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Mathematical model sheds light on how exercise suppresses tumour growth

Physical exercise plays an important role in controlling disease, including cancer, due to its effect on the human body’s immune system. A research team from the USA and India has now developed a mathematical model to quantitatively investigate the complex relationship between exercise, immune function and cancer.

Exercise is thought to supress tumour growth by activating the body’s natural killer (NK) cells. In particular, skeletal muscle contractions drive the release of interleukin-6 (IL-6), which causes NK cells to shift from an inactive to an active state. The activated NK cells can then infiltrate and kill tumour cells. To investigate this process in more depth, the team developed a mathematical model describing the transition of a NK cell from its inactive to active state, at a rate driven by exercise-induced IL-6 levels.

“We developed this model to study how the interplay of exercise intensity and exercise duration can lead to tumour suppression and how the parameters associated with these exercise features can be tuned to get optimal suppression,” explains senior author Niraj Kumar from the University of Massachusetts Boston.

Impact of exercise intensity and duration

The model, reported in Physical Biology, is constructed from three ordinary differential equations that describe the temporal evolution of the number of inactive NK cells, active NK cells and tumour cells, as functions of the growth rates, death rates, switching rates (for NK cells) and the rate of tumour cell kill by activated NK cells.

Kumar and collaborators – Jay Taylor at Northeastern University and T Bagarti at Tata Steel’s Graphene Center – first investigated how exercise intensity impacts tumour suppression. They used their model to determine the evolution over time of tumour cells for different values of α0 – a parameter that correlates with the maximum level of IL-6 and increases with increased exercise intensity.

Temporal evolution of tumour cells

Simulating tumour growth over 20 days showed that the tumour population increased non-monotonically, exhibiting a minimum population (maximum tumour suppression) at a certain critical time before increasing and then reaching a steady-state value in the long term. At all time points, the largest tumour population was seen for the no-exercise case, confirming the premise that exercise helps suppress tumour growth.

The model revealed that as the intensity of the exercise increased, the level of tumour suppression increased alongside, due to the larger number of active NK cells. In addition, greater exercise intensity sustained tumour suppression for a longer time. The researchers also observed that if the initial tumour population was closer to the steady state, the effect of exercise on tumour suppression was reduced.

Next, the team examined the effect of exercise duration, by calculating tumour evolution over time for varying exercise time scales. Again, the tumour population showed non-monotonic growth with a minimum population at a certain critical time and a maximum population in the no-exercise case.  The maximum level of tumour suppression increased with increasing exercise duration.

Finally, the researchers analysed how multiple bouts of exercise impact tumour suppression, modelling a series of alternating exercise and rest periods. The model revealed that the effect of exercise on maximum tumour suppression exhibits a threshold response with exercise frequency. Up to a critical frequency, which varies with exercise intensity, the maximum tumour suppression doesn’t change. However, if the exercise frequency exceeds the critical frequency, it leads to a corresponding increase in maximum tumour suppression.

Clinical potential

Overall, the model demonstrated that increasing the intensity or duration of exercise leads to greater and sustained tumour suppression. It also showed that manipulating exercise frequency and intensity within multiple exercise bouts had a pronounced effect on tumour evolution.

These results highlight the model’s potential to guide the integration of exercise into a patient’s cancer treatment programme. While still at the early development stage, the model offers valuable insight into how exercise can influence immune responses. And as Taylor points out, as more experimental data become available, the model has potential for further extension.

“In the future, the model could be adapted for clinical use by testing its predictions in human trials,” he explains. “For now, it provides a foundation for designing exercise regimens that could optimize immune function and tumour suppression in cancer patients, based on the exercise intensity and duration.”

Next, the researchers plan to extend the model to incorporate both exercise and chemotherapy dosing. They will also explore how heterogeneity in the tumour population can influence tumour suppression.

US ploughs $50m into sodium-ion battery development

The US Department of Energy (DOE) has awarded $50m to a consortium of national laboratories and universities to develop sodium-ion batteries as a sustainable, low-cost alternative to lithium-ion technology.

Lithium-ion batteries currently dominate the electric-vehicle market and they are also used in smartphones and to store energy from renewable source such as wind and solar. Yet relying on a single battery technology such as lithium-ion creates dependencies on critical elements such as lithium, cobalt and nickel.

Sodium, however, is an abundant, inexpensive element and offers a promising way to diversify battery materials. The downside is that sodium-ion batteries currently store less energy per unit weight and volume than lithium-ion batteries.

The money from the DOE over the next five years will be used to create the Low-cost Earth-abundant Na-ion Storage (LENS) consortium. LENS will be led by Argonne National Laboratory and includes five other DOE national laboratories such as Brookhaven, Lawrence Berkely and Sandia as well eight US universities.

By leading the LENS consortium, Argonne will push sodium-ion battery technology forward and contribute to a secure energy future for everyone,” notes Argonne director Paul Kearns. ​Our scientific expertise and dynamic collaborations in this important field will strengthen US competitiveness.”

The LENS consortium will now develop high-energy electrode materials and electrolytes for sodium-ion batteries as well as design, integrate and benchmark battery cells with the aim of creating high-energy, long-lasting batteries.

“The challenge ahead is improving sodium-ion energy density so that it first matches and then exceeds that of phosphate-based lithium-ion batteries while minimizing and eliminating the use of all critical elements,” says LENS consortium director Venkat Srinivasan.

  • Venkat Srinivasan, William Mustain and Martin Freer appeared on a Physics World Live panel discussion about battery technology held on 21 November 2024, which you can watch online now

A ‘quantum rose’ for the 21st century: Oksana Kondratyeva on her stained-glass art inspired by a quantum computer

Stained glass is the most “physical” of all art forms. If you’ve ever been inside Chartres Cathedral in France or York Minster in the UK, you’ll know how such glass can transform a building by turning sunlight into gloriously captivating multicoloured patterns. What you might not realize, however, is that centuries of scientific innovation have forged this form of art.

Byzantine glaziers started making leaded glass windows back in the 6th century CE before the technique spread widely across Europe. But our ability to stain glass only emerged in the 14th century when medieval alchemists found that coating glass with silver nitrate and firing it in a kiln gave the material a range of orange and yellow hues.

Later, a range of other techniques were developed to produce various decorative effects, with stained glass becoming both an art and a craft. Particularly important has been the use of hydrofluoric acid – a poisonous and highly corrosive liquid – to strip off the surface of glass, layer by layer, to alter its colour and thickness.

Known as hydrofluoric acid etching, the technique is widely used by modern architectural glass artists. Beautiful patterns can be created by altering the strength and temperature of the acid and varying the time for which the glass is exposed to it. Materials like wax, bitumen and lead foil can also be used as resists to leave parts of the glass untouched.

Like other “glass artists”, I am an experimentalist of sorts. We use an empirical knowledge of glass to make beautiful objects – and sometimes even make new discoveries

Like other “glass artists”, I am an experimentalist of sorts. We use an empirical knowledge of glass to make beautiful objects – and sometimes even make new discoveries. In fact, some historians say that hydrofluoric acid was first created in 1670 by a German glassworker named Heinrich Schwanhardt.

While treating a mineral called fluorspar with acid, he saw that the lenses in his spectacles went cloudy – prompting him to start using the same reaction to etch glass. Only much later – in the late 18th century – did chemists carry out “proper” lab experiments to show that fluorspar (calcium fluoride) reacts with the acid to create what we now call hydrofluoric acid.

