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Radio gaga: surfing the long wavelengths of the universe

In the arena of public engagement, astronomy holds one distinct advantage over other areas of physics: the ability to generate an endless supply of pretty pictures. But not all astronomers benefit equally from this superpower – when it comes to capturing the punter’s imagination, it is optical astronomy that reigns supreme. Whether it’s the latest image of the Horsehead Nebula from the Euclid telescope or Voyager’s “Pale Blue Dot” photograph, this narrow band of the electromagnetic spectrum dominates public discourse on outer space.

It is with this in mind that astrophysicist and author Emma Chapman’s latest book is especially pertinent. A love letter to long-wavelength astronomy, Radio Universe: How to Explore Space Without Leaving Earth sheds a new (non-optical) light on a powerful and often overlooked tool in science: the radio wave.

Chapman takes us on a cosmic tour, starting with planet hopping across our solar system, before diving through the spiral arms of the Milky Way to explore black holes, neutron stars and the origin of our universe. At each stop, our tour guide outlines all that radio wavelengths have taught us about these phenomena, with humour and endearing appreciation. She also highlights some of the uphill battles for recognition fought by radio astronomers over the years.

Throughout the book, Chapman effectively outlines distinct advantages of radio waves over the visible spectrum. For starters, they are unattenuated by Earth’s atmosphere and dust in the intergalactic medium. This allowed radio astronomers to see further into both space and time; and with less expensive instruments. Moreover, a radio telescope’s ability to make observations is not hampered by bad weather – indeed, they can happily continue collecting data at day or night.

As Chapman explains, many of humankind’s biggest achievements are indebted to the radio wave. When astronauts first walked on the Moon in 1969, they relied on radio communications to keep them on course, while their safe landing site had already been selected from detailed maps of the lunar surface assembled by radar (radio detection and ranging).

As we fly with Chapman through the inner solar system, some of radio’s biggest strengths are highlighted in contrast to other means of exploration. Take Venus. Scientists in the Soviet Union admirably sent wave after wave of space probes (14 in total) as part of the Venera programme (1966–1982). Each one lasted mere minutes or hours on the surface before being crushed by the hellish pressures and temperatures of the Venusian atmosphere. Meanwhile, radar facilitated far more efficient surveys of the surface by both Russian and US spacecraft in orbit around the planet.

Chapman also explains how, in 1956, radio astronomers provided the first realistic (and apocalyptic) picture of life on Venus. This was in stark contrast to the earlier infrared-based measurements, which had suggested a tranquil and potentially life-supporting environment. It was later clarified that the infrared waves originated from the top of the Venusian atmosphere, whereas the longer wavelengths of radio revealed the nightmarish conditions below.

Chapman goes on to outline in astonishing detail all that radio waves have taught us about the best places to set up camp on Mars. Radar surveys of the Red Planet have uncovered secret caverns below the surface, which will provide future colonisers with access to subterranean water deposits and shelter from high-energy solar particles. Her coverage of this topic, in particular, is a masterclass in making science engaging, with Chapman playing the role of a Martian real-estate agent – “Valles Marineris is a very up-and-coming area, don’t you know?” – and I for one think she could be up for employee of the month.

Radio astronomy: from amateur roots to worldwide groups

A consistent and thought-provoking theme that emerges in Radio Universe is “seeing is believing”. On several occasions in history, we find radio-based discoveries requiring confirmation with some other “more visible” means of investigation as a prerequisite for widespread acceptance by the field. For example, it was not until we saw the first waveform of a gravitational wave detected by the LIGO detectors, in 2016, that these predictions of general relativity were considered confirmed. This was despite the indirect detection of gravitational waves through radio observations of pulsars more than four decades earlier.

Chapman highlights the emotional impact on the astronomy community, and the world as a whole, of the first image of a supermassive black hole, assembled with radio interferometry and unveiled in 2019 by the Event Horizon Telescope. Even with all of the faith we as scientists place in Einstein’s theory of gravity, the photographic proof of these unimaginable phenomena still resonated. As Chapman aptly puts it, “a picture tells a thousand equations”.

The book also highlights the ideological battles fought by radio practitioners over the years, from confirming the temperature of Venus to validating the Big Bang theory itself. One can’t help but wonder if this visible-centric view of the world is to blame for the apparent “radio scepticism”. Or is just a case of new kid on the block, given that radio astronomy only began in the mid 20th century, while optical imaging dates back much further?

Whatever the reason, this optical astronomer comes away from Chapman’s latest book with a newfound respect and appreciation for the longer wavelengths. And as far as Martian real-estate ventures go, sign me up for one of the new builds on Utopia Planitia. After all, the property prices can’t be as bad as inner-city UK living, can they?

2026 John Murray Press £25hb 352pp

Flying focus wakefields open a new acceleration regime

Conventional particle accelerators use radio frequency cavities to push particles to high energies, but these machines are vast and expensive. Laser wakefield accelerators (LWFAs) offer a radically different approach. When an intense laser pulse travels through a plasma, it drives a rippling disturbance called a wakefield. Electrons can be trapped in this plasma wave and surf along it, being boosted to very high energies over just centimetres.

