as a career destination not only for science graduates but also those in law, management and policy. Monitoring gender balance among the staff and users of research infrastructures and the members of big-science projects is crucial to ensuring that women graduates, who outnumber men in Europe, see big science as a place where they can thrive professionally.

In that regard, there have been some positive developments. The EU’s €96bn Horizon Europe programme – the successor to Horizon 2020 – now requires that all benefiting organizations, many of which participate in big-science projects, have a gender equality plan. Several industry sectors are also doing lots to integrate equality, diversity and inclusion into human resources practices to attract talent.

Tapping into the talent pool

But more needs to be done. That’s why since 2020 the Women in Big Science Business Forum (WBSBF) has been promoting gender equality as part of the Big Science Business Forum (BSBF). The WBSBF was set up by a group of people at Fusion for Energy, which manages the EU’s contribution to the ITER fusion experiment being built in France. The BSBF itself is trying to advance gender equality across research infrastructures, universities and supplier companies. For instance, since research infrastructures distribute billions of euros of public money in procurement and investment, they can adopt procurement processes that question the supplier’s compliance with gender-equality legislation and ask for examples of efforts they have made to recruit and retain women.

“Gender budgeting” is a tool that big-science projects can also use to assess how their budget decisions impact gender equality. That could mean eliminating the gender pay gap, making provisions for equal parental leave or ensuring that research grants are the same for projects whether led by women or men. Budgets could also be earmarked to help staff achieve a work–life balance. I think it’s important as well that we improve training in gender equality and that we “gender proof” recruitment by identifying and removing potential biases to assessment criteria that could favour men. Big-science projects can also make use of the European Charter & Code for Researchers, which includes a dozen gender-equality indicators as part of the EU initiative “human resources strategy for researchers”.

At the BSBF meeting in Granada in 2022, the WBSBF launched a recognition award to acknowledge, celebrate and promote successful measures taken by big-science organizations to increase the proportion of women among their staff and users of research infrastructures. There are three categories: “advances in organizational culture”; “collaborative partnerships”; and “societal impact”. Some 13 organizations applied for an award in 2022, with organizations such as XFEL and CERN being recognized.

The WBSBF is building on that progress at this year’s BSBF event in Trieste, Italy, in October with activities on socially responsible procurement, gender balance in work policies, and the socioeconomic impact of investment in big science. There will also be a live-streamed round-table session with leaders from big science. At Trieste, we’ll also be introducing a WBSBF trainee scheme, which will place three to five students or recent graduates on in-house trainee programmes run by labs, companies or intergovernmental bodies taking part in BSBF. Those roles don’t have to be scientific or technical, but could also be in, say, legal, communication or human resources.

Big science needs more women and I hope these initiatives will help to turn the tide. The talent pool for women is already there and big science must get better at tapping into it, not only for the discoveries that lie ahead but also for building a better relationship with society.

The WBSBF group comprises Francesca Fantini, Aris Apollonatos, Romina Bemelmans, Silvia Bernal Blanco, Carmen Casteras Roman, Ana Belen Del Cerro Gordo, Pilar Rosado, Maria Cristina Sordilli and Nikolaj Zangenberg
To find out more about the recognition award and the WBSBF trainee scheme, e-mail wbsbf@f4e.europa.eu

The eyes have it: how to spot the difference between a deepfake portrait and a real picture

How do you spot a deepfake image of a person? The answer might be to look into their eyes.

That is according to astronomers at the University of Hull in the UK who say that AI-generated pictures can be unmasked by analyzing human eyes in the same way that astronomers study images of galaxies.

The team analysed reflections of light on the eyeballs of people in real and AI-generated images.

They then employed methods typically used in astronomy to quantify the morphological features of the reflections in both eyes.

“To measure the shapes of galaxies, we analyse whether they’re centrally compact, whether they’re symmetric, and how smooth they are,” notes Hull astrophysicist Kevin Pimbblet. “We analyse the light distribution.”

They found that fake images often lacked consistency in the reflections between each eye, whereas real images generally show the same reflections in both eyes.

Yet Pimbblet warns that the technique is “not a silver bullet” when it comes to detecting fake images.

