Now, a team of researchers has investigated how the narrow temperature ranges of a tropical climate impact the incidence of a specific type of myocardial infarction (the medical term for a heart attack) in Singapore. The researchers say their findings, published in the journal Science of the Total Environment, could have health policy implications for populations within cosmopolitan cities in the tropics.

“Using 10 years of nationally collected data, we found strong evidence that a drop of 1°C in ambient temperature increased the risk of a type of acute myocardial infarction in the population by 12 per cent,” said co-senior author Professor Marcus Ong, Director of the Health Services & Systems Research Programme and the Pre-hospital & Emergency Research Centre (PERC) at Duke-NUS Medical School.

“Furthermore, people aged 65 and above appeared to be about 20 per cent more vulnerable to cooler temperatures compared to younger people,” added Prof Ong, who is also Senior Consultant at the Department of Emergency Medicine at Singapore General Hospital (SGH).

The study, which was conducted in collaboration with Singapore’s National Environment Agency (NEA), analysed daily patient records from the Singapore Myocardial Infarction Registry. The researchers were specifically looking for people who experienced non-ST-segment elevation myocardial infarction (NSTEMI). This is a type of acute heart attack that happens when a blood vessel feeding the heart becomes partially blocked. When doctors examine the patient’s electrocardiogram (ECG) results, they don’t find the easily identifiable ST elevation that signifies another type of heart attack, STEMI, which occurs when the coronary artery is completely blocked. Since the 1980s, the incidence of NSTEMI has risen while that of STEMI has declined.

The researchers were able to collect 60,643 reports of NSTEMI between 2009 and 2018. They then statistically analysed how the onset of NSTEMI in these patients correlated with local meteorological data obtained from weather stations across Singapore, including mean temperature and rainfall.

Cooler ambient temperatures were independently associated with an increased risk of NSTEMI up to 10 days after a temperature drop. There were no gender differences relating to the effects of warmer or cooler temperatures on NSTEMI risk. Nor were changes in rainfall associated with an increased risk.

“Our study found that even in a relatively warm part of the world, cooler ambient temperatures increased the risk of heart attacks,” said Dr Andrew Ho, one of the study’s first authors, who is an Assistant Professor with PERC and an Associate Consultant with SGH’s Department of Emergency Medicine. “This improves our understanding that deviations from the temperature that one is used to can lead to harmful bodily stress. Consistent with our previous studies that showed that the elderly were more susceptible to environmental stressors including air pollution, we found some evidence that this group of individuals were at greater risk of heart attacks at cooler temperatures.”

“There are several individual-level risk factors for cardiovascular disease, but none are as widely experienced as weather patterns,” said Dr Joel Aik, an environmental epidemiologist and co-senior author of the study from NEA, who is also an Adjunct Assistant Professor with PERC. “Daily weather variations have the capacity to trigger cardiovascular disease events in at-risk individuals, with particular implications for Singapore’s ageing population. In the context of climate change, these findings highlight a risk factor of substantial public health concern.”

Further research over a longer period is needed to confirm the results. The team also recommends research that helps to identify the biological pathways involved in increased vulnerability of the elderly to cold-related NSTEMI in the tropics.

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Lead author Theresa Andrasfay, a postdoctoral scholar at the University of Southern California Leonard Davis School of Gerontology, and coauthor Noreen Goldman at the Princeton School of Public and International Affairs first examined the pandemic’s effect on U.S. life expectancy in October 2020. Their initial study, published in Proceedings of the National Academy of Sciences in January 2021, showed that 2020 presented the largest single-year decline in life expectancy in at least 40 years and the lowest life expectancy estimated since 2003.

The updated analysis, published in PLOS ONE, indicates that U.S. life expectancy at birth decreased by 2.2 years from 78.8 in 2019 to 76.6 in 2021. The estimated decrease in life expectancy for 2021 is 0.6 years larger than the decrease observed in 2020, Andrasfay said.