However, these electrons tend to outrun the plasma wave that accelerates them, a limitation known as dephasing. One proposed way around this problem is the flying focus: a laser pulse engineered so that its point of highest intensity moves along the propagation axis at a controllable velocity. By matching this velocity to that of the electrons, the plasma wakefield could, in principle, remain phase locked to the particles, enabling sustained acceleration. While the flying focus concept has been theoretically developed and experimentally demonstrated in principle in recent years, the detailed structure and behaviour of the resulting wakefields has not yet been optimised for applications.

In a new study, a team of researchers from the Weizmann Institute of Science probed these wakefields directly, combining high resolution experiments with advanced simulations. Using femtosecond relativistic electron microscopy, the team sent a separate electron beam through the flying focus wakefield, allowing them to image its electromagnetic structure with micrometre spatial resolution and femtosecond timing.

The results reveal that flying focus wakefields are stable but highly structured, blending linear and nonlinear features and extending off axis in ways not seen in conventional laser driven wakefields. The study also shows that factors such as plasma density, composition and ionisation dynamics can significantly reshape the wake. These effects must be carefully modelled and controlled if the scheme is to deliver on its promise.

By opening a direct experimental window onto flying focus wakefields, the work provides the crucial insight needed to turn a compelling idea into a practical technology.

Read the full article

Probing flying-focus wakefields – IOPscience

Aaron Liberman et al 2026 Rep. Prog. Phys. 89 038501

Limits on communication in quantum measurements

Quantum technologies often imagine distant users – Alice and Bob – sharing entangled particles and trying to learn something about them. In principle, the most powerful measurements are global: Alice and Bob act as if their systems were in the same lab. In reality, they are usually limited to local operations and classical communication (LOCC). This means that each makes measurements locally and sends classical messages back and forth. A long standing debate is how much classical communication is actually required to perform a given quantum task.

In a recent article, Arthur Dutra and colleagues, tackled this question by analysing quantum measurements that use just one round of classical communication. Rather than treating LOCC as an all or nothing option, the team asked more precise questions. Who should measure first? How many classical bits are needed? Does Bob really need to adapt his measurement based on Alice’s message?

Their key contribution is a new mathematical framework that turns these questions into efficiently solvable optimisation problems. Using a hierarchy of semidefinite programmes (a standard tool in quantum information theory) the authors placed tight upper bounds on what one round LOCC measurements can achieve, even when the size and direction of the classical message are fixed.

Applying this framework to the task of guessing which quantum state was prepared (quantum state discrimination) they uncovered several surprises. In some cases, it matters a lot who measures first: Bob first strategies can outperform Alice first ones, even when only one classical bit is exchanged. Perhaps most interestingly, they showed concrete examples of adaptive strategies (those in which Bob’s measurement depends on Alice’s outcome) are provably more powerful than any non adaptive approach.

Beyond these examples, the work offers a general way to quantify classical resources in quantum protocols. As future quantum networks face practical limits on latency, memory, and bandwidth, knowing exactly how many bits must be communicated, and when, may be just as important as entanglement itself.

Read the full article

Structure of quantum measurements implementable with one round of classical communication – IOPscience

Arthur C R Dutra et al 2026 Rep. Prog. Phys. 89 037601

Physicists confirm proton radius is smaller than we thought

After more than 15 years of conflicting results, two independent measurements appear to have settled the debate over the charge radius of the proton. The new measurements, which are the most precise to date and are based on protons in normal atoms, suggest that the radius is 0.8406 femtometres (10^-15 m) – very close to the measured value that initiated the controversy back in 2010.

Charge radius is a measure of how far the electric charge of a particle extends into space. In protons, researchers have two main ways of measuring it. The first is by scattering electrons from hydrogen atoms, which consist of a single proton bound to an electron. The second is by analysing the Lamb shift, which slightly modifies the gap between energy levels of the hydrogen atom and arises from interactions between the electron and proton. According to the theory of quantum electrodynamics (QED), these interactions will be slightly different for electrons occupying different energy levels, so the resulting energy shift depends, in part, on the radius of the proton.

For many years, the accepted value of the proton radius – based on measurements by several groups around the world – was around 0.876 femtometres (fm). Then, in 2010, a team led by physicist Randolf Pohl at the Max Planck Institute of Quantum Optics (MPQ) in Garching, Germany performed a new measurement using muonic hydrogen. In this quasi-atomic system, the electron is replaced by its much heavier cousin, the muon. Muons are more tightly bound to the nucleus and therefore have a much higher probability of being very near – or indeed within – the proton. This makes their Lamb shift much more dependent on the proton’s radius.

Based on their measurement of the photon energy required to drive the 2S-2P transition in muonic hydrogen, Pohl and colleagues calculated that the proton’s radius was 0.8418 fm with an uncertainty of 0.0007 fm. This value disagreed substantially with previous measurements and was well outside the error bars of earlier results.

Physicists found this concerning because it implied that either QED theory had been misapplied or that the Standard Model of particle physics was somehow lacking. These concerns increased as subsequent measurements (on normal as well as muonic atoms) by various other groups produced some results that agreed with the 2010 finding, but also others that did not.