“There are false positives and false negatives [so] it’s not going to get everything,” he adds. “But this method provides us with a basis, a plan of attack, in the arms race to detect deepfakes.”

The work was presented this week at the Royal Astronomical Society’s National Astronomy Meeting in Hull.

Diamond dust for MRI, 4D printing creates advanced devices

New and exciting technologies feature in this episode of the Physics World Weekly podcast.

Our first guest is the neuroscientist and physicist Jelena Lazovic Zinnanti, who recalls how she discovered (by accident) that nanometre-sized diamond particles shine brightly in magnetic resonance imaging (MRI) experiments. Based at Max Planck Institute for Intelligent Systems, she explains how this diamond dust could someday replace gadolinium as a contrast agent in MRI medical scans.

This episode also features an interview with Mahdi Bodaghi of Nottingham Trent University, who is an expert in 4D and 3D printing. He talks about the engineering principles that guide 4D printing and how the technique can be used in a wide range of applications including the treatment of coronary heart disease and the design of flatpack furniture. Bodaghi also explains how 3D printing can be used to create self-healing asphalt.

Mahdi Bodaghi is on the editorial board of the journal Smart Materials and Structures. It is published by IOP Publishing, which also brings you Physics World.

Robotic radiotherapy could ease treatment for eye disease

A single dose of radiation can reduce the number of eye injections needed to treat patients with neovascular age-related macular degeneration (AMD). That’s the conclusion of a UK-based clinical trial of more than 400 patients with the debilitating eye disease.

AMD affects 8% of adults globally, and is a leading cause of central blindness in people over 60 in developed nations. Neovascular (or wet) AMD, the most advanced and aggressive form of the disease, causes new blood vessels to grow into the macula, the light-sensing layer of cells inside the back of the eye. Leakage of blood and fluid from these abnormal vessels can lead to a rapid, permanent and severe loss of sight.

The condition is treated with injections of drugs into the eye, with most people requiring an injection every 1–3 months to effectively control the disease. The drugs inhibit vascular endothelial growth factor (VEGF), a key driver of vascular leakage and proliferation. Reporting their findings in The Lancet, the investigators suggest that SRT could eliminate 1.8 million anti-VEGF injections per year globally across all high-income countries.

STAR treatment

The STAR (stereotactic radiotherapy for wet AMD) study, led by Timothy Jackson of King’s College London, is a double-blinded trial that enrolled patients with previously treated chronic active neovascular AMD from 30 hospitals in the UK. All participants received the robotic treatment, with or without delivery of 16 Gy of radiation, at one of three UK treatment centres.

The team used a robotically controlled SRT system that delivers three highly collimated 5.33 Gy radiation beams, targeted to avoid lens irradiation and overlapping at the macula. To stabilize the eye being treated, a suction-coupled contact lens was secured to the cornea and connected to a positioning gimble with infrared reflectors. The SRT device tracked the reflectors, stopping the treatment if the eye moved out of position.

The researchers randomly allocated 274 patients to receive the 16 Gy SRT treatment and 137 to receive identical sham treatment without radiation. Immediately afterwards, all patients received a standard dose of the anti-VEGF drug ranibizumab injected into the eye.

After radiotherapy, participants visited their recruiting hospital for follow-up exams every four weeks up to the 96-week primary endpoint. During these review sessions, patients received an intraocular injection of ranibizumab each time they needed retreatment. The researchers are continuing assessments at three and four years to determine the safety and long-term efficacy of this approach.

The final study analysis included 241 participants in the 16 Gy SRT group and 118 participants in the sham group, with total of 409 patients treated and forming the safety population. The findings are encouraging: patients who received SRT required a mean of 10.7 injections after 96 weeks, compared with 13.3 injections for the conventional drug-only group.

Reducing the burden of anti-VEGF treatment would be highly beneficial for both patients and hospitals. Preliminary analyses suggest that the cost of the SRT treatment may be more than offset by the reduction in injections. The authors plan to prepare a detailed cost evaluation.