“Despite the availability of effective vaccines, life expectancy continued to decline in 2021. Part of this is due to the large number of COVID-19 deaths that occurred in the beginning of 2021, before many individuals were eligible for vaccination,” she said. “But even once all adults became eligible for vaccination, many chose not to be vaccinated and even vaccinated individuals were not completely protected against the highly transmissible Delta and Omicron variants.”

The study highlighted that significant racial disparities in loss of lifespan have endured throughout the pandemic. Between 2019 and 2021, non-Latino whites lost 2 years on average, while non-Latino Blacks lost 3.5 years and Latinos lost 3.7 years of life expectancy. As noted in Andrasfay and Goldman’s previous analyses, Black and Latino Americans have experienced a disproportionate burden of coronavirus infections and deaths, reflecting persistent structural inequalities that heighten risk of exposure to and death from COVID-19. Goldman noted that “although Whites experienced a larger drop in life expectancy between 2020 and 2021 than the Black and Latino populations, resulting in a very modest reduction in racial and ethnic differences, the disparities in life expectancy loss since the start of the pandemic remain regrettably and unacceptably large.”

Although COVID-19 is the primary cause of continued life expectancy reductions in 2021, “increases in other causes of death relative to pre-pandemic levels contribute to these life expectancy declines,” the authors wrote. The pandemic appears to have played a role in the increase of drug overdose deaths in 2020 and 2021, and increased mortality from conditions such as heart disease or diabetes may be attributable to complications of Covid-19 infections and/or health care shortages and delays.

This week the CDC also released provisional estimates of life expectancy in 2021. “We did not have access to the same level of detailed data as the CDC, so we arrived at slightly different life expectancy estimates,” Andrasfay said. “Despite these differences, our results are largely in agreement in that we find continued life expectancy reductions in 2021 and persistent racial and ethnic disparities.”

“COVID-19 mortality has been lower in the first half of 2022 compared to 2021, so if there is a successful booster campaign in the fall and the dominant strains have lower fatality rates than previous variants, it is possible that 2022 life expectancy may improve relative to 2021, though it is unlikely to return to levels seen prior to 2020,” she added. “However, what happens with 2022 life expectancy will ultimately depend on this coming fall and winter.”

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Materials provided by University of Southern California. Original written by Beth Newcomb. Note: Content may be edited for style and length.

The conditions in the interior of icy giant planets like Neptune and Uranus are extreme: temperatures reach several thousand degrees Celsius, and the pressure is millions of times greater than in the Earth’s atmosphere. Nonetheless, states like this can be simulated briefly in the lab: powerful laser flashes hit a film-like material sample, heat it up to 6,000 degrees Celsius for the blink of an eye and generate a shock wave that compresses the material for a few nanoseconds to a million times the atmospheric pressure. “Up to now, we used hydrocarbon films for these kinds of experiment,” explains Dominik Kraus, physicist at HZDR and professor at the University of Rostock. “And we discovered that this extreme pressure produced tiny diamonds, known as nanodiamonds.”

Using these films, however, it was only partially possible to simulate the interior of planets — because ice giants not only contain carbon and hydrogen but also vast amounts of oxygen. When searching for suitable film material, the group hit on an everyday substance: PET, the resin out of which ordinary plastic bottles are made. “PET has a good balance between carbon, hydrogen and oxygen to simulate the activity in ice planets,” Kraus explains. The team conducted its experiments at SLAC National Accelerator Laboratory in California, the location of the Linac Coherent Light Source (LCLS), a powerful, accelerator-based X-ray laser. They used it to analyze what happens when intensive laser flashes hit a PET film, employing two measurement methods at the same time: X-ray diffraction to determine whether nanodiamonds were produced and so-called small-angle scattering to see how quickly and how large the diamonds grew.

A big helper: oxygen

“The effect of the oxygen was to accelerate the splitting of the carbon and hydrogen and thus encourage the formation of nanodiamonds,” says Dominik Kraus, reporting on the results. “It meant the carbon atoms could combine more easily and form diamonds.” This further supports the assumption that it literally rains diamonds inside the ice giants. The findings are probably not just relevant to Uranus and Neptune but to innumerable other planets in our galaxy as well. While such ice giants used to be thought of as rarities, it now seems clear that they are probably the most common form of planet outside the solar system.

