MIT researchers turned molecules into miniature colliders, allowing electrons to penetrate atomic nuclei and return clues about their internal structure. The breakthrough could expose hidden asymmetries that explain why matter exists at all.
Category: particle physics
Calorimetric experiment achieves tightest bound on electron neutrino mass
In a Physical Review Letters study, the HOLMES collaboration has achieved the most stringent upper bound on the effective electron neutrino mass ever obtained using a calorimetric approach, setting a limit of less than 27 eV/c² at 90% credibility.
This result validates a decades-old experimental vision and demonstrates the scalability needed for next-generation neutrino mass experiments.
While oscillation experiments have measured the differences between neutrino mass states, the actual individual mass values—the absolute neutrino mass scale—remain unknown. Pinning down these values would help complete our understanding of the Standard Model of particle physics.
Researchers realize a driven-dissipative Ising spin glass using a cavity quantum electrodynamics setup
Spin glasses are physical systems in which the small magnetic moments of particles (i.e., spins) interact with each other in a random way. These random interactions between spins make it impossible for all spins to satisfy their preferred alignments; a condition known as ‘frustration.
Researchers at Stanford University recently realized a new type of spin glass, namely a driven-dissipative Ising spin glass in a cavity quantum electrodynamics (QED) experimental setup. Their paper, published in Physical Review Letters, is the result of over a decade of studies focusing on creating spin glasses with cavity QED.
“Spin glasses are a general model for complex systems, and specifically for neural networks—spins serve as neurons connected by their mutually frustrating interactions,” Benjamin Lev, senior author of the paper, told Phys.org.
Sunlight split in two: Organic layer promises leap in solar power efficiency
In the race to make solar energy cheaper and more efficient, a team of UNSW Sydney scientists and engineers have found a way to push past one of the biggest limits in renewable technology.
Singlet fission is a process where a single particle of light—a photon—can be split into two packets of energy, effectively doubling the electrical output when applied to technologies harnessing the sun.
In a study appearing in ACS Energy Letters, the UNSW team—known as “Omega Silicon”—showed how this works on an organic material that could one day be mass-produced specifically for use with solar panels.
Physicists discover strange spinning crystals that behave like living matter
Spinning crystals that twist, shatter, and rebuild themselves may hold the key to next-generation materials… Physicists have uncovered the fascinating world of “rotating crystals” — solids made of spinning particles that behave in strange, almost living ways. These odd materials can twist instead of stretch, shatter into fragments, and even reassemble themselves.
‘Singing’ electrons synchronize in Kagome crystals, revealing geometry-driven quantum coherence
Physicists at the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) in Hamburg have discovered a striking new form of quantum behavior. In star-shaped Kagome crystals—named after a traditional Japanese bamboo-basket woven pattern—electrons that usually act like a noisy crowd suddenly synchronize, forming a collective “song” that evolves with the crystal’s shape. The study, published in Nature, reveals that geometry itself can tune quantum coherence, opening new possibilities to develop materials where form defines function.
Quantum coherence—the ability of particles to move in synchrony like overlapping waves—is usually limited to exotic states such as superconductivity, where electrons pair up and flow coherently. In ordinary metals, collisions quickly destroy such coherence.
But in the Kagome metal CsV₃Sb₅, after sculpting tiny crystalline pillars just a few micrometers across and applying magnetic fields, the MPSD team observed Aharonov–Bohm-like oscillations in electrical resistance. Thus showing that electrons were interfering collectively, remaining coherent far beyond what single-particle physics would allow.
Seeking Signatures of Graviton Emission and Absorption
A proposed experiment may deliver evidence for the emission or absorption of gravitons—an advance that might one day enable gravity to be controlled much like electromagnetism is today.
A major milestone in human development was the transition from passively observing electromagnetic phenomena, such as electric discharges and magnetism, to actively manipulating them. This shift led to a plethora of applications—from power plants to modern electronics. The exquisite control of electromagnetic fields and of their interaction with matter has also yielded deep insights into the fundamental laws of nature, allowing us to test modern theories with remarkable precision. Now Ralf Schützhold of the Helmholtz-Zentrum Dresden-Rossendorf in Germany argues that a similar turning point may be reached for gravity [1]. His approach for manipulating gravity relies on experiments that can control the emission or absorption of gravitons, the hypothetical elementary particles mediating the gravitational interaction in a quantized theory of gravity.
AI efficiency advances with spintronic memory chip that combines storage and processing
To make accurate predictions and reliably complete desired tasks, most artificial intelligence (AI) systems need to rapidly analyze large amounts of data. This currently entails the transfer of data between processing and memory units, which are separate in existing electronic devices.
Over the past few years, many engineers have been trying to develop new hardware that could run AI algorithms more efficiently, known as compute-in-memory (CIM) systems. CIM systems are electronic components that can both perform computations and store information, typically serving both as processors and non-volatile memories. Non-volatile essentially means that they can retain data even when they are turned off.
Most previously introduced CIM designs rely on analog computing approaches, which allow devices to perform calculations leveraging electrical current. Despite their good energy efficiency, analog computing techniques are known to be significantly less precise than digital computing methods and often fail to reliably handle large AI models or vast amounts of data.
Mirrorless laser: Physicists propose a new light source
A team of physicists from the University of Innsbruck and Harvard University has proposed a fundamentally new way to generate laser light: a laser without mirrors. Their study, published in Physical Review Letters, shows that quantum emitters spaced at subwavelength distances can constructively synchronize their photon emission to produce a bright, very narrow-band light beam, even in the absence of any optical cavity.
In conventional lasers, mirrors are essential to bounce light back and forth, stimulating coherent emission from excited atoms or molecules, and thus light amplification. But in the new “mirrorless” concept, the atoms interact directly through their own electromagnetic dipole fields, given that interatomic spacing is smaller than the emitted light’s wavelength. When the system is pumped with enough energy, these interactions cause the emitters to lock together and radiate collectively—a phenomenon called superradiant emission.
The team led by Helmut Ritsch found that this collective emission generates light that is both highly directional and spectrally pure, with a single narrow spectral line, in cases where only a fraction of emitters are excited by a laser and the rest of atoms remain unpumped. Since this passive emitter fraction is not broadened by the driving laser or power broadening, it effectively acts as an optical resonator for the active emitters, in analogy with a conventional laser where the optical resonator and the gain medium are separate physical entities.