Vision outcome for both cohorts was comparable. While the sham group had slightly less worsening of best corrected visual acuity at two years, there was no statistical difference between the two. The systemic safety was also similar in the two groups, with similar rates of adverse events. Evaluation using multimodal imaging determined that 35% of the SRT-treated participants and 12% of the sham group had retinal microvascular abnormalities.

The study outcome supports the findings of a similar phase II clinical trial, INTREPID, whose results were published in 2020. The INTREPID study of 230 randomized patients showed that a single radiation dose of 16 or 24 Gy administered by SRT reduced injections by 29% for the ensuing 12 months, compared with the control group.

Jackson tells Physics World that the researchers are currently analysing data from patients reporting for their three- and four-year anniversary examinations. The data suggest increasing benefit with respect to injection frequency over time. The investigators also note that the benefits of SRT may be eroded by the introduction of newer intravitreal drugs such as faricimab, or higher doses of existing anti-VEGF drugs, which have longer dosing intervals than ranibizumab.

Adaptive optics pioneers win Rank Prize for retinal imaging breakthroughs

Writing in an accompany commentary in The Lancet, Gui-shuang Ying and Brian VanderBeek of the University of Pennsylvania Perelman School of Medicine state: “The STAR study has indicated a potential alternative treatment paradigm that appears to significantly reduce treatment burden without impacting visual acuity outcomes over two years, but additional gaps in knowledge need to be addressed before the widespread adoption of this therapy.”

They add: “If the reduction in anti-VEGF injection rate, non-inferior visual acuity results and acceptable safe profile of SRT remain through future studies, the STAR study will be a foundational piece in advancing a promising adjunctive therapy forward. Patients eagerly await the day when the injection burden is reduced, and SRT might well be a path to getting there.”

Speedy stars point to intermediate-mass black hole in globular cluster

**Hubble zooms in** A wide view of Omega Centauri reveals a dense collection of stars (left). The middle image shows a closer view of the central region of the cluster. The image on the right shows the location of the IMBH candidate in the cluster. (Courtesy: ESA/Hubble & NASA, M Häberle (MPIA))

The best evidence yet for an intermediate-mass black hole has been claimed by an international team of astronomers. Maximillian Häberle at the Max Planck Institute for Astronomy in Heidelberg and colleagues saw the gravitational effects of the black hole in long-term observations of the stellar cluster Omega Centauri. They predict that similarly-sized black holes could exist at the centres of other large, dense stellar clusters – which could explain why so few of them have been discovered so far.

Black holes are small and extraordinarily dense regions of space with huge gravitational fields that not even light can escape. Astronomers know of many stellar-mass black holes that weigh-in under about 100 solar masses. They are also are aware of supermassive black holes, which have 100,000s to billions of solar masses and reside at the centres of galaxies.

However, researchers know very little about the existence (or otherwise) of intermediate-mass black holes (IMBHs) in the 100–100,000 solar mass range. While candidate IMBHs have been spotted, no definite discoveries have been made. This raises questions about how supermassive black holes were able to form early in the history of the universe.`

Seeding supermassive growth

“One potential pathway for the formation of these early supermassive black holes is by the merger of intermediate mass ‘seed’ black holes,” explains Häberle. “However, the exact mass and frequency of these seeds is still unknown. If we study IMBHs in the present day, local, universe we will be able to differentiate between different seeding mechanisms.”

Häberle’s team examined the motions of stars within the globular cluster Omega Centauri, located around 17,000 light–years from Earth. Containing roughly 10 million stars, the cluster is widely believed to be the core of an ancient dwarf galaxy that was swallowed by the Milky Way. This would make it a prime target in the ongoing hunt for an IMBH within our own galaxy.

Häberle’s team analysed a series of images of Omega Centauri taken by the Hubble Space Telescope across a 20 years. By comparing the relative positions of the cluster’s stars in successive images, they identified stars that were moving faster than expected. Accelerated motion would be strong evidence that an IMBH is lurking somewhere in the cluster.

“This approach is not new, but we combined improved data reduction techniques with a much larger dataset, containing more than 500 individual images taken with the Hubble Space Telescope,” Häberle explains. “Therefore, our new catalogue is several times larger and more precise than all previous efforts.”