New measurements also yield a radius of about 0.84 fm

Both new studies involved placing hydrogen atoms in a vacuum and using laser light to control and measure transitions between different electron energy levels. In one of the studies, Thomas Udem and colleagues at MPQ measured the 2S-6P transition in atomic hydrogen with a precision 2.5 times higher than previous measurements, reaching the five sigma (5𝜎) threshold commonly used as a benchmark in the field. Thanks to this precision, they were able to test the Standard Model’s predictions to 0.7 parts per trillion (ppt) and the bound-state QED corrections to 0.5 parts per million (ppm).

The 2S-6P transition involves a single photon, which means it has fewer systematic corrections than the more commonly probed two-photon resonances. “Lower systematic corrections lower the possibility of making errors in those corrections,” notes MPQ team member Lothar Maisenbacher.

The downside is that the linewidth of the transition is very large compared to the precision the team needed to reach, but Maisenbacher says they were able to overcome this. “We succeeded in finding the centre of the resonance at 1 part in 15 000 of its width, which is (as far as we know) a world record for laser spectroscopy,” he tells Physics World.

The other work, by Dylan Yost and colleagues at the Colorado State University in the US, involved measuring three two-photon transitions (in 2S-ns, with n being between 8 and 10) that had not previously been studied for this purpose. Yost describes these transitions as “nice” because they are intrinsically narrow. “Generally speaking, narrower lines can be measured more precisely,” he explains. “This has us very excited that we may be able to really push our technique to higher precision with some modest additional technical improvements.”

The Colorado State researchers say that the three measurements they made were “very precise and agreed very well with each other”. By combining these results, they produced the most precise values for the proton radius to date based on two-photon spectroscopy, complementing the one-photon method used in the MPQ group’s 2S-6P measurement.

“Our new measurement, together with the new result from the Garching group and the muonic hydrogen measurements, are now the most precise spectroscopic measurements of the proton radius and all show extremely good agreement,” says Yost. “Personally, I find it remarkable that the theorists working on the required bound-state QED calculations have been able to make such accurate and reliable predictions and that these predictions have now been tested and show agreement at the parts-per-trillion level.”

The most precise spectroscopic measurements of the proton radius

According to Meisenbacher, the 2010 muonic result has now been thoroughly tested, and the proton radius puzzle has been resolved in a way that suggests that both the Standard Model and QED theory remain valid. “Our result also confirms that muonic spectroscopy is a powerful tool for studying nuclear properties,” he says. “Indeed, the community is working on extending it to heavier atoms.”

Both groups now want to repeat their measurements in atomic deuterium, where the nucleus contains a neutron as well as a proton. A similar discrepancy exists in this nuclear charge radius and measuring it precisely could reveal a hitherto undetected interaction between the electron and the neutron that is not included in the Standard Model.

Nottingham physics redundancies ‘an act of academic sabotage’, warn scientists

Almost 2000 scientists have signed an open letter criticising planned redundancies at the University of Nottingham in the UK. The signatories, which includes six Nobel laureates, call on the university to reverse its plan to reduce the number of staff members in the physics department from 71 to 51.

News of the possible job losses emerged on 12 May, when 2700 Nottingham staff were sent letters saying they were at risk of redundancy as part of plans to slash more than 600 academic posts throughout the university. The university says it is making the move because it could otherwise run out of money within the next five years.

Nottingham is a member of the “Russell Group” of 24 leading, research-intensive universities in the UK, with its school of physics and astronomy ranking seventh out of 44 UK physics departments in the most recent REF assessment. It is famous for its work on magnetic resonance imaging, through the contributions of the Nottingham Nobel-prize-winning physicist Peter Mansfield.

From the 2700 staff receiving letters, 56 are in physics and represent academic and technical staff across all levels. Antonio Padilla, a particle theorist at Nottingham, told Physics World that putting almost all members of physics staff at risk is an “act of academic sabotage”.

It takes years of dedication to build up a world-class reputation. I worry that it can be destroyed much more quickly
Antonio Padilla, University of Nottingham

“This is a school brimming with creativity and innovation,” he says. “There is excellence in all areas of physics, from particles to astronomy, from condensed matter to medical imaging. It takes years of dedication to build up a world-class reputation. I worry that it can be destroyed much more quickly.”

The open letter created by researchers at Nottingham in response to the cuts says that the proposals will cause “long-lasting damage” to what they claim is a “globally respected physics department”. It urges senior leaders at Nottingham to work with the University and College Union (UCU) to create “a more sustainable vision for physics and astronomy at the university”.

Stating that the job cuts will lead to fewer students applying to the university due a “decline in its reputation”, as well as a loss of student income, the letter has so far been signed by six physics Nobel laureates – Andre Geim, Andrea Ghez, Konstantin Novoselov, Roger Penrose, Didier Queloz and Brian Schmidt. Geim was once a postdoc at Nottingham.

“Physics underpins current and future economic developments; from AI, through quantum technologies to new medical imaging techniques,” the letter states. “Cutting the university’s strength in these areas is a short-sighted move that will deprive Nottingham students and the East Midlands of the capability to take advantage of these opportunities for growth.”

The university should exhaust every option to make the department sustainable before resorting to compulsory redundancies; shrinking it now is shortsighted
Catherine Heymans, Astronomer Royal for Scotland

Catherine Heymans, Astronomer Royal for Scotland, who has signed the letter, says that the UK needs “strong, geographically distributed physics departments” to help diversify the economy away from just a few centres. “The university should exhaust every option to make the department sustainable before resorting to compulsory redundancies; shrinking it now is shortsighted,” she says.