The team also encountered hints of another kind: In combination with the diamonds, water should be produced — but in an unusual variant. “So-called superionic water may have formed,” Kraus opines. “The oxygen atoms form a crystal lattice in which the hydrogen nuclei move around freely.” Because the nuclei are electrically charged, superionic water can conduct electric current and thus help to create the ice giants’ magnetic field. In their experiments, however, the research group was not yet able to unequivocally prove the existence of superionic water in the mixture with diamonds. This is planned to happen in close collaboration with the University of Rostock at the European XFEL in Hamburg, the world’s most powerful X-ray laser. There, HZDR heads the international user consortium HIBEF which offers ideal conditions for experiments of this kind.

Precision plant for nanodiamonds

In addition to this rather fundamental knowledge, the new experiment also opens up perspectives for a technical application: the tailored production of nanometer-sized diamonds, which are already included in abrasives and polishing agents. In the future, they are supposed to be used as highly-sensitive quantum sensors, medical contrast agents and efficient reaction accelerators, for splitting CO2 for example. “So far, diamonds of this kind have mainly been produced by detonating explosives,” Kraus explains. “With the help of laser flashes, they could be manufactured much more cleanly in the future.”

The scientists’ vision: A high-performance laser fires ten flashes per second at a PET film which is illuminated by the beam at intervals of a tenth of a second. The nanodiamonds thus created shoot out of the film and land in a collecting tank filled with water. There they are decelerated and can then be filtered and effectively harvested. The essential advantage of this method in contrast to production by explosives is that “the nanodiamonds could be custom cut with regard to size or even doping with other atoms,” Dominik Kraus emphasizes. “The X-ray laser means we have a lab tool that can precisely control the diamonds’ growth.”

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Soil moisture is an important variable in forested and agricultural ecosystems alike, particularly under the recent drought conditions of past Maine summers. Despite the robust soil moisture monitoring networks and large, freely available databases, the cost of commercial soil moisture sensors and the power that they use to run can be prohibitive for researchers, foresters, farmers and others tracking the health of the land.

Along with researchers at the University of New Hampshire and University of Vermont, UMaine’s WiSe-Net designed a wireless sensor network that uses artificial intelligence to learn how to be more power efficient in monitoring soil moisture and processing the data. The research was funded by a grant from the National Science Foundation.

“AI can learn from the environment, predict the wireless link quality and incoming solar energy to efficiently use limited energy and make a robust low cost network run longer and more reliably,” says Ali Abedi, principal investigator of the recent study and professor of electrical and computer engineering at the University of Maine.

The software learns over time how to make the best use of available network resources, which helps produce power efficient systems at a lower cost for large scale monitoring compared to the existing industry standards.

WiSe-Net also collaborated with Aaron Weiskittel, director of the Center for Research on Sustainable Forests, to ensure that all hardware and software research is informed by the science and tailored to the research needs.

“Soil moisture is a primary driver of tree growth, but it changes rapidly, both daily as well as seasonally,” Weiskittel says. “We have lacked the ability to monitor effectively at scale. Historically, we used expensive sensors that collected at fixed intervals — every minute, for example — but were not very reliable. A cheaper and more robust sensor with wireless capabilities like this really opens the door for future applications for researchers and practitioners alike.”

The study was published Aug. 9, 2022, in the Springer’s International Journal of Wireless Information Networks.

Although the system designed by the researchers focuses on soil moisture, the same methodology could be extended to other types of sensors, like ambient temperature, snow depth and more, as well as scaling up the networks with more sensor nodes.

“Real-time monitoring of different variables requires different sampling rates and power levels. An AI agent can learn these and adjust the data collection and transmission frequency accordingly rather than sampling and sending every single data point, which is not as efficient,” Abedi says.

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The new findings, published in July in Chemical Science, may enable the rational design of unique materials based on the rippled sheet architecture.