While some previous studies have presented evidence of an IMBH at the centre of Omega Centauri, the gravitational influence of unseen stellar-mass black holes could not be ruled out.

Seven speedy stars

Häberle’s team identified a total of seven stars at the very centre of Omega Centauri that appear to be moving much faster than the cluster’s escape velocity. Without some immense gravitational intervention, the researchers calculated that each of these stars would have left the centre of the cluster in less than 1000 years – a small blip on astronomical timescales – before escaping the cluster entirely.

“The best explanation why these stars are still around in the centre of the cluster is that a massive object is gravitationally pulling on them and preventing their escape,” Häberle claims. “The only object that can be massive enough is an intermediate-mass black hole with at least 8200 solar masses.”

The study makes Omega Centauri the best candidate in the Milky Way for having a IMBH. If confirmed, the IMBH will be the most massive black hole in the Milky Way after Sagittarius A* – the SMBH residing at our galaxy’s centre.

“To draw further conclusions and gain a statistical sample, we will now need to extend this research to other massive star clusters, where there might be still some hidden black holes,” Häberle says. The astronomers now hope that similar observations could soon be made using instruments including the Multi Unit Spectroscopic Explorer at the Very Large Telescope, and the James Webb Space Telescope’s Near-IR Spectrograph.

The research is described in Nature.

NASA cancels delay-hit $450m VIPER lunar prospector

NASA has cancelled a major Moon mission despite spending almost half a billion dollars on it. The Volatiles Investigating Polar Exploration Rover (VIPER) project was originally planned to launch late last year, but in 2022 NASA delayed it until late 2024 with further issues putting the launch date back until 2025. NASA now plans to disassemble VIPER and reuse the craft’s instruments and components on future Moon missions.

VIPER, about the size of a golf cart, would have prospected the lunar south pole for water ice in the soil with the aim of creating resource maps for future missions to the Moon. The craft would have spent 100 days roaming tens of kilometres where it would have used a neutron spectrometer to detect water molecules below the lunar surface. Another component of the mission was to use a drill to dig up the soil and determining the composition and concentration of the material via two other spectrometers.

NASA had already spent $450m on VIPER and the craft was currently undergoing testing. NASA says it will save about $85m by cancelling the mission while continuing with it would have threatened the “cancellation or disruption” of other Commercial Lunar Payload Services (CLPS) missions. The CLPS involves NASA working with US companies to build and launch lunar missions.

NASA will now “pursue alternative methods” to accomplish some of VIPER’s goals. The Polar Resources Ice Mining Experiment-1 (PRIME-1), for example, is scheduled to land at the south pole later this year aboard the lunar lander IM-2 built by Intuitive Machines as part of the CLPS programme. PRIME-1 will drill into the Moon’s surface where it lands and use a mass spectrometer to measure ice samples.

“We are committed to studying and exploring the Moon for the benefit of humanity through the CLPS program,” notes Nicola Fox, associate administrator for NASA’s Science Mission Directorate. “The agency has an array of missions planned to look for ice and other resources on the Moon over the next five years. Our path forward will make maximum use of the technology and work that went into VIPER, while preserving critical funds to support our robust lunar portfolio.”

Phil Metzger, director of the Stephen W. Hawking Center for Microgravity Research and Education at the University of Central Florida, said on X that the cancellation is a “bad mistake” and the mission would have been “revolutionary”. “VIPER was going to be an important step towards answering the question ‘are we alone in the cosmos?’” he says. “Other missions don’t replace what is lost here.”

Fox says NASA has already notified Congress of the decision, but Metzger now wants Congress to find the money to continue the mission. “[The cancellation] will be harmful to sustainability in space exploration, to geopolitical challenges in space, and to the most important, science,” he adds.

Industrial cryogenics and nanopositioning: into the fast-lane for quantum innovation

The nascent quantum technology supply chain has reached an inflection point as companies large and small – among them household names like Google, Microsoft and IBM as well as a new wave of ambitious start-up ventures – shift gears to translate their applied research endeavours into at-scale commercial opportunities in quantum computing, quantum communications and quantum metrology. At the heart of this emerging quantum ecosystem is attocube, a German manufacturer of specialist nanotechnology solutions for research and industry, which is aligning its product development roadmap to deliver the R&D and manufacturing tools needed to support the scale-up and commercialization of next-generation quantum technologies.