Those comments are echoed by Jim Wild, president of the Royal Astronomical Society, who urges Nottingham to reconsider the short-sighted cuts. “Reducing staff capacity by this magnitude will irreparably damage a world-class department, severely harming both its international reputation and its capacity to deliver high-quality education,” he says.

A ‘more careful approach’

Padilla, who is UCU representative for Nottingham’s physics and astronomy department, says that “a more careful approach” is required to protect staff at the university. He points out that the UCU has proposed an alternative financial model for the university that “doesn’t set fire to our academic reputation”.

After two decades in which the UK university sector has boomed, there are now fears that the problems at Nottingham could be replicated elsewhere. “What happens at Nottingham now matters for the rest of the sector,” adds Padilla. “This isn’t just make or break for physics at Nottingham – it matters for science everywhere in the UK and beyond.”

Philip Moriarty, another at-risk Nottingham physicist, says that the UCU offer, which he says has been “carefully considered, costed and modelled” has been “rejected, out of hand, with no justification by the university”. Senior management at the university, he adds, “have provided no evidence to support their strategy, including, in particular, their university-wide 18-22 student-staff ratio target”.

On 18 May all affected staff across the university were sent an e-mail to participate in a “supporting you during change” programme that involves two 90-minute online webinars “to help you consider the proposed changes that have been announced and to help you plan for what you may wish to do next”.

“Nauseatingly, even the provision of ‘support’ for staff during this process has been outsourced to an external consultancy company,” adds Moriarty. “Alongside the complete disregard for data and evidence, it’s the disingenuousness and dishonesty that rankle most. Their repeated claims that they care about staff are baseless.”

In a statement, a spokesperson at the University of Nottingham noted that “doing nothing is not an option” given the “significant financial challenges” the university faces.

“We know that change of this scale is not easy, and we do not underestimate what it means for many of our colleagues and students. We will be doing everything we can to support our people through the next few months,” the statement says. “These are really difficult decisions and we have not taken them lightly. It is vital that we respond to the changing sector demands to ensure we are sustainable for future generations and continue to deliver world leading teaching and research and an excellent student experience.”

Why is rubber so resilient?

People have been using reinforced rubber for nearly a century, but we still don’t know why it’s so strong. Researchers at the University of South Florida (USF) in the US now say they may have the answer thanks to advanced molecular dynamics simulations. Their work could make it possible to design new materials that are safer and have even better mechanical properties.

Reinforced rubber is made by adding a nanoparticle filler – typically carbon black or silica – to elastic polymers (elastomers). The presence of this nanofiller explains why tyres, industrial seals and many other everyday rubber products tend to be black in colour. More importantly, the nanofiller makes the material robust to heat and able to withstand millions of cycles of deformation, meaning that objects can last for years, or even decades, without deteriorating.

One property that may play a central role in the materials’ mechanical performance is the stickiness of the nanofillers’ surfaces. This enables them to attract and immobilize nearby polymer segments, but USF engineer David Simmons, who led this new research effort, says the exact mechanism remains an enigma because it is hard to differentiate between the many physical processes that may be at play.

“I love this kind of problem,” Simmons says, adding that it combines “massive practical impact” with “a deep fundamental scientific question that has resisted resolution for so long that much of the field has moved on to different problems”.

A model that distinguishes between mechanisms

To disentangle the different processes, Simmons and his colleagues conducted molecular dynamics simulations of elastomeric nanocomposites. These simulations incorporated strong polymer-particle attractions, with the strength controlled by a parameter known as ϵ_{P F}.

A photo of the researchers wearing a black blazer — Material man: University of South Florida engineer David Simmons. (Courtesy: USF)

The team studied how ϵ_{P F} and various other parameters, including nanoparticle filler loading ϕF and structure N_p, affected various reinforcement mechanisms by measuring several parameters. These included the nanocomposite’s bulk and Young’s moduli; the Poisson’s ratios for pristine and filled elastomers; and the time required for the nanocomposite to relax after being stretched.

The team then used this model to explore four possible ways that strong polymer-particle attractions might, hypothetically, increase mechanical strength. The first of these is called strain localization. If this was the key factor, strong attractions could immobilize the surrounding polymer, straining the remaining mobile elastomer domains. “This ‘bound-rubber’ mechanism was popular in the early literature,” Simmons notes.

The second mechanism is known as glassy bridging. The idea here is that regions of polymer between particles could vitrify, forming links that elongate the cohesive nanoparticle network.

The third mechanism is called transient crosslinking. Under this hypothesis, slower-moving or stationary polymer regions around particles, or adhesions to the particles themselves, act as long-lived physical crosslinks in the matrix. “This could increase the effective crosslink density of the rubber, thereby increasing the entropic elastic modulus of the polymer domains,” says Simmons.

The fourth and last mechanism is a Poisson’s ratio mismatch. Poisson’s ratio measures how materials change shape when stretched, and a mismatch between ratios for the rubber and the nanoparticles would essentially force rubber to “fight” against its own incompressibility.

And the winner is…

The results of the study, which is detailed in PNAS, show that while all four of these mechanisms play a role in reinforcing the nanocomposites, the most important is the Poisson’s ratio mismatch.

