Science Corporation, founded by Neuralink’s first president, Max Hodak, has unveiled a prototype machine to extend the life of organs for longer periods.
Atoms in a one-dimensional quantum gas behave like a Newton’s cradle toy, transferring energy from atom to atom without dissipation. Developed by researchers at the TU Wien, Austria, this quantum fluid of ultracold, confined rubidium atoms can be used to simulate more complex solid-state systems. By measuring transport quantities within this “perfect” atomic system, the team hope to obtain a deeper understanding of how transport phenomena and thermodynamics behave at the quantum level.
Physical systems transport energy, charge and mass in various ways. Electrical currents streaming along a wire, heat flowing through a solid and light travelling down an optical fibre are just three examples. How easily these quantities move inside a material depends on the resistance they experience, with collisions and friction slowing them down and making them fade away. This level of resistance largely determines whether the material is classed as an insulator, a conductor or a superconductor.
The mechanisms behind such transport fall into two main categories. The first is ballistic transport, which features linear movement without loss, like a bullet travelling in a straight line. The second is diffusive transport, where the quantity is subject to many random collisions. A good example is heat conduction, where the heat moves through a material gradually, travelling in many directions at once.
Breaking the rules
Most systems are strongly affected by diffusion, which makes it surprising that the TU Wien researchers could build an atomic system where mass and energy flowed freely without it. According to study leader Frederik Møller, the key to this unusual behaviour is the magnetic and optical fields that keep the rubidium atoms confined to one dimension, “freezing out” interactions in the atoms’ two transverse directions.
Because the atoms can only move along a single direction, Møller explains, they transfer momentum perfectly, without scattering their energy as would be the case in normal matter. Consequently, the 1D atomic system does not thermalize despite being subject to thousands of collisions.
To quantify the transport of mass (charge) and energy within this system, the researchers measured quantities known as Drude weights, which are fundamental parameters that describe ballistic, dissipationless transport in solid-state environments. According to these measurements, the single-dimensional interacting bosonic atoms do indeed demonstrate perfect dissipationless transport. The results also agree with the generalized hydrodynamics (GHD) theoretical framework, which describes the large-scale, inhomogeneous dynamics of one-dimensional integrable quantum many-body systems such as ultracold atomic gases or specific spin chains.
A Newton’s cradle for atoms
According to team leader Jörg Schmiedmayer, the experiment is analogous to a Newton’s cradle toy, which consists of a row of metal balls suspended on wires (see below). When the ball on one end of the row is made to collide with the one next to it, its momentum transfers straight through the other balls to the ball on the opposite end, which swings out. Schmiedmayer adds that the system makes it possible to study transport under perfectly controlled conditions and could open new ways of understanding how resistance emerges, or disappears, at the quantum level. “Our next steps are applying the method to strongly correlated transport and to transport in a topological fluid,” he tells Physics World.
Karèn Kheruntsyan, a theoretical physicist at the University of Queensland, Australia, who was not involved in this research, calls it “a significant step for studying quantum transport”. He says the team’s work clearly demonstrates ballistic (dissipationless) transport at a finite temperature, providing an experimental benchmark for theories of integrability and disorder. The work also validates the thermodynamic meaning of Drude weights, while confirming that linear-response theory and GHD accurately describe transport in quantum systems.
In Kheruntsyan’s view, though, the team’s biggest achievement is the quantitative extraction of Drude weights that characterize atomic and energy currents, with “excellent agreement” between experiment and theory. This, he says, shows truly ballistic transport in an interacting many-body system. One caveat, though, is that the system’s limited spatial resolution and near-ideal integrability prevent it from being used to explore diffusive regimes or stronger interaction effects, leaving microscopic dynamics such as dispersive shock waves unresolved.
Physics students from under-represented groups consistently report a lower sense of belonging at university than their over-represented peers. These students experience specific challenges that make them feel undervalued and excluded. Yet a strong sense of belonging has been shown to lead to improved academic performance, greater engagement in courses and better mental wellbeing. It is vital, then, that universities make changes to help eliminate these challenges.
Students are uniquely placed to describe the issues when it comes to belonging in physics. With this mind, as an undergraduate physics student with a passion for making the discipline more diverse and inclusive, I conducted focus groups with current and former physics students, interviewed experts and performed an analysis of current literature. This was part of a summer project funded by the Royal Institution and is currently being finalized for publication.