“We are facilitators of cutting-edge quantum R&D and technology innovation,” explains Khaled Karraï, co-founder and scientific director at attocube. That starts and ends, of course, with a granular understanding of the customers’ evolving requirements – not least when it comes to navigating the complex transition from research lab to manufacturing and, ultimately, long-term commercial impact. “Quantum is in our DNA at attocube, so we are extremely well positioned to service the needs of the quantum supply chain,” argues Karraï. “After all,” he adds, “we have worked hand-in-hand with quantum scientists in the academic world for the past 30 years. Many of those pioneering researchers are now in senior R&D and engineering positions in industry – and they’re coming to us for the enabling technologies they’ll need for the next stage on the quantum roadmap.”

Multiphysics innovation

By extension, the supporting product portfolio at attocube covers a lot of bases, including compact and low-vibration closed-cycle cryostats (with low-heat-generation compressors) and precision-motion components (such as nanopositioners and displacement-measuring interferometers) to align, operate and test advanced quantum components/subsystems. Downstream, those attocube products are put to work across a range of operating conditions – from ambient to ultralow temperatures, from low to ultrahigh vacuum, as well as within tightly constrained magnetic fields – to maintain the delicate quantum states and processes – think single-photon sources, trapped ions or superconducting or photonic qubits – within the core building blocks of quantum computing systems and quantum communication networks.

“Low-temperature nanopositioning and low-vibration cryogenics are among our core competencies at attocube,” notes Karraï. Equally important is what he calls a “multiphysics and multiengineering mindset” to ensure an integrated approach to product design and engineering. “Take position sensing at the nanoscale,” says Karraï. “This is a tricky enough proposition at room temperature, but it requires all sorts of innovative thinking when you throw in additional operating constraints like cryogenic temperatures, high vacuum and the need for miniaturization.”

Putting the focus on translation

Meanwhile, as quantum technology companies eye sustainable commercial opportunities over the near and medium term, the focus must necessarily shift to “productization” and hard-and-fast industrial metrics like scalability, reliability, manufacturability, robustness and cost:performance. Along that same coordinate lies a consideration of the operational running costs associated with first-generation quantum systems. A case in point: the energy-efficiency of the quantum repeaters that will be required every 100 km or so to boost optical signals within the quantum communication network – and, ultimately, across the quantum Internet.

Khaled Karraï, Attocube — **Khaled Karraï** “Quantum is in our DNA at attocube.” (Courtesy: attocube)

“Take a scenario where you want to cool an optical detector in a quantum repeater to, say, 2 K,” explains Karraï. “Today, you have to put 3 kW of energy in to generate something like 20 mW of cooling power. Now imagine that imbalance inside every quantum repeater within the long-haul fibre-optic network – the planet will be glowing.”

The answer, he believes, is the recently launched attoCMC, a compact and rack-mountable cryostat for in-field deployment (see “Working together to realize quantum advantage”, below). “With the attoCMC, we are delivering an order-of-magnitude reduction in energy consumption for the cryogenic subsystem,” claims Karraï. “This represents a step-change in energy-efficiency for quantum technology companies, giving them access to enhanced cooling capabilities for their distributed quantum computing and networking systems.”

Better together

Notwithstanding an over-arching emphasis on platform technologies that “unlock the creativity, ingenuity and imagination of our end-users”, Karraï highlights another key differentiator of the attocube working model – specifically, a vendor–customer relationship that moves beyond the transactional into the realm of collaborative R&D and co-development.

attoCMC cryostat — **Cool stuff** attocube’s attoCMC, a compact and rack-mountable cryostat for in-field deployment, provides a core building block in Quandela’s stand-alone quantum light source Prometheus. (Courtesy: Quandela)

It helps, in this regard, that many quantum technology companies have spun out from academia, subsequently recruiting specialists in industrialization and scale-up from other, more established tech sectors. “As a specialist equipment provider,” notes Karraï, “we need to be able to talk on a couple of levels with these customers – engaging their scientists and engineers on the one hand as well as the new breed of manufacturing specialists who want ready-made cryogenic or nanopositioning solutions built to their custom specification.”