From the 19th century onwards, acid-etching techniques started to be used by numerous stained-glass artists and studios throughout Britain and Ireland. Dublin-born Harry Clarke (1889–1931) was the leading proponent of the hydrofluoric acid-etching technique, which he mastered in an exceptionally personal and imaginative manner.

Art of glass

I first came across acid etching in 2010 while studying glass and architecture at Central Saint Martins, which is part of the University of the Arts London. The technique intrigued me and I started wondering about its origins and how it works, from a scientific point of view. What chemical processes are involved? What happens if you vary how the acid is applied? And how can that create new decorative effects?

A glass artwork in a large gallery space with light shining through and reflecting colours on the floor

Unable to find full answers to my questions, I started carrying out my own experiments and investigations. I wanted to understand how fluorspar – which can be colourless, deep green or even purple – can be turned into hydrofluoric acid and what goes on at a chemical level when it etches glass.

During my investigations, which I published in 2014 in The Journal of Stained Glass (38 146), I was astonished to find references to glass in the famous lectures given by Richard Feynman about quantum electrodynamics. Published in book form as QED: the Strange Theory of Light and Matter, Feynman explained the partial reflection of light by experimenting with blocks of glass.

He showed that the amount of light reflected increases with the thickness of the glass, pointing out that photons interact with electrons throughout the material, not just on the surface. “A piece of glass,” Feynman wrote, “is a terrible monster of complexity – huge numbers of electrons are jiggling about.”

In my own work, I’ve recently been experimenting with glass of different thickness to make a piece of art inspired by the packaging for a quantum chip made by Rigetti Computing. Entitled Per scientiam ad astra (through science to the stars), the artwork was displayed at the 2024 British Glass Biennale at the Ruskin Glass Centre in Stourbridge, UK – a historically significant area for glass-making that pioneered the creation of etched glass in the 19th century.

Rigetti Computing’s quantum chip

A quantum computer and a macro shot of the container for the microchip

The quantum computers developed by US firm Rigetti Computing are based on superconducting qubits made from materials such as aluminium, indium and niobium. The qubits are manufactured using a mix of novel fabrication methods and well-established semiconductor and micro-electromechanical systems (MEMS) processing techniques. The quantum chip – containing the qubits and other components such as readout resonators – are carefully assembled inside a gold-plated copper packaging that connects it to a printed circuit board (PCB).

The PCB in turn routes the signals to microwave connectors, with the whole system cooled to below 10 millikelvin using dilution refrigeration. The environment in which the quantum bits operate is carefully engineered so that they don’t lose their coherence. Rigetti’s design could, in principle, be scaled up to create much larger and more reliable quantum processors with many more qubits.

The packaging for the quantum chip, on which Oksana Kondratyeva’s artwork is based, is a disc 81.5 mm in diameter and 12 mm deep (see image). With the chip at its centre, the packaging is mounted at the bottom of a tower-like structure that, along with the rest of the fridge and wiring, forms the fully assembled quantum computer. Signals are delivered to and from the chip to drive qubit operations and return measured results.

A quantum rose

Creating an artwork based on quantum technology might be an unusual thing to do, but when I saw a photo of the packaging for a quantum chip back in 2020, I was astounded by the elegant geometry of this enigmatic object, which holds the “brain” of the company’s quantum computer (see box above). Reminding me of the beautiful circular rose windows of medieval cathedrals, I wanted to use glass to create a “quantum rose” for the 21st century. Later, Rigetti got in touch with me after my plans were reported on in Physics World in June 2022.

Two photos: small detail of blue stained glass; full glass artwork covered with lines and arrows drawn in pen

As you can imagine, hydrofluoric acid etching is an extremely dangerous technique, given how corrosive the liquid is. I acid-etch glass from the German company LambertsGlas in a specially equipped studio with a ventilation cabinet to extract fumes and I wear a protective suit with a respiratory mask. As you can see from the video below, I look more like an astronaut than an artist.

Acid etching can be done in lots of different ways (see Materials Today Proceedings 55 56) – but I prefer to apply the acid freely with a cotton or plastic brush, coining my technique “acid painting”. The resulting artwork, which took me several months to make, is just over a metre in diameter.

  • This video has no voice over.     (Video courtesy: Space Production)

Mostly blue with a red focal point, the artwork constantly changes as you move around it. Visitors to the British Glass Biennale seemed to be attracted to it, with comments such as “empowering” and “ethereal”. Per scientiam ad astra will now move to a private residence that just happens to be not far from the UK’s National Quantum Computing Centre in Oxfordshire, where one of Rigetti’s quantum computers is housed.

Art–science crossover

Stained-glass windows were once “illuminated books” for people who could not read – mysterious transmitters of knowledge that told stories about human life. The same, in a way, is true of quantum computers, which are broadening our understanding of reality. And just as mathematical equations can have an inner beauty, so too do quantum computers through the myriad technological innovations that underpin them.

With 2025 being the International Year of Quantum Science and Technology, I hope my artwork raises interesting questions at the intersection between art and science, continuing the “two-cultures” dialogue introduced by C P Snow in 1959. Is it a metaphorical window into the secret architecture of the universe? Or is it a visualization of our reality, where Newtonian and quantum-mechanical worlds merge?

Working with stained glass requires an understanding of how materials behave but that knowledge will only get you so far. To reveal new regions of reality and its beauty, unexpectedness plays a role too. Stained-glass art is the convergence of certainty and uncertainty, where science and art come together. Art can unite people; and through the beauty in art, we can create a better reality.

This article forms part of Physics World‘s contribution to the 2025 International Year of Quantum Science and Technology (IYQ), which aims to raise global awareness of quantum physics and its applications.

Stayed tuned to Physics World and our international partners throughout the next 12 months for more coverage of the IYQ.

Find out more on our quantum channel.

Nuclear shape transitions visualized for the first time

Diagram showing a xenon atom changing shape from spherical to prolate to triaxial to oblate during a collision at the LHC

Xenon nuclei change shape as they collide, transforming from soft, oval-shaped particles to rigid, spherical ones. This finding, which is based on simulations of experiments at CERN’s Large Hadron Collider (LHC), provides a first look at how the shapes of atomic nuclei respond to extreme conditions. While the technique is still at the theoretical stage, physicists at the Niels Bohr Institute (NBI) in Denmark and Peking University in China say that ultra-relativistic nuclear collisions at the LHC could allow for the first experimental observations of these so-called nuclear shape phase transitions.

The nucleus of an atom is made up of protons and neutrons, which are collectively known as nucleons. Like electrons, nucleons exist in different energy levels, or shells. To minimize the energy of the system, these shells take different shapes, with possibilities including pear, spherical, oval or peanut-shell-like formations. These shapes affect many properties of the atomic nucleus as well as nuclear processes such as the strong interactions between protons and neutrons. Being able to identify them is thus very useful for predicting how nuclei will behave.

Colliding pairs of 129Xe atoms at the LHC

In the new work, a team led by You Zhou at the NBI and Huichao Song at Peking University studied xenon-129 (129Xe). This isotope has 54 protons and 75 neutrons and is considered a relatively large atom, making its nuclear shape easier, in principle, to study than that of smaller atoms.

