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New protocol makes an elusive superconducting signature measurable

Conversion of a hard-to-detect signal into a pattern that reveals d-wave pairing — **From immeasurable to measurable** Microwave pulses and lattice depth control manipulate fermions on a lattice (left), converting a hard-to-detect signal into a brickwork pattern (right) that reveals d-wave pairing, a key signature of high-temperature superconductors. (Courtesy: Adapted from D K Mark *et al. Phys. Rev. Lett.* **135** 123402 (2025))

Understanding the mechanism of high-temperature superconductivity could unlock powerful technologies, from efficient energy transmission to medical imaging, supercomputing and more. Researchers at Harvard University and the Massachusetts Institute of Technology have designed a new protocol to study a candidate model for high-temperature superconductivity (HTS), described in Physical Review Letters.

The model, known as the Fermi-Hubbard model, is believed to capture the essential physics of cuprate high-temperature superconductors, materials composed of copper and oxygen. The model describes fermions, such as electrons, moving on a lattice. The fermions experience two competing effects: tunnelling and on-site interaction. Imagine students in a classroom: they may expend energy to switch seats (tunnelling), avoid a crowded desk (repulsive on-site interaction) or share desks with friends (attractive on-site interaction). Such behaviour mirrors that of electrons moving between lattice sites.

Daniel Mark, first author of the study, notes that: “After nearly four decades of research, there are many detailed numerical studies and theoretical models on how superconductivity can emerge from the Fermi-Hubbard model, but there is no clear consensus [on exactly how it emerges].”

A precursor to understanding the underlying mechanism is testing whether the Fermi-Hubbard model gives rise to an important signature of cuprate HTS: d-wave pairing. This is a special type of electron pairing where the strength and sign of the pairing depend on the direction of electron motion. It contrasts with conventional low-temperature superconductors that exhibit s-wave pairing, in which the pairing strength is uniform in all directions.

Although physicists have developed robust methods for simulating the Fermi-Hubbard model with ultracold atoms, measuring d-wave pairing has been notoriously difficult. The new protocol aims to change that.

A change of perspective

A key ingredient in the protocol is the team’s use of “repulsive-to-attractive mapping”. The physics of HTS is often described by the repulsive Fermi-Hubbard model, in which electrons pay an energetic penalty for occupying the same lattice site, like disagreeing students sharing a desk. In this model, detecting d-wave pairing requires fermions to maintain a fragile quantum state as they move over large distances, which necessitates carefully fine-tuned experimental parameters.

To make the measurement more robust to experimental imperfection, the authors use a clever mathematical trick: they map from the repulsive model to the attractive one. In the attractive model, electrons receive an energetic benefit from being close together, like two friends in a classroom. The mapping is achieved by a particle–hole transformation, wherein spin-down electrons are reinterpreted as holes and vice versa. After mapping, the d-wave pairing signal becomes an observable that conserves local fermion number, thereby circumventing the challenge of long-range motion.

In its initial form, the d-wave pairing signal is difficult to measure. Drawing inspiration from digital quantum gates, the researchers divide their complex system into subsystems composed of pairs of lattice sites or dimers. Then, they apply a pulse sequence to make the observable measurable by simply counting fermions – a standard technique in the lab.

The pulse sequence begins with a global microwave pulse to manipulate the spin of the fermions, followed by a series of “hopping” and “idling” steps. The hopping step involves lowering the barrier between lattice sites, thereby increasing tunnelling. The idling step involves raising the barrier, allowing the system to evolve without tunnelling. Every step is carefully timed to reveal the d-wave pairing information at the end of the sequence.

Quantum microscopy sheds light on high-temperature superconductivity

The researchers report that their protocol is sample-efficient, experimentally viable, and generalizable to other observables that conserve local fermion number and act on dimers.

This work adds to a growing field that combines components of analogue quantum systems with digital gates to deeply study complex quantum phenomena. “All the experimental ingredients in our protocol have been demonstrated in existing experiments, and we are in discussion with several groups on possible use cases,” Mark tells Physics World.