“Our study establishes the rippled beta sheet layer configuration as a motif with general features and opens the road to structure-based design of unique molecular architectures, with potential for materials development and biomedical applications,” said Jevgenij Raskatov, associate professor of chemistry and biochemistry at UC Santa Cruz and corresponding author of the paper.

Proteins come in an enormous range of shapes and sizes to carry out their myriad structural and functional roles in living cells. Certain common structural motifs, such as the alpha helix, are found in many protein structures.

The rippled sheet is a variation on the pleated beta sheet, a well-known structural motif found in thousands of proteins. Linus Pauling and Robert Corey described the rippled beta sheet in 1953, two years after introducing the concept of the pleated beta sheet. While the pleated beta sheet is well known and often called simply the beta sheet, the rippled sheet remained a largely theoretical structure for decades.

In a previous study published in 2021, Raskatov’s team reported obtaining a rippled beta sheet structure by mixing a small peptide with equal amounts of its mirror image. The researchers used mirror-image forms of triphenylalanine, a short peptide consisting of three phenylalanine amino acids. The mirror-image peptides joined in pairs to form “dimers” with the predicted structure, but they did not form the extended, periodic rippled beta-sheet layer topography hypothesized by Pauling and Corey.

“The dimers packed together into herringbone layer structures, which raised doubt as to whether the periodic rippled beta-sheet layer configuration was viable,” Raskatov said.

In the new study, the researchers substituted other amino acids for one of the triphenylalanines to create slightly different tripeptides and their mirror-images. Using these new tripeptides, they were able to create three different aggregating peptide systems that formed extended antiparallel rippled beta sheet layers, in which mirror-image peptide strands were arranged in alternating fashion. The results of x-ray crystallography showed that the crystal structures are in excellent overall agreement with the predictions made by Pauling and Corey.

The co-first authors of the paper are Amaruka Hazari, a staff scientist in Raskatov’s lab, and Michael Sawaya at UCLA. Other coauthors include Timothy Johnstone at UC Santa Cruz and Niko Vlahakis, David Boyer, Jose Rodriguez, and David Eisenberg at UCLA. This work was supported by the National Institutes of Health.

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Materials provided by University of California – Santa Cruz. Original written by Tim Stephens. Note: Content may be edited for style and length.

While the SARS-CoV-2 virus was invisibly infecting people in 2020 through the air in hospitals, churches, workplaces and restaurants, people across the world were focused on disinfecting surfaces and washing their hands. Many governments and businesses installed plexiglass barriers that actually increased coronavirus spread, said Jose-Luis Jimenez, lead author of a new comprehensive historical assessment of major medical mistakes involving disease transmission, now published in the journal Indoor Air.

“History set us up for a poor response to the pandemic,” said Jimenez, fellow at the Cooperative Institute for Research in Environmental Sciences (CIRES) and distinguished professor of chemistry at CU Boulder. “We might have had millions of fewer deaths, hundreds of millions fewer cases, if we’d taken appropriate, effective action from the start.”

The overview, written with colleagues from 10 countries, illuminates the often deadly impact of “belief perseverance,” in which it can take years or decades to challenge a set of beliefs — especially when the consequence of changing a set of beliefs is costly. It’s less expensive to ask people to wash hands or disinfect surfaces than it is to update a ventilation system, for example, or to re-engineer school classrooms, city buses and corporate boardrooms.

The authors, who include physicians, virologists, public health specialists, aerosol scientists, engineers, historians, a sociologist and an architect, spin through numerous examples of fatal mistakes in the history of research on infectious diseases. In 1847, for example, a scientist working in Austria showed that handwashing by medical doctors reduced deadly puerperal fever in a clinic. His work was dismissed because at the time, established medical and scientific beliefs blamed “a miasma in the air.” Handwashing made no sense to the establishment, and the suggestion that physicians, themselves, might be spreading disease, offended many.