Usually, the nucleus of xenon-129 is oval-shaped (technically, it is a 𝛾-soft rotor). However, low-energy nuclear theory predicts that it can transition to a spherical, prolate or oblate shape under certain conditions. “We propose that to probe this change (called a shape phase transition), we could collide pairs of 129Xe atoms at the LHC and use the information we obtain to extract the geometry and shape of the initial colliding nuclei,” Zhou explains. “Probing these initial conditions would then reveal the shape of the 129Xe atoms after they had collided.”

A quark-gluon plasma

To test the viability of such experiments, the researchers simulated accelerating atoms to near relativistic speeds, equivalent to the energies involved in a typical particle-physics experiment at the LHC. At these energies, when nuclei collide with each other, their constituent protons and neutrons break down into smaller particles. These smaller particles are mainly quarks and gluons, and together they form a quark-gluon plasma, which is a liquid with virtually no viscosity.

Zhou, Song and colleagues modelled the properties of this “almost perfect” liquid using an advanced hydrodynamic model they developed called IBBE-VISHNU. According to these analyses, the Xe nuclei go from being soft and oval-shaped to rigid and spherical as they collide.

Studying shape transitions was not initially part of the researchers’ plan. The original aim of their work was to study conditions that prevailed in the first 10-6 seconds after the Big Bang, when the very early universe is thought to have been filled with a quark-gluon plasma of the type produced at the LHC. But after they realized that their simulations could shed light on a different topic, they shifted course.

“Our new study was initiated to address the open question of how nuclear shape transitions manifest in high-energy collisions,” Zhou explains, “and we also wanted to provide experimental insights into existing theoretical nuclear structure predictions.”

One of the team’s greatest difficulties lay in developing the complex models required to account for nuclear deformation and probe the structure of xenon and its fluctuations, Zhou tells Physics World. “There was also a need for compelling new observables that allow for a direct probe of the shape of the colliding nuclei,” he says.

Applications in both high- and low-energy nuclear and structure physics

The work could advance our understanding of fundamental nuclear properties and the operation of the theory of quantum chromodynamics (QCD) under extreme conditions, Zhou adds. “The insights gleaned from this work could guide future nuclear collision experiments and influence our understanding of nuclear phase transitions, with applications extending to both high-energy nuclear physics and low-energy nuclear structure physics,” he says.

The NBI/Peking University researchers say that future experiments could validate the nuclear shape phase transitions they observed in their simulations. Expanding the study to other nuclei that could be collided at the LHC is also on the cards, says Zhou. “This could deepen our understanding of nuclear structure at ultra-short timescales of 10-24 seconds.”

The research is published in Physical Review Letters.

From qubits to metamaterials: tech that led to Institute of Physics business awards 2024

I have mentioned many times in this column the value of the business awards given by the Institute of Physics (IOP), which can be a real “stamp of approval” for firms developing new technology. Having helped to select the 2024 winners, it was great to see eight companies winning a main IOP Business Innovation Award this time round, bringing the total number of firms honoured over the last 13 years to 86. Some have won awards on more than one occasion, with Fetu being one of the latest to join this elite group.

Set up by Jonathan Fenton in 2016, FeTu originally won an IOP Business Start-up Award in 2020 for its innovative Fenton Turbine. According to Fenton, who is chief executive, it is the closest we have ever got to the ideal, closed-cycle reversible heat engine first imagined by thermodynamics pioneer Nicolas Carnot in 1824. The turbine, the firm claims, could replace compressors, air conditioners, fridges, vacuum pumps and heat pumps with efficiency savings across the board.

Back in 2020, it might have sounded like a “too-good-to-be-true” technology, but Fenton has sensibly set out to prove that’s not the case, with some remarkable results. The turbine is complex to describe but the first version promised to cut the energy cost of compressing gases like air by 25%. They claim has already been proven in independent tests carried out by researchers at the University of Bath.

One challenge of any technology with many different applications is picking which to focus on first

One challenge of any technology with many different applications is picking which to focus on first. Having decided to focus on a couple of unique selling factors in large markets, FeTu has now won a 2024 Business Innovation Award for developing a revolutionary heat engine that can generate electrical power from waste heat and geothermal sources as low as 40 °C. It has a huge market potential as it is currently not possible to do this economically.

Innovative ideas

Another winner of an IOP Business Innovation Award is Oxford Ionics,  a quantum-computing firm set up in 2019 by Chris Balance and Tom Harty after doing PhDs at the University of Oxford. Their firm’s qubits are based on trapped ions, which traditionally have been controlled with lasers. It’s an approach that works well for small processors, but becomes untenable and error-prone as the size of the processor scales, and the number of qubits increases.

Instead of lasers, Oxford Ionics’ trapped-ion processors use a proprietary, patented electronic system to control the qubits. It was for this system that the company was recognized by the IOP, along with its ability to scale the architecture so that the chips can be made in large quantities on standard semiconductor production lines. That’s essential if we are to build practical quantum computers.

While it’s still early days in the commercialisation of quantum computing, Oxford Ionics is an exciting company to watch. It has already won contracts to supply the UK’s National Quantum Computing Centre at Harwell and has bagged a large contract with its partner Infineon Technologies AG in Munich to build a state-of-the-art portable quantum computer for Germany’s cybersecurity innovation agency. The two firms are one of three independent contractors selected by the agency, which is investing a total of €35m in the project.

I should also mention Dublin-based Equal1, which won the IOP’s £10,000 quantum Business Innovation and Growth (qBIG) Prize in 2024. Equal1 is developing rack-mountable quantum computers powered by a system that integrates quantum and classical components onto a single silicon chip using commercial fabrication processes. The company, which aims to develop compact quantum computers, also won 10 months of mentoring from the award’s sponsors Quantum Exponential.

Meanwhile, Covesion – a photonics and quantum components supplier founded in 2009 – has won an IOP Business Innovation Award for its magnesium-doped, periodically poled, lithium niobate (MgO:PPLN) crystals and waveguides. They allow light to be easily converted from one frequency to another, providing access to wavelengths that are not available from commercial laser sources.

With a manufacturing base in Southampton, Covesion works with customers and industry partners to help them design and make high quality MgO:PPLN products used in a wide range of applications. They include quantum computing, communication, sensing and timing; frequency doubling of femtosecond lasers; mid-infrared generation; atom cooling; terahertz generation and biomedical imaging. The shear breadth and global nature of the customer base is impressive.

Sounds promising

Among the companies to win an IOP Business Start-up Award is Metasonixx, based in Brighton. Spun off from the universities of Bristol and Sussex in 2019, the firm makes mass-produced acoustic metamaterial panels, which can dramatically attenuate sound (10 dB in its Sonoblind) and yet still allow air to flow freely (3 dB or 50% attenuation). That might seem counter-intuitive, but that’s where the innovation comes in and the panels can help with noise management and ventilation, allowing industrial ventilators and heat pumps to be more widely used.

Metasonixx Sonoblind Air

The company really got going in 2020, when it got a grant from UK Research and Innovation to see if its metamaterials could cut noise in hospitals to help patients recovering from COVID-19 and improve the well-being of staff. After Metasonixx won the Armourers and Brasiers Venture Prize in 2021 for their successes on COVID wards, the firm decided to mass-produce panels that could perform as well as traditional noise-reduction solutions but are modular and greener, with one-third of the mass and occupying one-twelfth of the space.

From a physics point of view, panels that can let air and light through in this way are interferential filters, but working over four doublings of frequency (or octaves). With manufacturing and first sales in 2023, their desk separators are now being tested in noisy offices worldwide. Metasonixx believes its products, which allow air to flow through them, could help to boost the use of industrial ventilators and heat pumps, thereby helping in the quest to meet net-zero targets.