Interface engineered ferromagnetism

Exchange-coupled interfaces offer a powerful route to stabilising and enhancing ferromagnetic properties in two-dimensional materials, such as transition metal chalcogenides. These materials exhibit strong correlations among charge, spin, orbital, and lattice degrees of freedom, making them an exciting area for emergent quantum phenomena.

Cr₂Te₃’s crystal structure naturally forms layers that behave like two-dimensional sheets of magnetic material. Each layer has magnetic ordering (ferromagnetism), but the layers are not tightly bonded in the third dimension and are considered “quasi-2D.” These layers are useful for interface engineering. Using a vacuum-based technique for atomically precise thin-film growth, known as molecular beam epitaxy, the researchers demonstrate wafer-scale synthesis of Cr₂Te₃ down to monolayer thickness on insulating substrates. Remarkably, robust ferromagnetism persists even at the monolayer limit, a critical milestone for 2D magnetism.

When Cr₂Te₃ is proximitized (an effect that occurs when one material is placed in close physical contact with another so that its properties are influenced by the neighbouring material) to a topological insulator, specifically (Bi,Sb)₂Te₃, the Curie temperature, the threshold between ferromagnetic and paramagnetic phases, increases from ~100 K to ~120 K. This enhancement is experimentally confirmed via polarized neutron reflectometry, which reveals a substantial boost in magnetization at the interface.

Theoretical modelling attributes this magnetic enhancement to the Bloembergen–Rowland interaction which is a long-range exchange mechanism mediated by virtual intraband transitions. Crucially, this interaction is facilitated by the topological insulator’s topologically protected surface states, which are spin-polarized and robust against disorder. These states enable long-distance magnetic coupling across the interface, suggesting a universal mechanism for Curie temperature enhancement in topological insulator-coupled magnetic heterostructures.

This work not only demonstrates a method for stabilizing 2D ferromagnetism but also opens the door to topological electronics, where magnetism and topology are co-engineered at the interface. Such systems could enable novel quantum hybrid devices, including spintronic components, topological transistors, and platforms for realizing exotic quasiparticles like Majorana fermions.

Read the full article

Enhanced ferromagnetism in monolayer Cr2Te3 via topological insulator coupling

Yunbo Ou et al 2025 Rep. Prog. Phys. 88 060501

Do you want to learn more about this topic?

Interacting topological insulators: a review by Stephan Rachel (2018)

Probing the fundamental nature of the Higgs Boson

First proposed in 1964, the Higgs boson plays a key role in explaining why many elementary particles of the Standard Model have a rest mass. Many decades later the Higgs boson was observed in 2012 by the ATLAS and CMS collaborations at the Large Hadron Collider (LHC), confirming the decades old prediction.

This discovery made headline news at the time and, since then, the two collaborations have been performing a series of measurements to establish the fundamental nature of the Higgs boson field and of the quantum vacuum. Researchers certainly haven’t stopped working on the Higgs though. In subsequent years, a series of measurements have been performed to establish the fundamental nature of the new particle.

One key measurement comes from studying a process known as off-shell Higgs boson production. This is the creation of Higgs bosons with a mass significantly higher than their typical on-shell mass of 125 GeV. This phenomenon occurs due to quantum mechanics, which allows particles to temporarily fluctuate in mass.

This kind of production is harder to detect but can reveal deeper insights into the Higgs boson’s properties, especially its total width, which relates to how long it exists before decaying. This in turn, allows us to test key predictions made by the Standard Model of particle physics.

Previous observations of this process had been severely limited in their sensitivity. In order to improve on this, the ATLAS collaboration had to introduce a completely new way of interpreting their data (read here for more details).

They were able to provide evidence for off-shell Higgs boson production with a significance of 2.5𝜎 (corresponding to a 99.38% likelihood), using events with four electrons or muons, compared to a significance of 0.8𝜎 using traditional methods in the same channel.

The results mark an important step forward in understanding the Higgs boson as well as other high-energy particle physics phenomena.