“This is an incredibly cool result because it tells us that the strength of nanocomposites doesn’t come from their polymer-like elasticity but from their resistance to volume expansion,” Simmons says. “This is an entirely different picture than the field has held for more than 80 years. What’s more, we’ve shown that some of the other leading proposed mechanisms from these past decades (for example, particle network percolation, sticky interactions and space-filling effects) actually contribute to this mechanism, enhancing it and making it more effective in strengthening rubber.”

The biggest barrier to obtaining these findings, Simmons adds, was that these materials are difficult to simulate at a molecular level. “They involve very large system sizes, very large timescales and very complex processing histories,” he says. He highlights the work of two lab members – postdoctoral researcher Pierre Kawak and PhD student Harshad Bhapkar – as “instrumental” in overcoming these challenges to generate “beautiful and insightful” simulations of these systems.

As for the work’s impact, Simmons tells Physics World that it could provide a new foundation for rational design of elastomeric nanocomposites with transformative mechanical properties. “Let’s take the tyre industry alone, for which it is important to design a rubber that combines good traction, durability and fuel economy,” he says. “The industry has had to very empirically navigate this space of competing properties – they call it the ‘magic triangle’. Our findings could help design this triangle with a grasp of the fundamental principles that govern reinforcement in these systems.”

The researchers are now trying to better understand how elastomeric nanocomposites ultimately fail and determine how this failure can be predicted and even delayed. Their work is supported by the Mechanical Properties and Radiation Effects programme within the US Department of Energy.

Quantum science in the heart of Dublin

<strong>Graduate students</strong> at Trinity College Dublin. (Courtesy: Matt Boyd/Mahoo) — **Graduate students** at Trinity College Dublin. (Courtesy: Matt Boyd/Mahoo)

The impact of quantum science and technology is going to be profound, with quantum computing in particular – but also quantum sensing, simulation and communication – set to be a major driver of economic growth and sustainable development in countries around the globe.

Ireland is no exception. It is already home to some of the world’s largest technology companies, many of which are heavily investing in quantum technologies. Moreover, the country’s quantum research and innovation community demonstrates a significant level of expertise in fundamental quantum science and quantum technology.

But to ensure Ireland is not only a user of quantum technologies but an active contributor to its development long into the future requires both strong partnerships with industry and public research bodies across borders, and the consistent production of people with the talent and skill to push quantum science forward.

Transferable skills across academia and industry

Founded in 1592, Ireland’s oldest university Trinity College Dublin hosts a future-focused MSc Quantum Science and Technology programme that fits this remit perfectly. The one-year master’s course is the ideal stepping stone into a career in quantum research, whether students want to advance fundamental knowledge in academia or develop the next world-leading quantum technology in industry.

**Professor Felix Binder** Course Director of Quantum Science and Technology MSc, Trinity College Dublin. (Courtesy: Matt Boyd/Mahoo)

“Unlike other fields, for many of the exciting positions in industry, the skills are very similar to what would be required of a PhD student,” explains quantum information theory expert Professor Felix Binder, who directs the course. “It’s a level of scientific rigour, it’s having a broad knowledge base and coding skills, it’s being confident to independently work on a project – these are what we focus on.”

This is why the course very much leans into helping students develop the fundamentals. Topics such as quantum computation, quantum information theory and open quantum systems are covered in depth. This provides the foundation for exploring more advanced and specialized topics, like quantum materials or tensor network theory.

The combination of fundamentals and highly specialized knowledge is designed to equip students with skills that are relevant for the long term, says Binder. Though he acknowledges that now is an exciting time when many quantum technologies are maturing and being commercialized, the course generally looks beyond the latest fads.

“If students are choosing quantum as their profession, realistically they’re looking at a potential 40-year career,” he says. “As this is their last part of formal lecture-based education, we want to be sure that we set them in good stead for at least many years, and not just the immediate future.”

Career insights

In addition to preparing students with the knowledge they will need, the course also exposes students to people working at the cutting-edge of the subject, providing them with an understanding of the types of careers available and contacts to build their network and take the first steps towards their chosen quantum profession.

For instance, world-leading academic and industry experts deliver a range of short mini-modules and specialist lectures. Some of these experts come from companies involved in the Trinity Quantum Alliance. “The Trinity Quantum Alliance is a unique space on campus where fundamental quantum science and research meets real-world applications,” says the Alliance’s Director Professor John Goold. “Here, multinational companies, SMEs and start-ups come together to work on projects with Trinity academics.”

The founding industry partners are Microsoft, IBM, Moody’s, Horizon Quantum Computing and Algorithmiq. Each partner shares research and regularly presents talks to faculty and students, and most have a presence on or near the Trinity campus. This arrangement offers students direct access to the people shaping the quantum revolution, as well as potential internship opportunities.

Microsoft Ireland scholarship awardees 2023/24 — **Microsoft Ireland scholarship awardees** **2023/24** Srishti Nautiyal, Grainne Eager and Nana Werther. (Courtesy: Gary Ashe/SHARPPIX)

Further experts who have given guest lectures and shared their experiences are alumni. Several are completing PhDs at various universities dotted across the world, from the EU to the US and Australia. Many have gone on to become full-time researchers and even team leads in quantum companies, including Quandela, Horizon, Algorithmiq and EleQtron, as well as companies traditionally not associated with quantum technology, such as MasterCard. Others have taken positions at government labs across European countries, including a Max Planck Institute in Germany and a national research centre in the UK.