Winning awards for Metasonixx is not a new experience, having also picked up a “Seal of Excellence Award” from the European Commission in 2023 and honoured at Bristol’s Tech-Xpo in 2024. Its new IOP award will sit very nicely in this innovative company’s trophy cabinet.

  • In his next article, James McKenzie will look at the rest of the 2024 IOP Business Award winners in imaging and medical technology.

Physicists close in on fractionally-charged electron mystery in graphene

Physicists in the US have found an explanation for why electrons in a material called pentalayer moiré graphene carry fractional charges even in the absence of a magnetic field. This phenomenon is known as the fractional quantum anomalous Hall effect, and teams at the Massachusetts Institute of Technology (MIT), Johns Hopkins University and Harvard University/University of California, Berkeley have independently suggested that an interaction-induced topological “flat” band in the material’s electronic structure may be responsible.

Scientists already knew that electrons in graphene could, in effect, split into fractions of themselves in the presence of a very strong magnetic field. This is an example of the fractional quantum Hall effect, which occurs when a material’s Hall conductance is quantized at fractional multiples of e2/h.

In 2023, several teams of researchers introduced a new twist by observing this fractional quantization even without a magnetic field. The fractional quantum anomalous Hall effect, as it was dubbed, was initially observed in material called twisted molybdenum ditelluride (MoTe2).

Then, in February this year, an MIT team led by physicist Long Ju spotted the same effect in pentalayer moiré graphene. This material consists of a layer of a two-dimensional hexagonal boron nitride (hBN) with five layers of graphene (carbon sheets just one atom thick) stacked on top of it. The graphene and hBN layers are twisted at a small angle with respect to each other, resulting in a moiré pattern that can induce conflicting properties such as superconductivity and insulating behaviour within the structure.

Answering questions

Although Ju and colleagues were the first to observe the fractional quantum anomalous Hall effect in graphene, their paper did not explain why it occurred. In the latest group of studies, other scientists have put forward a possible solution to the mystery.

According to MIT’s Senthil Todadri, the effect could stem from the fact that electrons in two-dimensional materials like graphene are confined in such small spaces that they start interacting strongly. This means that they can no longer be considered as independent charges that naturally repel each other. The Johns Hopkins team led by Ya-Hui Zhang and the Harvard/Berkeley team led by Ashvin Vishwanath and Daniel E Parker came to similar conclusions, and published their work in Physical Review Letters alongside that of the MIT team.

Crystal-like periodic patterns form an electronic “flat” band

Todadri and colleagues started their analyses with a reasonably realistic model of the pentalayer graphene. This model treats the inter-electron Coulomb repulsion in an approximate way, replacing the “push” of all the other electrons on any given electron with a single potential, Todadri explains. “Such a strategy is routinely employed in quantum mechanical calculations of, say, the structure of atoms, molecules or solids,” he notes.

The MIT physicists found that the moiré arrangement of pentalayer graphene induces a weak electron potential that forces electrons passing through it to arrange themselves in crystal-like periodic patterns that form a “flat” electronic band. This band is absent in calculations that do not account for electron–electron interactions, they say.

Such flat bands are especially interesting because electrons in them become “dispersionless” – that is, their kinetic energy is suppressed. As the electrons slow almost to a halt, their effective mass approaches infinity, leading to exotic topological phenomena as well as strongly correlated states of matter associated with high-temperature superconductivity and magnetism. Other quantum properties of solids such as fractional splitting of electrons can also occur.

“Mountain and valley” landscapes

So what causes the topological flat band in pentalayer graphene to form? The answer lies in the “mountain and valley” landscapes that naturally appear in the electronic crystal. Electrons in this material experience these landscapes as pseudo-magnetic fields, which affect their motion and, in effect, do away with the need to apply a real magnetic field to induce the fractional Hall quantization.

“This interaction-induced topological (‘valley-polarized Chern-1’) band is also predicted by our theory to occur in the four- and six-layer versions of multilayer graphene,” Todadri says. “These structures may then be expected to host phases where electron fractions appear.”

In this study, the MIT team presented only a crude treatment of the fractional states. Future work, Todadri says, may focus on understanding the precise role of the moiré potential produced by aligning the graphene with a substrate. One possibility, he suggests, is that it simply pins the topological electron crystal in place. However, it could also stabilize the crystal by tipping its energy to be lower than a competing liquid state. Another open question is whether these fractional electron phenomena at zero magnetic field require a periodic potential in the first place. “The important next question is to develop a better theoretical understanding of these states,” Todadri tells Physics World.

Return to Helgoland: celebrating 100 years of quantum mechanics

Sunset on the island of Helgoland

At 3 a.m. one morning in June 1925, an exhausted, allergy-ridden 23-year old climbed a rock at the edge of a small island off the coast of Germany in the North Sea. Werner Heisenberg, who was an unknown physics postdoc at the time, had just cobbled together, in crude and unfamiliar mathematics, a framework that would shortly become what we know as “matrix mechanics”. If we insist on pegging the birth of quantum mechanics to a particular place and time, Helgoland in June 1925 it is.

Heisenberg’s work a century ago is the reason why the United Nations has proclaimed 2025 to be the International Year of Quantum Science and Technology. It’s a global initiative to raise the public’s awareness of quantum science and its applications, with numerous activities in the works throughout the year. One of the most significant events for physicists will be a workshop running from 9–14 June on Helgoland, exactly 100 years on from the very place where quantum mechanics supposedly began.

Entitled “Helgoland 2025”, the event is designed to honour Heisenberg’s development of matrix mechanics, which organizers have dubbed “the first formulation of quantum theory”. The workshop, they say, will explore “the increasingly fruitful intersection between the foundations of quantum mechanics and the application of these foundations in real-world settings”. But why was Heisenberg’s work so vital to the development of quantum mechanics? Was it really as definitive as we like to think? And is the oft-repeated Helgoland story really true?

How it all began

The events leading up to Heisenberg’s trip can be traced back to the work of Max Planck in 1900. Planck was trying to produce a formula for how certain kinds of materials absorb and emit light depending on energy. In what he later referred to as an “act of sheer desperation”, Planck found himself having to use the idea of the “quantum”, which implied that electromagnetic radiation is not continuous but can be absorbed and emitted only in discrete chunks.

Standing out as a smudge on the beautiful design of classical physics, the idea of quantization appeared of limited use. Some physicists called it “ugly”, “grotesque” and “distasteful”; it was surely a theoretical sticking plaster that could soon be peeled off. But the quantum proved indispensable, cropping up in more and more branches of physics, including the structure of the hydrogen atom, thermodynamics and solid-state physics. It was like an obnoxious visitor whom you try to expel from your house but can’t. Worse, its presence seemed to grow. The quantum, remarked one scientist at the time, was a “lusty infant”.

‘Quantum theory’ was like having instructions for how to get from place A to place B. What you really wanted was a ‘quantum mechanics’ – a map that showed you how to go from any place to any other.

Robert P Crease, Stony Brook University

Attempts to domesticate that infant in the first quarter of the 20th century were made not only by Planck but other physicists too, such as Wolfgang Pauli, Max Born, Niels Bohr and Ralph Kronig. They succeeded only in producing rules for calculating certain phenomena that started with classical theory and imposed conditions. “Quantum theory” was like having instructions for how to get from place A to place B. What you really wanted was a “quantum mechanics” – a map that, working with one set of rules, showed you how to go from any place to any other.