The secret of success, argues Karraï, lies in an open, honest dialogue upfront between equipment supplier and customer. “It’s that informed conversation around technical requirements that’s so valuable at the initiation point,” he concludes. “Many of our product engineers have PhDs in quantum science and engineering, so are the best anchor-point for that dialogue around requirements-gathering. From here, our industrial customers quickly realize they can learn an awful lot by tapping into our collective domain knowledge in quantum technologies.”

Working together to realize quantum advantage

Quandela is a European start-up company that aims to accelerate the industrial and commercial roll-out of photonic quantum computing technologies. The Quandela development programme spans on-premises quantum computing systems (for deployment in data centres and supercomputing facilities); Quandela Cloud, a “quantum computing as a service” offering; and co-development (with industry partners) of quantum software for diverse use-cases in sectors like logistics, automotive, pharmaceuticals and finance. Here Niccolo Somaschi, CEO of Quandela, tells Physics World about his team’s strategic technology relationship with attocube.

What makes attocube a preferred supplier for Quandela?

Niccolo Somaschi, Quandela — Niccolo Somaschi “attocube is a key partner for both Quandela’s research activities and for the deployment of its industry-grade quantum computing solutions.” (Courtesy: Quandela)

It’s very simple: attocube prioritizes engineering excellence across a specialist product offering that guarantees bulletproof reliability for academic and industrial customers alike. Equally important, the attocube product development team listens to the market and, by extension, is ideally positioned to deliver industry-ready cryogenic and nanopositioning solutions that will enable quantum computing and quantum networking technologies to be deployed at-scale. It’s a visionary approach to product innovation.

How important is attocube’s long track-record of working with quantum researchers in academia?

Like attocube, Quandela was originally formed on the back of university research – in our case, translating academic quantum science and proof-of-concept R&D into industrial outputs and commercial growth. Quandela scientists and engineers are also long-time collaborators with attocube, relying on the company’s closed-cycle cryostats – specifically, the attoDRY800 and the attoDRY1000 – to support our previous academic research efforts. Today, seven years after its launch, Quandela is still a research-intensive company. As such, attocube remains a core technology partner, delivering the advanced research tools we need in the R&D lab, while working with us to navigate the transition to industry-grade solutions for the quantum supply chain.

How are attocube products supporting the Quandela development programme?

A case in point is the attoCMC, a new compact and rack-mountable cryostat system (with a base temperature of 2.3 K). Quandela saw the need for a cryogenic solution like the attoCMC even before its conception, so we were pleased to be among the first customers to evaluate early-stage prototypes. The attoCMC is now integrated as a core building block in Prometheus, our stand-alone single-photon source that’s designed to take quantum computing, quantum communications and quantum metrology applications out of the lab and into the field. Put simply, Prometheus delivers high-quality photonic qubits – on demand, deterministic, indistinguishable – at unprecedented rates, giving academic and industry users access to single photons at the push of a button.

Why North America has a ‘tornado alley’ and South America doesn’t

My home state of Kansas is famous for being very flat and having lots of tornadoes, so when I read that scientists in nearby Indiana have found a connection between flatness and tornado risk, I was intrigued.

Turns out, it’s not Kansas’ own flatness that’s to blame. Instead, scientists at Purdue University say that its exciting weather is due to the flat surface of the Gulf of Mexico. Together with other geographic factors, they argue, the ocean’s smoothness is what turns Kansas and neighbouring states into an ideal setting for films like the 1996 summer blockbuster Twister and its just-released sequel Twisters.

The scientists’ argument begins with a piece of conventional wisdom. The “tornado alley” of the North American Great Plains is commonly attributed to two geographic features: the Rocky Mountains to the west and the Gulf of Mexico and the Caribbean Sea to the south. When trade winds hit the east slope of this north–south mountain range, they turn northward and increase in speed while developing what meteorologists call “anticyclonic shear vorticity” – a fancy way of saying that the air starts to rotate counterclockwise. At the same time, southerly winds from the tropical Gulf pump warm, moist air into the lowest layer of the atmosphere. Together, these phenomena create conditions that favour severe thunderstorms and the tornadoes they spawn.