Although this alumni network may be relatively small – with the course having only been running for five years and graduating 60 students – it is extremely useful for the current cohort, showcasing the different paths potentially available to them and providing contacts who can offer support and advice on how to enter and thrive in those careers.

A quantum future for the Emerald Isle

Looking forward, Binder envisions even closer integration of the MSc degree and doctoral training into the European quantum ecosystem. This will be enabled through a new EU-wide training network: the European Quantum Academy. Trinity is one of the lead institutions of this new training academy, which was launched in May 2026. Composed of more than 70 partner institutions from across Europe, it will open new opportunities to students in Ireland in terms of industry interaction, international exchange and advanced training beyond the degree’s core modules.

In addition, there are ongoing plans for further research investment in Ireland, bringing together the different schools within Trinity, and other universities and industry players to work more closely together.

The result of these efforts should be a thriving quantum ecosystem that takes advantage of Ireland’s unique position within the EU and close ties with the US and UK to provide ever more new and varied opportunities in quantum science and technology, as Binder succinctly summarizes: “The field is young and growing – Ireland is a very exciting space for quantum right now”.

MSc students in Dublin city centre Trinity College campus — **MSc students in Dublin** **city centre** Trinity College campus, in close proximity to many of the world’s largest tech companies. (Courtesy: Matt Boyd/Mahoo)

Applications for Trinity’s MSc Quantum Science and Technology are now open for the next academic year. Find out more and apply: www.tcd.ie/physics/quantumtech/

Switchable skyrmions light up terahertz communications

**Switchable free-space skyrmions** Researchers used a nonlinear metasurface to experimentally demonstrate that skyrmions can be switched between electric and magnetic modes in free-space toroidal terahertz light pulses. (Courtesy: Li Niu and Xueqian Zhang, Tianjin University)

There is a shape in physics that is remarkably hard to destroy. You can shake it, heat it, push it and disturb it in every way imaginable, but unless you physically tear the fabric it resides in, it will survive perfectly intact. This is not wishful thinking. It is a mathematical certainty. That shape is called a skyrmion.

The easiest way to picture a skyrmion is to imagine a dartboard covered in tiny arrows. At the very centre, every arrow points straight down into the board. At the outer edge, every arrow points straight up. In between, they rotate smoothly through every possible direction, completing a full rotation and closing back on themselves. This pattern has a score called the skyrmion number, and that score is locked at exactly ±1 (the sign simply defines which way the twist runs). Noise cannot nudge it. Heat cannot drift it. A stray disturbance cannot flip it. The only way to change it is to violently rip the whole pattern apart.

Scientists first found skyrmions hiding inside certain magnetic materials and immediately recognized them as dream candidates for carrying information (a skyrmion present means 1, a skyrmion absent means 0, and nothing in the environment can accidentally corrupt it). But magnetic materials are slow and confined to a chip. The next natural question was bold: what if you could take this indestructible shape and put it inside light itself, travelling freely through open space?

A team of researchers from Tianjin University in China, together with collaborators at Nanyang Technological University in Singapore and Oklahoma State University in the US, has now done exactly that – and gone one step further. As described in Optica, the researchers created not just one skyrmion in light, but two completely different kinds, and found a way to switch between them at will using nothing more than the rotation of a single thin optical half-wave plate.

The two types are an electric skyrmion, where the topological twist lives in the electric field of the light wave, and a magnetic skyrmion, where the same twist lives in the magnetic field. And they are as distinct from each other as a left-handed knot is from a right-handed one.

To generate these skyrmions, project leader Jiaguang Han and colleagues built a flat chip roughly the size of a small stamp, its surface packed with thousands of tiny C-shaped gold antennas, each one far smaller than a bacterium. When a structured laser beam hits this chip, the antennas absorb the incoming near-infrared light and re-radiate it as terahertz waves.

The key is how the antennas are arranged on the chip: one set is laid out in concentric rings pointing outward, while another set spirals around the centre like the spokes of a wheel. Each arrangement, when activated by the right kind of laser beam, generates a different skyrmion-carrying light pulse. Switching the laser from one beam shape to the other is done by rotating a single optical plate by just 45°, which flips the chip from producing one skyrmion type to the other, instantly and cleanly.

“The core innovation lies in the nonlinear metasurface that converts shaped near-infrared femtosecond laser pulses into tailored terahertz toroidal light pulses,” explains first author Li Niu in a press statement.

The team confirmed this process by mapping the full three-dimensional structure of each light pulse at multiple positions in space and time. The skyrmion numbers they measured came out at –0.990 and +0.992 for electric skyrmions, and –0.991 and +0.994 for magnetic skyrmions, within 1% of the mathematically perfect value of ±1. The tiny deviation from a perfect score of ±1 is simply down to the limits of any real measurement – sampling a fleeting pulse of light in three dimensions will always leave a small rounding error. However, the topology itself remains exactly intact.

The importance of this result reaches far beyond the elegance of the experiment. The next wave of wireless communication technology – already being designed to operate at terahertz frequencies, which can carry vastly more data than current mobile networks – has a serious enemy: the real world. Humidity, atmospheric turbulence, buildings and even rain can scramble a terahertz signal in ways that are very hard to protect against.