From this work it became clear that under-represented groups face many challenges to developing a strong sense of belonging in physics, but, at the same time, there are ways to improve the everyday experiences of students. When it comes to barriers, one is the widely held belief – reflected in the way physicists are depicted in the media and textbooks – that you need to be a “natural genius” to succeed in university physics. This notion hampers students from under-represented groups, who see peers from the over-represented majority appearing to grasp concepts more quickly and lecturers suggesting certain topics are “easy”.
The feeling that physics demands natural ability also arises from the so-called “weed out” culture, which is defined as courses that are intentionally designed to filter students out, reduce class sizes and diminish sense of belonging. Students who we surveyed believe that the high fail rate is caused by a disconnect between the teaching and workshops on the course and the final exam.
A third cause of this perception that you need some innate ability to succeed in physics is the attitudes and behaviour of some professors, lecturers and demonstrators. This includes casual sexist and racist behaviour; belittling students who ask for help; and acting as if they’re uninterested in teaching. Students from under-represented groups report significantly lower levels of respect and recognition from instructors, which damages their resilience and weakens sense of belonging.
Students from under-represented groups are also more likely to be isolated from their class mates and feel socially excluded from them. This means they lack a support network, leaving them with no-one to turn to when they encounter challenges. Outside the lecture theatre, students from under-represented groups typically face many microaggressions in their day-to-day university experience. These are subtle indignities or insults, unconsciously or consciously, towards minorities such as people of colour being told they “speak English very well”, male students refusing to accept women’s ideas, and the assumption that gender minorities will take on administrative roles in group projects.
Focus on the future
So what can be done? The good news is that there are many solutions to mitigate these issues and improve a sense of belonging. First, institutions should place more emphasis on small group “active learning” – which includes discussions, problem solving and peer-based learning. These pedagogical strategies have been shown to boost belonging, particularly for female students. After these active-learning sessions, non-academic, culturally sensitive social lunches can help turn “course friends” to “real friends” who choose to meet socially and can become a support network. This can help build connections within and between degree cohorts.
Another solution is for universities to invite former students to speak about their sense of belonging and how it evolved or improved throughout their degree. Hearing about struggles and learning tried-and-tested strategies to improve resilience can help students better prepare for stressful situations. Alumni are more relatable than generic messaging from the university wellbeing team.
Building closer links between students and staff also enhances a sense of belonging. It helps humanise lecturers and demonstrate that staff care about student wellbeing and success. This should be implemented by recognizing staff efforts formally so that the service roles of faculty members are formally recognized and professionalized.
Universities should also focus on hiring more diverse teaching staff, who can serve as role models, using their experiences to relate to and engage with under-represented students. Students will end up feeling more embedded within the physics community, improving both their sense of belonging and performance.
One practical way to increase diversity in hiring is for institutions to re-evaluate what they value. While securing large grants is valuable, so is advocating for equality, diversity and inclusion; public engagement; and the ability to inspire the next generation of physicists.
Another approach is to establish “departmental action teams” to find tailored solutions to unite undergraduates, postgraduates, teaching and research staff. Such teams identify issues specific to their particular university, and they can gather data through surveying the department to identify trends and recommend practical changes to boost belonging.
Implementing these measures will not only improve the sense of belonging for students from under-represented groups but also cultivate a more inclusive, diverse physics workforce. That in turn will boost the overall research culture, opening up research directions that may have previously been overlooked, and yielding stronger scientific outputs. It is crucial that we do more to support physics students from under-represented groups to create a more diverse physics community. Ultimately, it will benefit physics and society as a whole.
Luxembourg-based OQ Technology said Dec. 17 it has connected a commercial IoT chipset directly to one of its LEO satellites, using internally developed software based on 3GPP mobile standards.
The gyromagnetic ratio is the ratio of a particle’s magnetic moment and its angular momentum. This value determines how a particle responds to a magnetic field. According to classical physics, muons should have a gyromagnetic ratio equal to 2. However, owing to quantum mechanics, there is a small difference between the expected gyromagnetic ratio and the observed value. This discrepancy is known as the anomalous magnetic moment.
The anomalous magnetic moment is incredibly sensitive to quantum fluctuations. It can be used to test the Standard Model of physics, and previous consistent experimental discrepancies have hinted at new physics beyond the Standard Model. The search for the anomalous magnetic moment is one of the most precise tests in modern physics.