Half a century later, another prominent researcher, Charles Chapin, ridiculed the idea of spooky miasmas or infected air. Chapin’s own work on infection had suggested to him that “contact infection” was the predominant way most infections spread. But he also knew how difficult it was to persuade people to wash their hands and disinfect surfaces if they thought some diseases might spread through the air, and how difficult it would be to figure out how to clean the air itself. So he argued his “contact infection” theory without evidence and managed to effectively label airborne disease transmission as superstition.

Jimenez and his co-authors trace disease transmission history from Chapin to 2020, when the World Health Organization (WHO), Centers for Disease Control and Prevention (CDC) and other institutions expressed deep skepticism or outright denial that SARS-CoV-2 might spread through the air, despite increasing evidence it was doing just that.

Jimenez said he thinks that most people at WHO and CDC were honest in their skepticism in early 2020, just struggling to get their minds around the fact that the conventional way of thinking about respiratory infection transmission — spreading through heavy droplets falling on surfaces — might be inadequate to explain the pandemic.

“They were stuck on the theory, distorting the interpretation of the observations to match their pre-existing beliefs,” said Jimenez.

Others have suggested that economics have also been at play, much as with climate change.

It’s convenient to ask individuals to take small, individual actions like handwashing and driving less, Jimenez noted. It’s more expensive for institutions to make structural changes, such as increasing ventilation everywhere, or replacing fossil fuel infrastructure with renewable energy.

So in preparation for facing the next pandemic intelligently, Jimenez and his colleagues are first working to find allies, especially in the hardworking medical and public health professions where many people have been too busy saving lives to enter the discussion about disease transmission, but have direct experience.

“And confrontation is also needed when major institutions refuse to accept the science and to communicate it clearly,” Jimenez added. “Maybe we have to badger the establishment a little, like Florence Nightingale did.”

Nightingale “lobbied” the British government for decades to support her reforms at hospitals, increasing hygiene, ventilation and distance between beds at a time when it was still seen as unnecessary.

“Previous research has shown that misgendering, or incorrectly labeling someone’s gender identity, often harms a person’s mental and physical health,” said Samantha L. Tornello, assistant professor of human development and family studies at Penn State and principal investigator of the Gender Diverse Parents Study, who noted that gender identity is a person’s internal sense of their own gender — for example, woman, man, nonbinary, or another gender identity. “This new research suggests that transgender parents may offer their children supportive environments to explore their own gender identity and expression.”

Tornello and lead co-author Rachel G. Riskind, the Christina B. Gidynski Associate Professor of Psychology at Guilford College, also found a strong link between child age and the likelihood of labeling — the older the child, the more likely parents were to label their child’s gender identity. Transgender parents of elementary-school-aged children may be more likely than transgender parents of toddlers to label their child’s gender identity.

“This study can’t speak to whether transgender parents assign their children gendered names or pronouns, or otherwise socialize them in gendered ways,” Riskind said. “But it does suggest that transgender parents hesitate to label their child’s gender identity before their child can communicate it themselves.”

The study utilized web-based surveys of 64 nonbinary and binary transgender parents from across the United States. Binary transgender people are those who identify primarily as women, girls, men, or boys; nonbinary people are those whose gender identity is not captured by these labels.

The study measured children’s gender expression: their interest in masculinized and feminized toys (e.g., toolsets and jewelry), activities (e.g., climbing and playing house), and personality characteristics (e.g., enjoying tumble play and liking pretty things). Participants rated how often their child engaged with and enjoyed each item or activity.

The surveys also asked parents about the sex their child was assigned at birth and about their child’s current gender identity.

The team found that 41% of the participants did not report their child’s current gender identity, choosing either “unknown,” “choose not to label,” or “self-describe,” with a text field to write in their response. For “self-describe,” parents often described a gender-fluid child or a child who had not verbalized their gender identity. Several parents wrote, “I think it’s too early to know.” Although the surveys revealed that, on average, children’s play was conventionally gendered, there was a great deal of diversity within the sample. Older children of nonbinary parents, for example, may be more likely to engage in gender-expansive play.

The study published on Aug. 17 in the journal Frontiers in Psychology.