Werner Heisenberg (1901-1976). Portrait of the German theoretical physicist, c.1927.

Heisenberg was a young crusader in this effort. Born on 5 December 1901 – the year after Planck’s revolutionary discovery – Heisenberg had the character often associated with artists, with dashing looks, good musicianship and a physical frailty including a severe vulnerability to allergies. That summer in 1923, Heisenberg had just finished his PhD under Arnold Sommerfeld at the Ludwig Maximilian University in Munich and was starting a postdoc with Born at the University of Göttingen.

Like others, Heisenberg was stymied in his attempts to develop a mathematical framework for the frequencies, amplitudes, orbitals, positions and momenta of quantum phenomena. Maybe, he wondered, the trouble was trying to cast these phenomena in a Newtonian-like visualizable form. Instead of treating them as classical properties with specific values, he decided to look at them in purely mathematical terms as operators acting on functions. It was then that an “unfortunate personal setback” occurred.

Destination Helgoland

Referring to a bout of hay fever that had wiped him out, Heisenberg asked Born for a two-week leave of absence from Göttingen and took a boat to Helgoland. The island, which lies some 50 km off Germany’s mainland, is barely 1 km2 in size. However, its strategic military location had given it an outsized history that saw it swapped several times between different European powers. Part of Denmark from 1714, the island was occupied by Britain in 1807 before coming under Germany’s control in 1890.

During the First World War, Germany turned the island into a military base and evacuated all its residents. By the time Heisenberg arrived, the soldiers had long gone and Helgoland was starting to recover its reputation as a centre for commercial fishing and a bracing tourist destination. Most importantly for Heisenberg, it had fresh winds and was remote from allergen producers.

Colourful lobster huts on the offshore island Helgoland

Heisenberg arrived at Helgoland on Saturday 6 June 1925 coughing and sneezing, and with such a swollen face that his landlady decided he had been in a fight. She installed him in a quiet room on the second floor of her Gasthaus that overlooked the beach and the North Sea. But he didn’t stop working. “What exactly happened on that barren, grassless island during the next ten days has been the subject of much speculation and no little romanticism,” wrote historian David Cassidy in his definitive 1992 book Uncertainty: The Life and Science of Werner Heisenberg.

In Heisenberg’s telling, decades later, he kept turning over all he knew and began to construct equations of observables – of frequencies and amplitudes – in what he called “quantum-mechanical series”. He outlined a rough mathematical scheme, but one so awkward and clumsy that he wasn’t even sure it obeyed the conservation of energy, as it surely must. One night Heisenberg turned to that issue.

“When the first terms seemed to accord with the energy principle, I became rather excited,” he wrote much later in his 1971 book Physics and Beyond. But he was still so tired that he began to stumble over the maths. “As a result, it was almost three o’clock in the morning before the final result of my computations lay before me.” The work still seemed finished yet incomplete – it succeeded in giving him a glimpse of a new world though not one worked out in detail – but his emotions were weighted with fear and longing.

“I was deeply alarmed,” Heisenberg continued. “I had the feeling that, through the surface of atomic phenomena, I was looking at a strangely beautiful interior, and felt almost giddy at the thought that I now had to probe this wealth of mathematical structure nature had so generously spread out before me. I was far too excited to sleep and so, as a new day dawned, I made for the southern tip of the island, where I had been longing to climb a rock jutting out into the sea. I now did so without too much trouble, and waited for the sun to rise.”

What happened on Helgoland?

Historians are suspicious of Heisenberg’s account. In their 2023 book Constructing Quantum Mechanics Volume 2: The Arch 1923–1927, Anthony Duncan and Michel Janssen suggest that Heisenberg made “somewhat less progress in his visit to Helgoland in June 1925 than later hagiographical accounts of this episode claim”. They believe that Heisenberg, in Physics and Beyond, may “have misremembered exactly how much he accomplished in Helgoland four decades earlier”.

What’s more – as Cassidy wondered in Uncertainty – how could Heisenberg have been so sure that the result agreed with the conservation of energy without having carted all his reference books along to the island, which he surely had not. Could it really be, Cassidy speculated sceptically, that Heisenberg had memorized the relevant data?

Alexei Kojevnikov – another historian – even doubts that Heisenberg was entirely candid about the reasons behind his inspiration. In his 2020 book The Copenhagen Network: The Birth of Quantum Mechanics from a Postdoctoral Perspective, Kojevnikov notes that fleeing from strong-willed mentors such as Bohr, Born, Kronig, Pauli and Sommerfeld was key to Heisenberg’s creativity. “In order to accomplish his most daring intellectual breakthrough,” Kojevnikov writes, “Heisenberg had to escape from the authority of his academic supervisors into the temporary loneliness and freedom on a small island in the North Sea.”

Whatever did occur on the island, one thing is clear. “Heisenberg had his breakthrough,” decides Cassidy in his book. He left Helgoland 10 days after he arrived, returned to Göttingen, and dashed off a paper that was published in Zeitschrift für Physik in September 1925 (33 879). In the article, Heisenberg wrote that “it is not possible to assign a point in space that is a function of time to an electron by means of observable quantities.” He then suggested that “it seems more advisable to give up completely on any hope of an observation of the hitherto-unobservable quantities (such as the position and orbital period of the electron).”

To modern ears, Heisenberg’s comments may seem unremarkable. But his proposition certainly would have been nearly unthinkable to those steeped in Newtonian mechanics. Of course, the idea of completely abandoning the observability of those quantities wasn’t quite true. Under certain conditions, it can make sense to speak of observing them. But they certainly captured the direction he was taking.

The only trouble was that his scheme, with its “quantum-mechanical relations”, produced formulae that were “noncommutative” – a distressing asymmetry that was surely an incorrect feature in a physical theory. Heisenberg all but shoved this feature under the rug in his Zeitschrift für Physik article, where he relegated the point to a single sentence.

Abstract image of quantum ideas

The more mathematically trained Born, on the other hand, sensed something familiar about the maths and soon recognized that Heisenberg’s bizarre “quantum-mechanical relations” with their strange tables were what mathematicians called matrices. Heisenberg was unhappy with that particular name for his work, and considered returning to what he had called “quantum-mechanical series”.

Fortunately, he didn’t, for it would have made the rationale for the Helgoland 2025 conference clunkier to describe. Born was delighted with the connection to traditional mathematics. In particular he found that when the matrix associated with momentum and the matrix q associated with position are multiplied in different orders, the difference between them is proportional to Planck’s constant, h.

As Born wrote in his 1956 book Physics in My Generation: “I shall never forget the thrill I experienced when I succeeded in condensing Heisenberg’s ideas on quantum conditions in the mysterious equation pqqp = h/2πi, which is the centre of the new mechanics and was later found to imply the uncertainty relations”. In February 1926, Born, Heisenberg and Jordan published a landmark paper that worked out the implications of this equation (Zeit. Phys. 35 557). At last, physicists had a map of the quantum domain.

Almost four decades later in an interview with the historian Thomas Kuhn, Heisenberg recalled Pauli’s “extremely enthusiastic” reaction to the developments. “[Pauli] said something like ‘Morgenröte einer Neuzeit’,” Heisenberg told Kuhn. “The dawn of a new era.” But it wasn’t entirely smooth sailing after that dawn. Some physicists were unenthusiastic about Heisenberg’s new mechanics, while others were outright sceptical.