Read the full article

Measurement of off-shell Higgs boson production in the decay channel using a neural simulation-based inference technique in 13 TeV pp collisions with the ATLAS detector – IOPscience

The ATLAS Collaboration, 2025 Rep. Prog. Phys. 88 057803

Fabrication and device performance of Ni0/Ga₂O₃ heterojunction power rectifiers

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This talk shows how integrating p-type NiO to form NiO/Ga_₂O_₃ heterojunction rectifiers overcomes that barrier, enabling record-class breakdown and Ampere-class operation. It will cover device structure/process optimization, thermal stability to high temperatures, and radiation response – with direct ties to today’s priorities: EV fast charging, AI data‑center power systems, and aerospace/space‑qualified power electronics.

An interactive Q&A session follows the presentation.

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Jian-Sian Li

Jian-Sian Li received the PhD in chemical engineering from the University of Florida in 2024, where his research focused on NiO/β-Ga_₂O_₃ heterojunction power rectifiers, includes device design, process optimization, fast switching, high-temperature stability, and radiation tolerance (γ, neutron, proton). His work includes extensive electrical characterization and microscopy/TCAD analysis supporting device physics and reliability in harsh environments. Previously, he completed his BS and MS at National Taiwan University (2015, 2018), with research spanning phoretic/electrokinetic colloids, polymers for OFETs/PSCs, and solid-state polymer electrolytes for Li-ion batteries. He has since transitioned to industry at Micron Technology.

Randomly textured lithium niobate gives snapshot spectrometer a boost

A new integrated “snapshot spectroscopy” system developed in China can determine the spectral and spatial composition of light from an object with much better precision than other existing systems. The instrument uses randomly textured lithium niobate and its developers have used it for astronomical imaging and materials analysis – and they say that other applications are possible.

Spectroscopy is crucial to analysis of all kinds of objects in science and engineering, from studying the radiation emitted by stars to identifying potential food contaminants. Conventional spectrometers – such as those used on telescopes – rely on diffractive optics to separate incoming light into its constituent wavelengths. This makes them inherently large, expensive and inefficient at rapid image acquisition as the light from each point source has to be spatially separated to resolve the wavelength components.

In recent years researchers have combined computational methods with advanced optical sensors to create computational spectrometers with the potential to rival conventional instruments. One such approach is hyperspectral snapshot imaging, which captures both spectral and spatial information in the same image. There are currently two main snapshot-imaging techniques available. Narrowband-filtered snapshot spectral imagers comprise a mosaic pattern of narrowband filters and acquire an image by taking repeated snapshots at different wavelengths. However, these trade spectral resolution with spatial resolution, as each extra band requires its own tile within the mosaic. A more complex alternative design – the broadband-modulated snapshot spectral imager – uses a single, broadband detector covered with a spatially varying element such as a metasurface that interacts with the light and imprints spectral encoding information onto each pixel. However, these are complex to manufacture and their spectral resolution is limited to the nanometre scale.

Random thicknesses

In the new work, researchers led by Lu Fang at Tsinghua University in Beijing unveil a spectroscopy technique that utilizes the nonlinear optical properties of lithium niobate to achieve sub-Ångström spectral resolution in a simply fabricated, integrated snapshot detector they call RAFAEL. A lithium niobate layer with random, sub-wavelength thickness variations is surrounded by distributed Bragg reflectors, forming optical cavities. These are integrated into a stack with a set of electrodes. Each cavity corresponds to a single pixel. Incident light enters from one side of a cavity, interacting with the lithium niobate repeatedly before exiting and being detected. Because lithium niobate is nonlinear, its response varies with the wavelength of the light.

The researchers then applied a bias voltage using the electrodes. The nonlinear optical response of lithium niobate means that this bias alters its response to light differently at different wavelengths. Moreover, the random variation of the lithium niobate’s thickness around the surface means that the wavelength variation is spatially specific.

The researchers designed a machine learning algorithm and trained it to use this variation of applied bias voltage with resulting wavelength detected at each point to reconstruct the incident wavelengths on the detector at each point in space.

“The randomness is useful for making the equations independent,” explains Fang; “We want to have uncorrelated equations so we can solve them.”