There’s just one problem with this story. The central region of South America (Uruguay and parts of Argentina, Paraguay and southern Brazil) is also next to a prominent north–south mountain range: the Andes. It also has a ready source of warm, moist air: the Amazon basin. And it also experiences a lot of severe thunderstorms – more thunderstorms, in fact, than central North America, with thunderclouds that extend further into the atmosphere. But tornadoes are much less common there, and the conventional wisdom can’t explain why.

An extra factor

In their study, which is published in PNAS, Purdue’s Dan Chavas and his then-PhD student Funing Li, together with colleagues at the US National Center for Atmospheric Research, Stony Brook University, and Colorado State University, sought an explanation in a previously overlooked difference between North and South America. While the surface of the Gulf of Mexico and Caribbean Sea is smooth, they noted, the similarly warm-and-moist Amazon basin is heavily forested and contains terrain such as plateaus and highlands. Might this roughness explain the absence of a South American tornado alley?

Photo of Dan Chavas in front of trees and flowers — Extreme weather expert: Dan Chavas studies both the climate science that creates the conditions for severe weather and the physics of the weather itself, including hurricanes, severe thunderstorms and tornadoes. (Courtesy: Purdue University/Greta Ball)

To test this hypothesis, the scientists performed experiments using a global climate model. In the first experiment, they flattened a computerized version of the Amazon basin to ocean-like smoothness and modelled the resulting tornado potential in central South America. In the second experiment, they did the opposite, filling in the digital Gulf of Mexico and observing how this affected tornado potential in central North America.

The results were striking. The smoothed-out version of South America experienced around twice as many tornadoes as the real-world version. Northeastern Argentina was particularly hard-hit. Conversely, a filled-in Gulf in the model version of North America reduced the number of tornadoes by up to 41%, with the biggest drops seen in the Great Plains and the southeastern US.

As a solution to Kansas’ tornado problem, this finding isn’t terribly useful. Human geoengineers are not going to start filling in the Gulf of Mexico any time soon, and the natural processes that might do it would be cataclysmic. (Let’s just say that a few extra twisters would be the least of our problems.) But the research does have some practical implications. Rampant deforestation is making the Amazon basin smoother. Forest regrowth is making the eastern US slightly rougher. According to the researchers, such changes could affect tornado frequency, though the exact nature of the effect is hard to predict.

“An important question is how terrain and land cover may alter the response of tornadoes in the future, as climate change may shift the large-scale atmospheric circulation and the geographic patterns of severe thunderstorm and tornado activity that it produces,” they write. “We hope our study motivates future research exploring those additional factors.”

Aperiodicity: the dance event bringing non-repeating patterns to life

We all like order in our lives (well, I do at least) but things rarely operate that way. In fact, the world is full of “aperiodic” order – patterns that aren’t totally repetitive but not completely random either.

Aperiodic patterns can be found in Islamic art, such as the Tomb of Hafez and the Nasr ol Molk mosque in Iran. They’ve been studied in the 17th century by Johannes Kepler and more recently by Roger Penrose, famous for his aperiodic “Penrose tilings”.

You can also see aperiodicity in quasicrystals, such as aluminium palladium manganese. In fact, Dan Schechtman won the 2011 Nobel Prize for Chemistry for discovering these materials.

Aperiodicity is now the theme of a festival of art, science, music and performance that’s been taking place this summer in Bristol, UK. It’s included an academic meeting, an exhibition and a wonderfully entertaining dance performance that I attended last week.

Anna Demming and three other dancers stood back to back — Making shapes: Anna Demming in action at the Aperiodic festival. (Courtesy: Matin Durrani)

Organized by my former Physics World colleague Anna Demming, a physicist and founding director of the South West Dance Theatre, the event was held at the city’s Trinity Centre. It began with a fun lecture on the science of aperiodicity by Sean Dewar, a mathematician from the University of Bristol, followed by 10 short dances that brought the subject alive.