According to Tornello, “Some believe that parent gender identity has either everything, or nothing, to do with child gender expression. But this study suggests that the truth is somewhere in between.”

“This is one of the largest studies to focus on the gender of young children with transgender parents. It will further inform our understanding of gender development, parenting, and child development more broadly.”

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Materials provided by Penn State. Original written by Mary Campbell. Note: Content may be edited for style and length.

The ability to regenerate varies widely in animals. Most mammals and vertebrates have only limited regeneration capacity, while basal and simple animals that emerged early in evolution, like cnidarians and planarians, can regenerate their whole body. In all cases, the process of regeneration begins with wound healing. The cells at the site of injury proliferate and form an undifferentiated mass — a blastema — from which the missing structures are re-patterned. This activates genetic processes that also control embryonic development. To determine the molecular mechanisms involved, the research team led by Prof. Dr Thomas W. Holstein studied the freshwater polyp Hydra to understand the basic features of this activation of regeneration.

The core of their investigations is the doctoral thesis of Anja Tursch. She repeated the key experiment of Geneva naturalist Abraham Trembley (1710 to 1784) which led him to discover the regeneration phenomenon. The Hydra polyp is bisected, prompting the upper half to regenerate a new “head” and the lower half a new “foot” — hence totally different body parts can grow from the exact same tissue at the cut surface in the middle. Building on their previous work on Hydra regeneration, the researchers at the Centre for Organismal Studies (COS) of Heidelberg University have now shown how this is possible.

Regardless of where it occurs, any damage triggers nonspecific signals for an injury response, i.e. wound healing, via calcium ions and the production of reactive oxygen species. The signals are transmitted intracellularly by three mitogen-activated protein kinases — p38, JNKs, and ERK. Activation of these three molecules is required for both head and foot regeneration. Wnt signalling pathways are then activated that are important during embryonic development for the formation of rudimentary organs and the body axis. The generic signals of wound healing are thus transferred into position-specific signals of patterning and cell differentiation for regeneration.

“Our experiments show that the Wnt signalling pathway is a main component of the initially general injury response and, depending on signal strength, directs the tissue toward head or foot development,” explains Prof. Holstein. This is why, in the case of MAPK inhibition, the otherwise absent regeneration can be induced by artificially generated, recombinant Wnt proteins. “It was also surprising that in middle body parts that had both head and foot removed, heads can be induced at both ends in this way,” adds Dr Suat Özbek, a member of Prof. Holstein’s “Molecular Evolution and Genomics” research group at the COS.

Wnt/β-catenin, one piece of the Wnt signalling pathway, was already known to encode positional information for new head structure formation. In collaboration with mathematicians led by Prof. Dr Anna Marciniak-Czochra, the research team of Prof. Holstein and Dr Özbek developed a model that shows how basal positional information in the tissue transforms the initially undifferentiated injury response into a differential patterning process via the Wnt signalling pathway. “Because MAPKs and Wnts are highly evolutionarily conserved, this mechanism is likely deeply embedded in our genome, which is important for regenerative processes in vertebrates and mammals as well,” stresses Thomas Holstein.

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In physics, Schroedinger’s cat is an allegory for two of the most awe-inspiring effects of quantum mechanics: entanglement and superposition. Researchers from Dresden and Munich have now observed these behaviors on a much larger scale than that of the smallest of particles. Until now, materials that display properties like, e.g., magnetism have been known to have so-called domains — islands in which the materials properties are homogeneously either of one or a different kind (imagine them being either black or white, for example). Looking at lithium holmium fluoride (LiHoF₄), the physicists have now discovered a completely new phase transition, at which the domains surprisingly exhibit quantum mechanical features, resulting in their properties becoming entangled (being black and white at the same time). “Our quantum cat now has a new fur because we’ve discovered a new quantum phase transition in LiHoF₄ which has not previously been known to exist,” comments Matthias Vojta, Chair of Theoretical Solid State Physics at TUD.