Thousands of stars

The researchers showed that they could achieve 88 Hz snapshot spectroscopy on a grid of 2048×2048 pixels with a spectral resolution of 0.5 Å (0.05 nm) between wavelengths of 400–1000 nm. They demonstrated this by capturing the full atomic absorption spectra of up to 5600 stars in a single snapshot. This is a two to four orders of magnitude improvement in observational efficiency over world-class astronomical spectrometers. They also demonstrated other applications, including a materials analysis challenge involving the distinction of a real leaf from a fake one. The two looked identical at optical wavelengths, but, using its broader range of wavelengths, RAFAEL was able to distinguish between the two.

The researchers are now attempting to improve the device further: “I still think that sub-Ångstrom is not the ending – it’s just the starting point,” says Fu. “We want to push the limit of our resolution to the picometre.” In addition, she says, they are working on further integration of the device – which requires no specialized lithography – for easier use in the field. “We’ve already put this technology on a drone platform,” she reveals. The team is also working with astronomical observatories such as Gran Telescopio Canarias in La Palma, Spain.

The research is described in Nature.

Computational imaging expert David Brady of Duke University in North Carolina is impressed by the instrument. “It’s a compact package with extremely high spectral resolution,” he says; “Typically an optical instrument, like a CMOS sensor that’s used here, is going to have between 10,000 and 100,000 photo-electrons per pixel. That’s way too many photons for getting one measurement…I think you’ll see that with spectral imaging as is done here, but also with temporal imaging. People are saying you don’t need to go at 30 frames second, you can go at a million frames per second and push closer to the single photon limit, and then that would require you to do computation to figure out what it all means.”

Tumour-specific radiofrequency fields suppress brain cancer growth

A research team headed up at Wayne State University School of Medicine in the US has developed a novel treatment for glioblastoma, based on exposure to low levels of radiofrequency electromagnetic fields (RF EMF). The researchers demonstrated that the new therapy slows the growth of glioblastoma cells in vitro and, for the first time, showed its feasibility and clinical impact in patients with brain tumours.

The study, led by Hugo Jimenez and reported in Oncotarget, uses a device developed by TheraBionic that delivers amplitude-modulated 27.12 MHz RF EMF throughout the entire body, via a spoon-shaped antenna placed on the tongue. Using tumour-specific modulation frequencies, the device has already received US FDA approval for treating patients with advanced hepatocellular carcinoma (HCC, a liver cancer), while its safety and effectiveness are currently being assessed in clinical trials in patients with pancreatic, colorectal and breast cancer.

In this latest work, the team investigated its use in glioblastoma, an aggressive and difficult to treat brain tumour.

To identify the particular frequencies needed to treat glioblastoma, the team used a non-invasive biofeedback method developed previously to study patients with various types of cancer. The process involves measuring variations in skin electrical resistance, pulse amplitude and blood pressure while individuals are exposed to low levels of amplitude-modulated frequencies. The approach can identify the frequencies, usually between 1 Hz and 100 kHz, specific to a single tumour type.

Jimenez and colleagues first examined the impact of glioblastoma-specific amplitude-modulated RF EMF (GBMF) on glioblastoma cells, exposing various cell lines to GBMF for 3 h per day at the exposure level used for patient treatments. After one week, GBMF decreased the proliferation of three glioblastoma cell lines (U251, BTCOE-4765 and BTCOE-4795) by 34.19%, 15.03% and 14.52%, respectively.

The team note that the level of this inhibitive effect (15–34%) is similar to that observed in HCC cell lines (19–47%) and breast cancer cell lines (10–20%) treated with tumour-specific frequencies. A fourth glioblastoma cell line (BTCOE-4536) was not inhibited by GBMF, for reasons currently unknown.

Next, the researchers examined the effect of GBMF on cancer stem cells, which are responsible for treatment resistance and cancer recurrence. The treatment decreased the tumour sphere-forming ability of U251 and BTCOE-4795 cells by 36.16% and 30.16%, respectively – also a comparable range to that seen in HCC and breast cancer cells.