Featuring Demming along with Katarzyna Niznik, Silvia Orazzo and Sebastián Morales Castillo, each dance – which combined classical ballet with breakdancing – was performed to a brilliantly eclectic mix of music ranging from Nina Simone and the BeeGees to Johann Sebastian Bach and Miley Cyrus.

I can’t imagine anyone has ever previously tried turning themes such as “Kepler’s tessellating pentagons”, “the limits of determinism” and “non-local indistinguishability and equivalence” into dance form, but that’s exactly what was on offer at the event.

There was even a nod to Hofstadter’s butterfly accompanied by Puccini’s O Mia Babbino Caro (pictured in the image at the top of this blog).

It was great fun – and even if the precise links of each dance with aperiodicity were slightly lost on me, I don’t think that really mattered. It was an event that simply got me – and the rest of the audience as well – thinking.

Spin-ice superconductors display magnetic nonreciprocity

Researchers in China have fabricated a new hybrid superconducting device from a special type of material known as an artificial spin ice (ASI). The innovative structure, which is made of asymmetric nanomagnets, could be used to build magnetic-field-driven superconducting diodes for use in energy-efficient electronics.

ASIs get their name from the fact that at low temperatures, their magnetic moments adopt the same disordered pattern typified by proton spins in water ice. They have a tetrahedral structure, with rare-earth ion moments occupying the corners in a way that obeys the so-called “ice rules”: two of the moments point into the tetrahedron, while two point out of it. In this configuration, the moments are unable to align, and the material is said to be geometrically frustrated.

The behaviour of the new ASI-based device is driven by a phenomenon known as the magnetic nonreciprocal effect, in which a material displays zero resistance along the direction of an applied magnetic field while continuing to have resistance in the opposite direction. “This is analogous to the behaviour of a superconducting diode and is a recently-discovered effect that is creating a flurry of interest in the field,” explains Yong-Lei Wang of Nanjing University, who led the research.

Asymmetric nanomagnets

To induce magnetic nonreciprocity, Wang and colleagues made their ASI from asymmetric nanomagnets. They created these nanomagnets by depositing a thin film of molybdenum germanium superconductor onto a silicon wafer using photolithography and magnetron sputtering techniques. They then fabricated the artificial spin ice on top of this structure, using electron beam lithography and evaporation to create an ASI with the nanomagnets arranged in a square lattice.

“Distinct from all previous ASIs, however, this structure contains asymmetric nanomagnets as opposed to symmetric ones,” explains Wang. “This leads to a novel superconducting pinning potential, resulting in the asymmetric motion of superconducting vortices when positive and negative magnetic fields are applied, thus allowing us to observe magnetic nonreciprocity.”

The Nanjing team has been working on ASI-superconductor heterostructures since 2018, when its members first reported on switchable geometric frustration and superconducting vortex diode effects. Two years later, the researchers made a switchable superconductor and programmable flux-quantum Hall effect device using another ASI-superconductor hybrid. Then, in 2021, they followed this by producing a superconducting diode in arrays of conformal-patterned nanoholes in superconducting thin films. “This last device works thanks to the spatial inversion symmetry breaking from the nanoholes and it allowed us to understand that the asymmetric nanomagnets in ASIs could induce unique symmetry breaking and lead to interesting superconducting effects,” Wang says.

The team’s findings could have implications for the development of advanced superconducting electronics, he tells Physics World. “Being able to control and reconfigure vortex dynamics in superconductors can lead to innovative devices such as magnetic field-driven superconducting diodes and rectifiers. These applications are particularly promising for low-power electronics, neuromorphic computing, and advanced sensing technologies.”

The researchers now plan to examine how temperature affects the magnetic nonreciprocal effects they observed. “We will also study the hysteresis behaviour of in-plane magnetic fields to enhance the nonreciprocal ratio of these effects,” reveals Wang. “We also plan to apply our method to other types of ASI structures, such as kagome-ASI and pinwheel-ASI, to explore a wider range of superconducting properties and functionalities.”

They detail their present work in Chinese Physics Letters.

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