Werner Heisenberg and Erwin Schrödinger

Yet successful applications kept coming. Pauli applied the equation to light emitted by the hydrogen atom and derived the Balmer formula, a rule that had been known empirically since the mid-1880s. Then, in one of the most startling coincidences in the history of science, the Austrian physicist Erwin Schrödinger produced a complete map of the quantum domain stemming from a much more familiar mathematical basis called “wave mechanics”. Crucially, Heisenberg’s matrix mechanics and Schrödinger’s maps turned out to be identical.

Even more fundamental implications followed. In an article published in Naturwissenschaften (14 899) in September 1926, Heisenberg wrote that our “ordinary intuition” does not work in the subatomic realm. “Because the electron and the atom possess not any degree of physical reality as the objects of our daily experience,” he said, “investigation of the type of physical reality which is proper to electrons and atoms is precisely the subject of quantum mechanics.”

Quantum mechanics, alarmingly, was upending reality itself, for the uncertainty it introduced was not only mathematical but “ontological” – meaning it had to do with the fundamental features of the universe. Early the next year, Heisenberg, in correspondence with Pauli, derived the equation Δp Δq ≥ h/4π, the “uncertainty principle”, which became the touchstone of quantum mechanics. The birth complications, however, persisted. Some even got worse.

Catalytic conference

A century on from Heisenberg’s visit to Helgoland, quantum mechanics still has physicists scratching their heads. “I think most people agree that we are still trying to make sense of even basic non-relativistic quantum mechanics,” admits Jack Harris, a quantum physicist at Yale University who is co-organizing Helgoland 2025 with Časlav Brukner, Steven Girvin and Florian Marquardt.

We really don’t fully understand the quantum world yet. We apply it, we generalize it, we develop quantum field theories and so on, but still a lot of it is uncharted territory.

Igor Pikovsky, Stevens Institute, New Jersey

“We really don’t fully understand the quantum world yet,” adds Igor Pikovsky from the Stevens Institute in New Jersey, who works in gravitational phenomena and quantum optics. “We apply it, we generalize it, we develop quantum field theories and so on, but still a lot of it is uncharted territory.” Philosophers and quantum physicists with strong opinions have debated interpretations and foundational issues for a long time, he points out, but the results of those discussions have been unclear.

Helgoland 2025 hopes to change all that. Advances in experimental techniques let us ask new kinds of fundamental questions about quantum mechanics. “You have new opportunities for studying quantum physics at completely different scales,” says Pikovsky. “You can make macroscopic, Schrödinger-cat-like systems, or very massive quantum systems to test. You don’t need to debate philosophically about whether there’s a measurement problem or a classical-quantum barrier – you can start studying these questions experimentally.”

One phenomenon fundamental to the puzzle of quantum mechanics is entanglement, which prevents the quantum state of a system from being described independently of the state of others. Thanks to the Einstein–Podolsky–Rosen (EPR) paper of 1935 (Phys. Rev. 47 777), Chien-Shiung Wu and Irving Shaknov’s experimental demonstration of entanglement in extended systems in 1949, and John Bell’s theorem in 1964 (Physics 1 195), physicists know that entanglement in extended systems is a large part of what’s so weird about quantum mechanics.

Understanding all that entanglement entails, in turn, has led physicists to realize that information is a fundamental physical concept in quantum mechanics. “Even a basic physical quantum system behaves differently depending on how information about it is stored in other systems,” Harris says. “That’s a starting point both for deep insights into what quantum mechanics tells us about the world, and also for applying it.”

Helgoland 2025: have you packed your tent?

Red and white striped lighthouse on sand dunes at coast of island

Running from 9–14 June 2025 on the island where Werner Heisenberg did his pioneering work on quantum mechanics, the Helgoland 2025 workshop is a who’s who of quantum physics. Five Nobel laureates in the field of quantum foundations are coming. David Wineland and Serge Haroche, who won in 2012 for measuring and manipulating individual quantum systems, will be there. So too will Alain Aspect, John Clauser and Anton Zeilinger, who were honoured in 2022 for their work on quantum-information science.

There’ll be Charles Bennett and Gilles Brassard, who pioneered quantum cryptography, quantum teleportation and other applications, as well quantum-sensing guru Carlton Caves. Researchers from industry are intending to be present, including Krysta Svore, who’s vice-president of Microsoft Quantum.

Other attendees are from the intersection of foundations and applications. There will be researchers working on gravitation, mostly from quantum gravity phenomenology, where the aim is to seek experimental signatures of the effect. Others work on quantum clocks, quantum cryptography, and innovative ways of controlling light, such as using squeezed light at LIGO, to detect gravitational waves.

Helgoland speakers

The programme starts in Hamburg on 9 June with a banquet and a few talks. Attendees will then take a ferry to Helgoland the following morning for a week of lectures, panel discussions and poster sessions. All talks are plenary, but in the evenings panels of a half-dozen or so people will address bigger questions familiar to every quantum physicist but rarely discussed in research papers. What is it about quantum mechanics, for instance, that makes it so compatible with so many interpretations?

If you’re thinking of going, you’re almost certainly out of luck. Registration closed in April 2024, while hotels, Airbnb and Booking.com venues are nearly exhausted. Participants are having to share double rooms or invited to camp on the beaches – with their own gear.

Helgoland 2025 will therefore focus on the two-way street between foundations and applications in what promises to be a unique event. “The conference is intended to be a bit catalytic,” Harris adds. “[There will be] people who didn’t realize that others were working on similar issues in different fields, and a lot of people who will never have met each other”. The disciplinary diversity will be augmented by the presence of students as well as poster sessions, which tend to bring in an even broader variety of research topics.

There will be people [at Helgoland] who work on black holes whose work is familiar to me but who I haven’t met yet.

Ana Maria Rey, University of Colorado, Boulder

One of those looking forward to such encounters is Ana Maria Rey – a theoretical physicist at the University of Colorado, Boulder, and a JILA fellow who studies quantum phenomena in ways that have improved atomic clocks and quantum computing. “There will be people who work on black holes whose work is familiar to me but who I haven’t met yet,” she says. Finding people should be easy: Helgoland is tiny and only a hand-picked group of people have been invited to attend (see box above).

What’s also unusual about Helgoland is that it has as many practically-minded as theoretically-minded participants. But that doesn’t faze Magdalena Zych, a physicist from Stockholm University in Sweden. “I’m biased because academically I grew up in Vienna, where Anton Zeilinger’s group always had people working on theory and applications,” she says.

Zych’s group has, for example, recently discovered a way to use the uncertainty principle to get a better understanding of the semi-classical space–time trajectories of composite particles. She plans to talk about this research at Helgoland, finding it appropriate given that it relies on Heisenberg’s principle, is a product of specific theoretical work and is valid more generally. “It relates to the arch of the conference, looking both backwards and forwards, and from theory to applications.”

Nathalie de Leon: heading for Helgoland

Nathalie de Leon

In June 2022, Nathalie de Leon, a physicist at Princeton University working on quantum computing and quantum metrology, was startled to receive an invitation to the Helgoland conference. “It’s not often you get [one] a full three years in advance,” says de Leon, who also found it unusual that participants had to attend for the entire six days. But she was not surprised at the composition of the conference with its mix of theorists, experimentalists and people applying what she calls the “weirder” aspects of quantum theory.