Notably, these effects were only induced by frequencies associated with glioblastoma. Exposing glioblastoma cells to HCC-specific modulation frequencies had no measurable impact and was indistinguishable from sham exposure.

Looking into the underlying treatment mechanisms, the researchers hypothesized that – as seen in breast cancer and HCC – glioblastoma cell proliferation is mediated by T-type voltage-gated calcium channels (VGCC). In the presence of a VGCC blocker, GBMF did not inhibit cell proliferation, confirming that GBMF inhibition of cell proliferation depends on T-type VGCCs, in particular, a calcium channel known as CACNA1H.

The team also found that GBMF blocks the growth of glioblastoma cells by modulating the “Mitotic Roles of Polo-Like Kinase” signalling pathway, leading to disruption of the cells’ mitotic spindles, critical structures in cell replication.

A clinical first

Finally, the researchers used the TheraBionic device to treat two patients: a 38-year-old patient with recurrent glioblastoma and a 47-year-old patient with the rare brain tumour oligodendroglioma. The first patient showed signs of clinical and radiological benefit following treatment; the second exhibited stable disease and tolerated the treatment well.

“This is the first report showing feasibility and clinical activity in patients with brain tumour,” the authors write. “Similarly to what has been observed in patients with breast cancer and hepatocellular carcinoma, this report shows feasibility of this treatment approach in patients with malignant glioma and provides evidence of anticancer activity in one of them.”

The researchers add that a previous dosimetric analysis of this technique measured a whole-body specific absorption rate (SAR, the rate of energy absorbed by the body when exposed to RF EMF) of 1.35 mW/kg and a peak spatial SAR (over 1 g of tissue) of 146–352 mW/kg. These values are well within the safety limits set by the ICNIRP (whole-body SAR of 80 mW/kg; peak spatial SAR of 2000 mW/kg). Organ-specific values for grey matter, white matter and the midbrain also had mean SAR ranges well within the safety limits.

The team concludes that the results justify future preclinical and clinical studies of the TheraBionic device in this patient population. “We are currently in the process of designing clinical studies in patients with brain tumors,” Jimenez tells Physics World.

Entangled light leads to quantum advantage

Photo showing the optical components used to manipulate the quantum fluctuations of light — Quantum manipulation: The squeezer – an optical parametric oscillator (OPO) that uses a nonlinear crystal inside an optical cavity to manipulate the quantum fluctuations of light – is responsible for the entanglement. (Courtesy: Jonas Schou Neergaard-Nielsen)

Physicists at the Technical University of Denmark have demonstrated what they describe as a “strong and unconditional” quantum advantage in a photonic platform for the first time. Using entangled light, they were able to reduce the number of measurements required to characterize their system by a factor of 10¹¹, with a correspondingly huge saving in time.

“We reduced the time it would take from 20 million years with a conventional scheme to 15 minutes using entanglement,” says Romain Brunel, who co-led the research together with colleagues Zheng-Hao Liu and Ulrik Lund Andersen.

Although the research, which is described in Science, is still at a preliminary stage, Brunel says it shows that major improvements are achievable with current photonic technologies. In his view, this makes it an important step towards practical quantum-based protocols for metrology and machine learning.

From individual to collective measurement

Quantum devices are hard to isolate from their environment and extremely sensitive to external perturbations. That makes it a challenge to learn about their behaviour.

To get around this problem, researchers have tried various “quantum learning” strategies that replace individual measurements with collective, algorithmic ones. These strategies have already been shown to reduce the number of measurements required to characterize certain quantum systems, such as superconducting electronic platforms containing tens of quantum bits (qubits), by as much as a factor of 10⁵.

A photonic platform

In the new study, Brunel, Liu, Andersen and colleagues obtained a quantum advantage in an alternative “continuous-variable” photonic platform. The researchers note that such platforms are far easier to scale up than superconducting qubits, which they say makes them a more natural architecture for quantum information processing. Indeed, photonic platforms have already been crucial to advances in boson sampling, quantum communication, computation and sensing.