Conventional optical signals encode information in the brightness or precise timing of a wave, but both of those are fragile; noise corrupts them the same way that a smudge ruins ink on paper. A skyrmion signal is fundamentally different. The information is encoded in the topological shape of the light pulse, and that shape cannot be accidentally altered by the environment. It is protected not by better engineering or thicker shielding, but by mathematics itself.

On top of that, having two switchable skyrmion states, electric and magnetic, effectively enables two distinct channels of information to travel along the same beam, doubling the capacity without using any extra bandwidth.

What this team has built is a proof of concept for a new kind of communication: one where the message is written in a shape that the universe, by its own rules, refuses to erase.

Earth’s magnetic field could be ‘ringing’ with dark matter

Analysis by physicists in China suggest that if dark matter carries even a tiny electric charge, it will generate a magnetic “hum” in Earth’s geomagnetic field. And what is more, data from existing magnetometer networks can already constrain this effect.

Dark matter is one of the biggest open questions in modern physics. Astronomers infer the existence of hypothetical dark-matter particles from their gravitational influence. The invisible presence of dark matter explains why galaxies rotate too rapidly for their visible mass, for example. Also, the gravitational lensing of starlight suggests a similar invisible mass in galaxy clusters. Yet the exact nature of dark matter particles remains unknown.

Ariel Arza at Nanjing Normal University and colleagues have explored what happens if dark matter carries a tiny electric charge, far smaller than that of an electron. The charge would be so small that dark matter would still be effectively “invisible” to most particle-physics experiments. However, the researchers argue that Earth’s own magnetic environment could turn our planet into a huge dark-matter detector.

Millicharged dark matter

This idea of millicharged dark matter (mDM) appears in several extensions of the Standard Model of particle physics, especially where the visible sector and a hidden dark sector mix slightly. In such models, dark matter can acquire a minuscule effective coupling to electromagnetism. Not enough to behave like ordinary charged matter, but enough to open new detection channels.

In a recent study described in Physical Review Letters , Arza and colleagues focused on bosonic mDM in the ultralight regime. This regime is particularly interesting because ultralight dark matter would behave collectively like a coherent wave, which makes its signal easier to model and search for in frequency space. This wave picture predicts a nearly monochromatic signal at a frequency tied directly to the dark-matter mass.

Earth as a dark matter detector

If dark matter has an extremely tiny electric charge and behaves like an oscillating field, it can act like a weak source that drives a small alternating current. In Earth’s magnetic field, that current would create an extra magnetic signal, a faint, repeating “hum” added to the usual geomagnetic field. This hum should appear at a specific, well-defined frequency set by the dark-matter mass, rather than being spread across many frequencies like most natural magnetic noise. In the mass range for this study, the signal is predicted to get stronger for lighter dark matter (roughly scaling like 1/m², where m is the dark-matter particle mass).

At the very low frequencies expected for ultralight millicharged dark matter, the electromagnetic fields change slowly, almost like steady magnetic fields with a small repeating wobble added on top. The ground acts like a conducting boundary below and the ionosphere acts like another conducting boundary above, so together they shape how these low-frequency magnetic signals travel and spread. Instead of needing to build a special resonant chamber in a lab, the “detector” is the space around Earth itself.

Testing with real data

The researchers predict that mDM would result in a narrow, single-frequency signal in Earth’s magnetic field. The frequency of the signal is determined by the dark-matter mass and the signal’s amplitude defined by dark matter’s tiny electric charge.

Azra and colleagues looked for this signal in real magnetometer data. They used null (no-signal) results from two major efforts: SuperMAG, which combines geomagnetic measurements from stations around the world, and SNIPE Hunt, which searches magnetometer data for narrow, single-frequency signals that could indicate new physics. Since neither dataset shows the persistent monochromatic oscillation expected from ultralight mDM, they used this absence of a signal to set upper limits on how large the dark matter’s tiny electric charge could be, for particle masses roughly in the range 10⁻¹⁸–10⁻¹⁴ eV/c².

Constraining mDM has already been done using astrophysical observations – for example, looking for the effect of mDM on how stars lose energy. However, these bounds often rely on complex environments and modelling assumptions. This latest study demonstrates that Earth-based magnetometer data can be just as powerful. Indeed, the ultralight mass range the researchers find limits that exceed stellar-cooling constraints by more than 13 orders of magnitude in some cases.

Modelling choices

Because the team’s argument relies on modelling choices (like boundary conditions and simplifying limits), one might question how sensitive the results are to these choices. Team member Jing Shu at Peking University in China, tells Physics World that the final calculation is not limited to the small-parameter approximation. “Our calculation is valid across the full parameter space of ε and κ, not only in the ε, κ ≪ 1 regime.” Here, ε is the dark matter charge, and κ is its electromagnetic coupling. He explains that the small-ε, small-κ discussion is mainly there to give a clearer physical picture.