“When I was a graduate student [in the late 2000s], it was still the case that quantum theorists and researchers who built things like quantum computers were well aware of each other but they didn’t talk to each other much,” she recalls. “In their grant proposals, the physicists had to show they knew what the computer scientists were doing, and the computer scientists had to justify their work with appeals to physics. But they didn’t often collaborate.” De Leon points out that over the last five or 10 years, however, more and more opportunities for these groups to collaborate have emerged. “Companies like IBM, Google, QuEra and Quantinuum now have theorists and academics trying to develop the hardware to make quantum tech a practical reality,” she says.

Some quantum applications have even cropped up in highly sophisticated technical devices, such as the huge Laser Interferometer Gravitational Wave Observatory (LIGO). “A crazy amount of classical engineering was used to build this giant interferometer,” says de Leon, “which got all the way down to a minuscule sensitivity. Then as a last step the scientists injected something called squeezed light, which is a direct consequence of quantum mechanics and quantum measurement.” According to de Leon, that squeezing let us see something like eight times more of the universe. “It’s one of the few places where we get a real tangible advantage out of the strangeness of quantum mechanics,” she adds.

Other, more practical benefits are also bound to emerge from quantum information theory and quantum measurement. “We don’t yet have quantum technologies on the open consumer market in the same way we have lasers you can buy on Amazon for $15,” de Leon says. But groups gathering in Helgoland will give us a better sense of where everything is heading. “Things,” she adds, “are moving so fast.”

Sadly, participants will not be able to visit Heisenberg’s Gasthaus, nor any other building where he might have been. During the Second World War, Germany again relocated Helgoland’s inhabitants and turned the island into a military base. After the war, the Allies piled up unexploded ordinances on the island and set them off, in what is said to be one of the biggest conventional explosions in history. The razed homeland was then given back to its inhabitants.

We will not be 300 Heisenbergs going for hikes. [Attendees] certainly won’t be trying to get away from each other.

Jack Harris, Yale University

Helgoland still has rocky outcroppings at its southern end, one of which may or may not be the site of Heisenberg’s early morning climb and vision. But despite the powerful mythology of his story, participants at Helgoland 2025 are not being asked to herald another dawn. “We will not,” says Harris, “be 300 Heisenbergs going for hikes. We certainly won’t be trying to get away from each other.”

The historian of science Mario Biagioli once wrote an article entitled “The scientific revolution is undead”, underlining how arbitrary it is to pin key developments in science – no matter how influential or long-lasting – to specific beginnings and endings, for each new generation of scientists finds ever more to mine in the radical discoveries of predecessors. With so many people working on so many foundational issues set to be at Helgoland 2025, new light is bound to emerge. A century on, the quantum revolution is alive and well.

This article forms part of Physics World‘s contribution to the 2025 International Year of Quantum Science and Technology (IYQ), which aims to raise global awareness of quantum physics and its applications.

Stayed tuned to Physics World and our international partners throughout the next 12 months for more coverage of the IYQ.

Find out more on our quantum channel.

Delayed Big Bang for dark matter could be detected in gravitational waves

New constraints on a theory that says dark matter was created just after the Big Bang  – rather than at the Big Bang – have been determined by Richard Casey and  Cosmin Ilie at Colgate University in the US. The duo calculated the full range of parameters in which a “Dark Big Bang” could fit into the observed history of the universe. They say that evidence of this delayed creation could be found in gravitational waves.

Dark matter is a hypothetical substance that is believed to play an important role in the structure and dynamics of the universe. It appears to account for about 27% of the mass–energy in the cosmos and is part of the Standard Model of cosmology. However, dark matter particles have never been observed directly.

The Standard Model also says that the entire contents of the universe emerged nearly 14 billion years ago in the Big Bang. Yet in 2023, Katherine Freese and Martin Winkler at the University of Texas at Austin introduced a captivating new theory, which suggests that the universe’s dark matter may have been created after the Big Bang.

Evidence comes later on

Freese and Winkler pointed out that presence of photons and normal matter (mostly protons and neutrons) can be inferred from almost immediately after the Big Bang. However, the earliest evidence for dark matter comes from later on, when it began to exert its gravitational influence on normal matter. As a result, the duo proposed that dark matter may have appeared in a second event called the Dark Big Bang.

“In Freese and Winkler’s model, dark matter particles can be produced as late as one month after the birth of our universe,” Ilie explains. “Moreover, dark matter particles produced via a Dark Big Bang do not interact with regular matter except via gravity. Thus, this model could explain why all attempts at detecting dark matter – either directly, indirectly, or via particle production – have failed.”

According to this theory, dark matter particles are generated by a certain type of scalar field. This is an energy field that has a single value at every point in space and time (a familiar example is the field describing gravitational potential energy). Initially, each point of this scalar field would have occupied a local minimum in its energy potential. However, these points could have then transitioned to lower-energy minima via quantum tunnelling. During this transition, the energy difference between the two minima would be released, producing particles of dark matter.

Consistent with observations

Building on this idea, Casey and Ilie looked at how predictions of the Dark Big Bang model could be consistent with astronomers’ observations of the early universe.

“By focusing on the tunnelling potentials that lead to the Dark Big Bang, we were able to exhaust the parameter space of possible cases while still allowing for many different types of dark matter candidates to be produced from this transition,” Casey explains. “Aside from some very generous mass limits, the only major constraint on dark matter in the Dark Big Bang model is that it interacts with everyday particles through gravity alone.” This is encouraging because this limited interaction is what physicists expect of dark matter.

For now, the duo’s results suggest that the Dark Big Bang is far less constrained by past observations than Freese and Winkler originally anticipated. As Ilie explains, their constraints could soon be put to the test.

“We examined two Dark Big Bang scenarios in this newly found parameter space that produce gravitational wave signals in the sensitivity ranges of existing and upcoming surveys,” he says. “In combination with those considered in Freese and Winkler’s paper, these cases could form a benchmark for gravitational wave researchers as they search for evidence of a Dark Big Bang in the early universe.”

Subtle imprint on space–time

If a Dark Big Bang happened, then the gravitational waves it produced would have left a subtle imprint on the fabric of space–time. With this clearer outline of the Dark Big Bang’s parameter space, several soon-to-be active observational programmes will be well equipped to search for these characteristic imprints.

“For certain benchmark scenarios, we show that those gravitational waves could be detected by ongoing or upcoming experiments such as the International Pulsar Timing Array (IPTA) or the Square Kilometre Array Observatory (SKAO). In fact, the evidence of background gravitational waves reported in 2023 by the NANOGrav experiment – part of the IPTA – could be attributed to a Dark Big Bang realization,” Casey says.

If these studies find conclusive evidence for Freese and Winkler’s original theory, Casey and Ilie’s analysis could ultimately bring us a step closer to a breakthrough in our understanding of the ever-elusive origins of dark matter.

The research is described in Physical Review D.

The mechanics of squirting cucumbers revealed

The plant kingdom is full of intriguing ways to distribute seeds such as the dandelion pappus effortlessly drifting on air currents to the ballistic nature of fern sporangia.

Not to be outdone, the squirting cucumber (Ecballium elaterium), which is native to the Mediterranean and is often regarded as a weed, has its own unique way of ejecting seeds.

When ripe, the ovoid-shaped fruits detach from the stem and as it does so explosively ejects seeds in a high-pressure jet of mucilage.