The team’s experiment works with conventional, “imperfect” optical components and consists of a channel containing multiple light pulses that share the same pattern, or signature, of noise. The researchers began by performing a procedure known as quantum squeezing on two beams of light in their system. This caused the beams to become entangled – a quantum phenomenon that creates such a strong linkage that measuring the properties of one instantly affects the properties of the other.

The team then measured the properties of one of the beams (the “probe” beam) in an experiment known as a 100-mode bosonic displacement process. According to Brunel, one can imagine this experiment as being like tweaking the properties of 100 independent light modes, which are packets or beams of light. “A ‘bosonic displacement process’ means you slightly shift the amplitude and phase of each mode, like nudging each one’s brightness and timing,” he explains. “So, you then have 100 separate light modes, and each one is shifted in phase space according to a specific rule or pattern.”

By comparing the probe beam to the second (“reference”) beam in a single joint measurement, Brunel explains that he and his colleagues were able to cancel out much of the uncertainties in these measurements. This meant they could extract more information per trial than they could have by characterizing the probe beam alone. This information boost, in turn, allowed them to significantly reduce the number of measurements – in this case, by a factor of 10¹¹.

While the DTU researchers acknowledge that they have not yet studied a practical, real-world system, they emphasize that their platform is capable of “doing something that no classical system will ever be able to do”, which is the definition of a quantum advantage. “Our next step will therefore be to study a more practical system in which we can demonstrate a quantum advantage,” Brunel tells Physics World.

Queer Quest: a quantum-inspired journey of self-discovery

This episode of Physics World Stories features an interview with Jessica Esquivel and Emily Esquivel – the creative duo behind Queer Quest. The event created a shared space for 2SLGBTQIA+ Black and Brown people working in science, technology, engineering, arts and mathematics (STEAM).

Mental health professionals also joined Queer Quest, which was officially recognized by UNESCO as part of the International Year of Quantum Science and Technology (IYQ). Over two days in Chicago this October, the event brought science, identity and wellbeing into powerful conversation.

Jessica Esquivel, a particle physicist and associate scientist at Fermilab, is part of the Muon g-2 experiment, pushing the limits of the Standard Model. Emily Esquivel is a licensed clinical professional counsellor. Together, they run Oyanova, an organization empowering Black and Brown communities through science and wellness.

Quantum metaphors and resilience through connection

queer quest advert - a woman's face inside a planet — Courtesy: Oyanova

Queer Quest blended keynote talks, with collective conversations, alongside meditation and other wellbeing activities. Panellists drew on quantum metaphors – such as entanglement – to explore identity, community and mental health.

In a wide-ranging conversation with podcast host Andrew Glester, Jessica and Emily speak about the inspiration for the event, and the personal challenges they have faced within academia. They speak about the importance of building resilience through community connections, especially given the social tensions in the US right now.

Hear more from Jessica Esquivel in her 2021 Physics World Stories appearance on the latest developments in muon science.

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 year for more coverage of the IYQ.

Find out more on our quantum channel.

Fingerprint method can detect objects hidden in complex scattering media

Buried metal spheres can be seen using new fingerprint imaging method — **Imaging buried objects** Left: artistic impression of metal spheres buried in small glass beads; centre: conventional ultrasound image; right: the new technology can precisely determine the positions of the metal spheres. (Courtesy: TU Wien/Arthur Le Ber)

Physicists have developed a novel imaging technique for detecting and characterizing objects hidden within opaque, highly scattering material. The researchers, from France and Austria, showed that their new mathematical approach, which utilizes the fact that hidden objects generate their own complex scattering pattern, or “fingerprint”, can work on biological tissue.

Viewing the inside of the human body is challenging due to the scattering nature of tissue. With ultrasound, when waves propagate through tissue they are reflected, bounce around and scatter chaotically, creating noise that obscures the signal from the object that the medical practitioner is trying to see. The further you delve into the body the more incoherent the image becomes.

There are techniques for overcoming these issues, but as scattering increases – in more complex media or as you push deeper through tissue – they struggle and unpicking the required signal becomes too complex.

The scientists behind the latest research, from the Institut Langevin in Paris, France and TU Wien in Vienna, Austria, say that rather than compensating for scattering, their technique instead relies on detecting signals from the hidden object in the disorder.