Phase transitions and entanglement

We can easily observe the spontaneously changing properties of a substance if we look at water: at 100 degrees Celsius it evaporates into a gas, at zero degrees Celsius it freezes into ice. In both cases, these new states of matter form as a consequence of a phase transition where the water molecules rearrange themselves, thus changing the characteristics of the matter. Properties like magnetism or superconductivity emerge as a result of electrons undergoing phase transitions in crystals. For phase transitions at temperatures approaching the absolute zero at -273.15 degrees Celsius, quantum mechanical effects such as entanglement come into play, and one speaks of quantum phase transitions. “Even though there are more than 30 years of extensive research dedicated to phase transitions in quantum materials, we had previously assumed that the phenomenon of entanglement played a role only on a microscopic scale, where it involves only a few atoms at a time,” explains Christian Pfleiderer, Professor of Topology of Correlated Systems at the TUM.

Quantum entanglement is one of the most astonishing phenomena of physics, where the entangled quantum particles exist in a shared superposition state that allows for usually mutually exclusive properties (e.g., black and white) to occur simultaneously. As a rule, the laws of quantum mechanics only apply to microscopic particles. The research teams from Munich and Dresden have now succeeded in observing effects of quantum entanglement on a much larger scale, that of thousands of atoms. For this, they have chosen to work with the well-known compound LiHoF₄.

Spherical samples enable precision measurements

At very low temperatures, LiHoF₄ acts as a ferromagnet where all magnetic moments spontaneously point in the same direction. If you then apply a magnetic field exactly vertically to the preferred magnetic direction, the magnetic moments will change direction, which is known as fluctuations. The higher the magnetic field strength, the stronger these fluctuations become, until, eventually, the ferromagnetism disappears completely at a quantum phase transition. This leads to the entanglement of neighboring magnetic moments. “If you hold up a LiHoF₄ sample to a very strong magnet, it suddenly ceases to be spontaneously magnetic. This has been known for 25 years,” summarizes Vojta.

What is new is what happens when you change the direction of the magnetic field. “We discovered that the quantum phase transition continues to occur, whereas it had previously been believed that even the smallest tilt of the magnetic field would immediately suppress it,” explains Pfleiderer. Under these conditions, however, it is not individual magnetic moments but rather extensive magnetic areas, so-called ferromagnetic domains, that undergo these quantum phase transitions. The domains constitute entire islands of magnetic moments pointing in the same direction. “We have used spherical samples for our precision measurements. That is what enabled us to precisely study the behavior upon small changes in the direction of the magnetic field,” adds Andreas Wendl, who conducted the experiments as part of his doctoral dissertation.

From fundamental physics to applications

“We have discovered an entirely new type of quantum phase transitions where entanglement takes place on the scale of many thousands of atoms instead of just in the microcosm of only a few,” explains Vojta. “If you imagine the magnetic domains as a black-and-white pattern, the new phase transition leads to either the white or the black areas becoming infinitesimally small, i.e., creating a quantum pattern, bevor dissolving completely.” A newly developed theoretical model successfully explains the data obtained from the experiments. “For our analysis, we generalized existing microscopic models and also took into account the feedback of the large ferromagnetic domains to the microscopic properties,” elaborates Heike Eisenlohr, who performed the calculations as part of her PhD thesis.

The discovery of the new quantum phase transitions is important as a foundation and general frame of reference for the research of quantum phenomena in materials, as well as for new applications. “Quantum entanglement is applied and used in technologies like quantum sensors and quantum computers, amongst other things,” says Vojta. Pfleiderer adds: “Our work is in the area of fundamental research, which, however, can have a direct impact on the development of practical applications, if you use the materials properties in a controlled way.”

The research has been financially supported by the Excellence Strategy of the German Federal and State Governments within the Würzburg-Dresden Cluster of Excellence Complexity and Topology in Quantum Matter (ct.qmat) and the Cluster of Excellence Munich Center for Quantum Science and Technology (MCQST). In addition, the work has been supported by the European Research Council (ERC) via the Advanced Grant ExQuiSid and by the Deutsche Forschungsgemeinschaft (DFG) within the Collaborative Research Centers (SFB) 1143 und TRR80.