The process, which lasts just 30 milliseconds, launches the seeds at more than 20 metres per second with some landing 10 metres away.

Researchers in the UK have, for the first time, revealed the mechanism behind the squirt by carrying out high-speed videography, computed tomography scans and mathematical modelling.

“The first time we inspected this plant in the Botanic Garden, the seed launch was so fast that we weren’t sure it had happened,” recalls Oxford University mathematical biologist Derek Moulton. “It was very exciting to dig in and uncover the mechanism of this unique plant.”

The researchers found that in the weeks leading up to the ejection, fluid builds up inside the fruits so they become pressurised. Then just before seed dispersal, some of this fluid moves from the fruit to the stem, making it longer and stiffer.

This process crucially causes the fruit to rotate from being vertical to close to an angle of 45 degrees, improving the launch angle for the seeds.

During the first milliseconds of ejection, the tip of the stem holding the fruit then recoils away causing the fruit to counter-rotate and detach. As it does so, the pressure inside the fruit causes the seeds to eject at high speed.

By changing certain parameters in the model, such as the stiffness of the stem, reveals that the mechanism has been fine-tuned to ensure optimal seed dispersal. For example, a thicker or stiffer stem would result in the seeds being launched horizontally and distributed over a narrower area.

According to Manchester University physicist Finn Box, the findings could be used for more effective drug delivery systems “where directional release is crucial”.

From the blackboard to the boardroom: why university is a great place to become an entrepreneur

What does an idea need to change the world? Physics drives scientific advancements in healthcare, green energy, sustainable materials and many other applications. However, to bridge the gap between research and real-world applications, physicists need to be equipped with entrepreneurship skills.

Many students dream of using their knowledge and passion for physics to change the world, but when it comes to developing your own product, it can be hard to know where to start. That’s where my job comes in – I have been teaching scientists and engineers entrepreneurship for more than 20 years.

Several of the world’s most successful companies, including Sony, Texas Instruments, Intel and Tesla Motors, were founded by physicists, and there are many contemporary examples too. For example, Unitary, an AI company that identifies misinformation and deepfakes, was founded by Sasha Haco, who has a PhD in theoretical physics. In materials science, Aruna Zhuma is the co-founder of Global Graphene Group, which manufactures single layers of graphene oxide for use in electronics. Zhuma has nearly 500 patents, the second largest number of any inventor in the field.

In the last decade quantum technology, which encompasses computing, sensing and communications, has spawned hundreds of start-ups, often spun out from university research. This includes cybersecurity firm ID Quantique, super sensitive detectors from Single Quantum, and quantum computing from D-Wave. Overall, about 8–9% of students in the UK start businesses straight after they graduate, with just over half (58%) of these graduate entrepreneurs founding firms in their subject area.

However, even if you aren’t planning to set up your own business, entrepreneurship skills will be important no matter what you do with your degree. If you work in industry you will need to spot trends, understand customers’ needs and contribute to products and services. In universities, promotion often requires candidates to demonstrate “knowledge transfer”, which means working with partners outside academia.

Taking your ideas to the next level

The first step of kick-starting your entrepreneurship journey is to evaluate your existing experience and goals. Do you already have an idea that you want to take forward, or just want to develop skills that will broaden your career options?

If you’re exploring the possibilities of entrepreneurship you should look for curricular modules at your university. These are normally tailored to those with no previous experience and cover topics such as opportunity spotting, market research, basic finance, team building and intellectual property. In addition, in the UK at least, many postgraduate centres for doctoral training (CDTs) now offer modules in business and entrepreneurship as part of their training programmes. These courses sometimes give students the opportunity to take part in live company projects, which are a great way to gain skills.

You should also look out for extracurricular opportunities, from speaker events and workshops to more intensive bootcamps, competitions and start-up weekends. There is no mark or grade for these events, so they allow students to take risks and experiment.

Like any kind of research, commercializing physics requires resources such as equipment and laboratory space. For early-stage founders, access to business incubators – organizations that provide shared facilities – is invaluable. You would use an incubator at a relatively early stage to finalize your product, and they can be found in many universities.

Accelerator programmes, which aim to fast-track your idea once you have a product ready and usually run for a defined length of time, can also be beneficial. For example, the University of Southampton has the Future Worlds Programme based in the physical sciences faculty. Outside academia, the European Space Agency has incubators for space technology ideas at locations throughout Europe, and the Institute of Physics also has workspace and an accelerator programme for recently graduated physicists and especially welcomes quantum technology businesses. The Science and Technology Facilities Council (STFC) CERN Business Incubation Centre focuses on high-energy physics ideas and grants access to equipment that would be otherwise unaffordable for a new start-up.

More accelerator programmes supporting physics ideas include Duality, which is a Chicago-based 12-month accelerator programme for quantum ideas; Quantum Delta NL, based in the Netherlands, which provides programmes and shared facilities for quantum research; and Techstars Industries of the Future, which has locations worldwide.

Securing your future

It’s the multimillion-pound deals that make headlines but to get to that stage you will need to gain investors’ confidence, securing smaller funds to take your idea forward step-by-step. This could be used to protect your intellectual property with a patent, make a prototype or road test your technology.

Since early-stage businesses are high risk, this money is likely to come from grants and awards, with commercial investors such as venture capital or banks holding back until they see the idea can succeed. Funding can come from government agencies like the STFC in the UK, or US government scheme America’s Seed Fund. These grants are for encouraging innovation, applied research and for finding disruptive new technology, and no return is expected. Early-stage commercial funding might come from organizations such as Seedcamp, and some accelerator programmes offer funding, or at least organize a “demo day” on completion where you can showcase your venture to potential investors.

Group of students sat at a round table with large sheets of paper and Post-it notes

While you’re a student, you can take advantage of the venture competitions that run at many universities, where students pitch an idea to a panel of judges. The prizes can be significant, ranging from £10k to £100k, and often come with extra support such as lab space, mentoring and help filing patents. Some of these programmes are physics-specific, for example the Eli and Britt Harari Enterprise Award at the University of Manchester, which is sponsored by physics graduate Eli Harari (founder of SanDisc) awards funding for graphene-related ideas.

Finally, remember that physics innovations don’t always happen in the lab. Theoretical physicist Stephen Wolfram founded Wolfram Research in 1988, which makes computational technology including the answer engine Wolfram Alpha.

Making the grade

There are many examples of students and recent graduates making a success from entrepreneurship. Wai Lau is a Manchester physics graduate who also has a master’s of enterprise degree. He started a business focused on digital energy management, identifying energy waste, while learning about entrepreneurship. His business Cloud Enterprise has now branched out to a wider range of digital products and services.

Computational physics graduate Gregory Mead at Imperial College London started Musicmetric, which uses complex data analytics to keep track of and rank music artists and is used by music labels and artists. He was able to get funding from Imperial Innovations after making a prototype and Musicmetric was eventually bought by Apple.

AssestCool Thermal Metaphotonics technology cools overhead power lines reducing power losses using novel coatings. It entered the Venture Further competition at the University of Manchester and has now had a £2.25m investment from Gritstone Capital.

Entrepreneurship skills are being increasingly recognized as necessary for physics graduates. In the UK, the IOP Degree Accreditation Framework, the standard for physics degrees, expects students to have “business awareness, intellectual property, digital media and entrepreneurship skills”.

Thinking about taking the leap into business can be daunting, but university is the ideal time to think about entrepreneurship. You have nothing to lose and plenty of support available.

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