Objects buried in a material create their own complex scattering pattern, and the researchers found that if you know an object’s specific acoustic signal it’s possible to find it in the noise created by the surrounding environment.

“We cannot see the object, but the backscattered ultrasonic wave that hits the microphones of the measuring device still carries information about the fact that it has come into contact with the object we are looking for,” explains Stefan Rotter, a theoretical physicist at TU Wien.

Rotter and his colleagues examined how a series of objects scattered ultrasound waves in an interference-free environment. This created what they refer to as fingerprint matrices: measurements of the specific, characteristic way in which each object scattered the waves.

The team then developed a mathematical method that allowed them to calculate the position of each object when hidden in a scattering medium, based on its fingerprint matrix.

“From the correlations between the measured reflected wave and the unaltered fingerprint matrix, it is possible to deduce where the object is most likely to be located, even if the object is buried,” explains Rotter.

The team tested the technique in three different scenarios. The first experiment trialled the ultrasound imaging of metal spheres in a dense suspension of glass beads in water. Conventional ultrasound failed in this setup and the spheres were completely invisible, but with their novel fingerprint method the researchers were able to accurately detect them.

Next, to examine a medical application for the technique, the researchers embedded lesion markers often used to monitor breast tumours in a foam designed to mimic the ultrasound scattering of soft tissue. These markers can be challenging to detect due to scatterers randomly distributed in human tissue. With the fingerprint matrix, however, the researchers say that the markers were easy to locate.

Finally, the team successfully mapped muscle fibres in a human calf using the technique. They claim this could be useful for diagnosing and monitoring neuromuscular diseases.

According to Rotter and his colleagues, their fingerprint matrix method is a versatile and universal technique that could be applied beyond ultrasound to all fields of wave physics. They highlight radar and sonar as examples of sensing techniques where target identification and detection in noisy environments are long-standing challenges.

“The concept of the fingerprint matrix is very generally applicable – not only for ultrasound, but also for detection with light,” Rotter says. “It opens up important new possibilities in all areas of science where a reflection matrix can be measured.”

The researchers report their findings in Nature Physics.

Ask me anything: Kirsty McGhee – ‘Follow what you love: you might end up doing something you never thought was an option’

What skills do you use every day in your job?

Obviously, I write: I wouldn’t be a very good science writer if I couldn’t. So communication skills are vital. Recently, for example, Qruise launched a new magnetic-resonance product for which I had to write a press release, create a new webpage and do social-media posts. That meant co-ordinating with lots of different people, finding out the key features to advertise, identifying the claims we wanted to make – and if we have the data to back those claims up. I’m not an expert in quantum computing or magnetic-resonance imagining or even marketing so I have to pick things up fast and then translate technically complex ideas from physics and software into simple messages for a broader audience. Thankfully, my colleagues are always happy to help. Science writing is a difficult task but I think I’m getting better at it.

What do you like best and least about your job?

I love the variety and the fact that I’m doing so many different things all the time. If there’s a day I feel I want something a little bit lighter, I can do some social media or the website, which is more creative. On the other hand, if I feel I could really focus in detail on something then I can write some documentation that is a little bit more technical. I also love the flexibility of remote working, but I do miss going to the office and socialising with my colleagues on a regular basis. You can’t get to know someone as well online, it’s nicer to have time with them in person.

What do you know today, that you wish you knew when you were starting out in your career?

That’s a hard one. It would be easy to say I wish I’d known earlier that I could combine science and writing and make a career out of that. On the other hand, if I’d known that, I might not have done my PhD – and if I’d gone into writing straight after my undergraduate degree, I perhaps wouldn’t be where I am now. My point is, it’s okay not to have a clear plan in life. As children, we’re always asked what we want to be – in my case, my dream from about the age of four was to be a vet. But then I did some work experience in a veterinary practice and I realized I’m really squeamish. It was only when I was 15 or 16 that I discovered I wanted to do physics because I liked it and was good at it. So just follow the things you love. You might end up doing something you never even thought was an option.

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