To calculate the anomalous magnetic moment, experiments such as Fermilab’s Muon g-2 experiment have been set up where researchers measure the muon’s wobble frequency, which is caused by its magnetic moment. But effects such as hadronic vacuum polarization and hadronic light-by-light scattering cause uncertainty in the measurement. Unlike hadronic vacuum polarization, hadronic light-by-light cannot be directly extracted from experimental cross-section data, making it dependent on the model used and a significant computational challenge.
In this work, the researcher took a major step in resolving the anomalous magnetic moment of the muon. Their method calculated how the neutral pion contributes to hadronic light-by-light scattering, used domain wall fermions to preserve symmetry, employed eight different lattice configurations with variational pion masses, and introduced a pion structure function to find the key contributions in a model-independent method. The pion transition form factor was computed directly at arbitrary space-like photon momenta, and a Gegenbauer expansion was used to confirm that about 98% of the π⁰-pole contribution was determined in a model-independent way. The analysis also included finite-volume corrections and chiral and continuum extrapolations and yielded a value for the π⁰ decay width.
The development of a more accurate and model-independent anomalous magnetic moment for the muon has reduced major theoretical uncertainties and can make Standard Model precision tests more robust.
Entanglement is a phenomenon where two or more particles become linked in such a way that a measurement on one of the particles instantly influences the state of the other, no matter how far apart they are. It is a defining property of quantum mechanics, which is key to all quantum technologies and remains a serious challenge to realize in large systems.
However, a team of researchers from Sweden and Spain has recently made a large step forward in the field of ultrafast entanglement. Here, pairs of extreme ultraviolet pulses are used to exert quantum control on the attosecond timescale (a few quintillionths of a second).
Specifically, they studied ultrafast photoionisation. In this process, a high-energy light pulse hits an atom, ejecting an electron and leaving behind an ion.
This process can create entanglement between the electron and the ion in a controlled way. However, the entanglement is fragile and can be disrupted or transferred as the system evolves.
For instance, as the newly-created ion emits a photon to release energy, the entanglement shifts from the electron – ion pair to the electron–photon pair. This transfer process takes a considerable amount of time, on the scale of 10s of nanoseconds. This means that the ion-electron pair is macroscopically separated, on the centimetre scale.
The team found that during this transition, all three particles – electron, ion, and photon – are entangled together in a multipartite state.
They did this by using a mathematical tool called von Neumann entropy to track how much information is shared between all three particles.
Although this work was purely theoretical, they also proposed an experimental method to study entanglement transfer. The setup would use two synchronised free-electron laser pulses, with attosecond precision, to measure the electron’s energy and to detect if a photon was emitted. By measuring both particles in coincidence, entanglement can be detected.
The results could be generalised to other scenarios and will help us understand how quantum information can move between different particles. This brings us one small step closer to future technologies like quantum communication and computing.
Learn how environmental constraints and a lack of soil led ancient bees to reuse fossil cavities in a Caribbean cave, leaving the first known evidence of this behavior.
Digantara Industries, an Indian space situational awareness company, has raised $50 million as it expands into the United States and pursues opportunities in missile defense.
Learn how decades of research suggest that everyday patterns in how people cope, organize their lives, and respond to stress may quietly shape long-term health.
Yale epidemiologist Harvey Risch, who has entertained a connection between Covid vaccines and “turbo cancer” and promoted ivermectin, says he'll chair the President's Cancer Panel.
In this episode of Space Minds, host Sandra Erwin sits down with former NASA astronaut and Space Force leader Brig. Gen. Nick Hague for a wide-ranging conversation on how the U.S. Space Force is shaping its culture, training Guardians, and preparing for future conflict in space.
Physicists searching for signs of quantum gravity have long faced a frustrating problem. Even if gravity does have a quantum nature, its effects are expected to show up only at extremely small distances, far beyond the reach of experiments. A new theoretical study by Benjamin Koch and colleagues at the Technical University of Vienna in Austria suggests a different strategy. Instead of looking for quantum gravity where space–time is tiny, the researchers argue that subtle quantum effects could influence how particles and light move across huge cosmical distances.