The researchers also note an important limitation: if the dark matter’s tiny charge is still “too large,” Earth’s magnetic field can deflect it enough that the signal no longer keeps increasing and instead levels off. Related to this, Shu explains that the result does depend on ionospheric conductivity because it helps set the boundary conditions of the Earth’s ionosphere cavity. “Variations in conductivity, for example due to solar activity effectively modify this boundary and therefore change the geometric factors that determine the signal amplitude. In practice, this leads to variations that can be on the order of unity in the predicted signal.”

Finally, Shu says the next step is to make the search more targeted and coordinated. “A natural next step is to carry out dedicated measurements in electromagnetically quiet environments, for example in remote field sites across different locations in China, and to build a coordinated network of magnetometers.” This would help distinguish a global, coherent signal from local noise and improve sensitivity to weak oscillations.

‘Knowledge comes, but wisdom lingers’: how Alfred Tennyson drew science into his poetry

Alfred Tennyson was “the only poet since the time of Lucretius who has taken the trouble to understand the work and tendency of the men of science” said the English biologist Thomas Huxley on the occasion of Tennyson’s burial in the Poets’ Corner of Westminster Abbey on 12 October 1892. Tennyson’s acquaintance with science and its impact on his poetry is the subject of historian and broadcaster Richard Holmes’s new book The Boundless Deep: Young Tennyson, Science and the Crisis of Belief.

Born in 1809 – the same year as Charles Darwin – Tennyson matured at a time when science was transforming ideas about the universe. “It was stranger and vaster than previously thought,” writes Holmes, “and yet more vulnerable and paradoxically, more temporary. There were no Biblical eternities anymore.”

As a teenager Tennyson looked through telescopes and microscopes, and read books on physics, chemistry, botany and astronomy. In notebooks he interspersed poetic verses with careful observations of plants, birds, animals and other natural phenomena. In one poem he imagined himself on the Moon’s surface, in another as a microscopic creature. His verses expressed both wonder and suspicion. “O suns and spheres and stars … are you realities or semblances?” wrote the 14-year-old poet.

An unbreakable bond

While studying at the University of Cambridge, Tennyson met Arthur H Hallam and the two became inseparable, sharing interests in nature, poetry and science. In 1833 they spent a “science week” in London, visiting the new London Zoo in Regent’s Park, the Gallery of Practical Science in Piccadilly, and displays of magnets, microscopes and steam cannons.

That year several books on astronomy appeared, including one by Tennyson’s Cambridge tutor William Whewell, who coined the term “scientist”. The publications acquainted readers, including Tennyson and Hallam, with newly discovered star systems and “the nature of their formation, their growth over immense and previously inconceivable periods of time, and finally their slow but inevitable extinction”, as Holmes describes. “These ideas of so-called deep time and deep space were gradually transforming the whole notion of the material universe.”

That autumn, at age 22, Hallam unexpectedly died from a brain haemorrhage. It was the most traumatic event of Tennyson’s life, “a particular extinction from which he never recovered”, writes Holmes. Tennyson spent nearly two decades coping by writing In Memoriam A H H, published in 1850. In several sections near the poem’s midpoint, Tennyson seems to invoke nature as a possible source of solace in imagery that has challenged scholars ever since.

“Every evolutionist can cite the line,” wrote the evolutionary biologist Stephen J Gould in his 1995 book Dinosaur in a Haystack. “We would draw and quarter any imposter who couldn’t.” Gould was referring to the line “Nature red in tooth and claw”, a phrase from In Memoriam that many scholars think anticipates Darwinian evolution and consoled Tennyson. But Gould instead finds that the line only reflects the biological and geological catastrophism of Tennyson’s time and adds that Tennyson knew it held no comfort. “Science cannot tell us why a man should die so young,” Gould writes, “or how a grieving lover should resolve his suffering.”

Holmes gives a more nuanced interpretation, saying that Tennyson did not grieve and then seek solace in science. Rather, Tennyson’s grief began with his awareness that scientific truths prevented him from turning to religion; that the “death of an individual”, as Holmes writes, “counted for nothing within the vast and pitiless scale of geological death and extinction”. Tennyson’s grief sprang from his experience of a conflict between science and religion, which put him in a “state of hovering, or trembling, between science and religion, between empirical evidence and traditional faith”.

Life, poetry and science

Holmes has spent his career writing about Romantic poets and their world. For example, one of his previous books was The Age of Wonder: How the Romantic Generation Discovered the Beauty and Terror of Science. Holmes’s vast command of the era shows in his ability to identify the people from whom Tennyson learned what he knew.

He introduces us to Jane Marcet, an innovative scholar and writer whose books about physics and chemistry inspired not only Tennyson but also embarked the geologist Charles Lyell and physicist Michael Faraday on their scientific careers. Marcet would have been elected to the Royal Society, Holmes writes, “except for the slight hindrance that no female Fellow was admitted until 1921”. (Marcet’s husband, a Swiss doctor, made it in.) Meanwhile, the mathematician Mary Somerville – said to be “one of the only six persons in England who understands Laplace” – was a polymath whose books acquainted Tennyson with the entire spectrum of hard sciences.

Science, Holmes shows, is not a privileged knowledge that poets must bow before, nor a set of facts to accept or deny. Rather, its constant development reshapes our experience of the world as much as families and friendships, mentors and myths. The Boundless Deep is as instructive about the science found in Tennyson’s poetry as it is about science in human experience.

2025 William Collins 448 pp; £25.00 hb; £14.99 ebook

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