Their work introduces a new concept called q-desics, short for quantum-corrected paths through space–time. These paths generalize the familiar trajectories predicted by Einstein’s general theory of relativity and could, in principle, leave observable fingerprints in cosmology and astrophysics.
General relativity and quantum mechanics are two of the most successful theories in physics, yet they describe nature in radically different ways. General relativity treats gravity as the smooth curvature of space–time, while quantum mechanics governs the probabilistic behavior of particles and fields. Reconciling the two has been one of the central challenges of theoretical physics for decades.
“One side of the problem is that one has to come up with a mathematical framework that unifies quantum mechanics and general relativity in a single consistent theory,” Koch explains. “Over many decades, numerous attempts have been made by some of the most brilliant minds humanity has to offer.” Despite this effort, no approach has yet gained universal acceptance.
Deeper difficulty
There is another, perhaps deeper difficulty. “We have little to no guidance, neither from experiments nor from observations that could tell us whether we actually are heading in the right direction or not,” Koch says. Without experimental clues, many ideas about quantum gravity remain largely speculative.
That does not mean the quest lacks value. Fundamental research often pays off in unexpected ways. “We rarely know what to expect behind the next tree in the jungle of knowledge,” Koch says. “We only can look back and realize that some of the previously explored trees provided treasures of great use and others just helped us to understand things a little better.”
Almost every test of general relativity relies on a simple assumption. Light rays and freely falling particles follow specific paths, known as geodesics, determined entirely by the geometry of space–time. From gravitational lensing to planetary motion, this idea underpins how physicists interpret astronomical data.
Koch and his collaborators asked what happens to this assumption when space–time itself is treated as a quantum object. “Almost all interpretations of observational astrophysical and astronomical data rest on the assumption that in empty space light and particles travel on a path which is described by the geodesic equation,” Koch says. “We have shown that in the context of quantum gravity this equation has to be generalized.”
Generalized q-desic
The result is the q-desic equation. Instead of relying only on an averaged, classical picture of space–time, q-desics account for the underlying quantum structure more directly. In practical terms, this means that particles may follow paths that deviate slightly from those predicted by classical general relativity, even when space–time looks smooth on average.
Crucially, the team found that these deviations are not confined to tiny distances. “What makes our first results on the q-desics so interesting is that apart from these short distance effects, there are also long range effects possible, if one takes into account the existence of the cosmological constant,” Koch says.
This opens the door to possible tests using existing astronomical data. According to the study, q-desics could differ from ordinary geodesics over cosmological distances, affecting how matter and light propagate across the universe.
“The q-desics might be distinguished from geodesics at cosmological large distances,” Koch says, “which would be an observable manifestation of quantum gravity effects.”
Cosmological tensions
The researchers propose revisiting cosmological observations. “Currently, there are many tensions popping up between the Standard Model of cosmology and observed data,” Koch notes. “All these tensions are linked, one way or another, to the use of geodesics at vastly different distance scales.” The q-desic framework offers a new lens through which to examine such discrepancies.
So far, the team has explored simplified scenarios and idealized models of quantum space–time. Extending the framework to more realistic situations will require substantial effort.
“The initial work was done with one PhD student (Ali Riahina) and one colleague (Ángel Rincón),” Koch says. “There are many things to be revisited and explored that our to-do list is growing far too long for just a few people.” One immediate goal is to encourage other researchers to engage with the idea and test it in different theoretical settings.
Whether q-desics will provide an observational window into quantum gravity remains to be seen. But by shifting attention from the smallest scales to the largest structures in the cosmos, the work offers a fresh perspective on an enduring problem.
The Trump administration’s new national security strategy has rightly drawn criticism for presuming to tell our European allies how to arrange their domestic affairs. Equally as baffling is its near silence on a genuine United States national security concern — bolstering our offensive and defensive capabilities in space. Amid much MAGA trollery that blames Europe […]
SAN FRANCISCO – EraDrive, a Stanford University spinoff developing software and hardware for satellite autonomy, raised $5.3 million in an oversubscribed seed round, the startup announced Dec. 16. “EraDrive is very much about this idea of the self-driving spacecraft,” Justin Kruger, EraDrive chief technology officer and co-founder, told SpaceNews. EraDrive is developing a software-hardware module […]
A reported close approach between a Starlink satellite and a recently launched Chinese spacecraft highlights the challenges of coordinating spacecraft operations and verifying potential close calls in orbit.
Connexion
