Quantum ideas describe particles and fields in tiny packages, but general relativity paints gravity as smooth curves in space‑time. Until now.
Category: particle physics – Page 25
New Physics Theory Says Spacetime “Dissolves” at Super Small Scales
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New physics theory claims spacetime dissolves and particles get super small.
A Glimpse at the Quantum Behavior of a Uniform Gas
An innovative way to image atoms in cold gases could provide deeper insights into the atoms’ quantum correlations.
The macroscopic properties of objects that we encounter in everyday life are ultimately determined by the behavior of these objects’ microscopic constituents. For instance, the way that atoms move is key to understanding the pressure of the gas in our tires or the flow of our morning coffee into a cup. However, equally important is how the positions of these particles are correlated—how the particles “dance” together. This dance has already been imaged in highly confined systems in which particles can move only between discrete sites [1]. Now three separate experimental groups, one from École Normale Supérieure in Paris and two from MIT, have imaged the positions of individual atoms in a cold, uniform gas, exposing the atoms’ quantum correlations [2– 4].
The fundamental quantum nature of particles leads to counterintuitive behavior in a collection of particles, even if there are no forces acting between them. Because quantum particles are indistinguishable, the probability of detecting one at a particular position is independent of which particle is observed. This feature implies that there are two classes of particle: bosons, which can change places without affecting the system’s quantum state; and fermions, which flip the sign of the state upon their exchange. The result is that photons and other bosons tend to bunch together, whereas electrons and other fermions tend to avoid each other.
Quantum effects in proteins: How tiny particles coordinate energy transfer inside cells
Protons are the basis of bioenergetics. The ability to move them through biological systems is essential for life. A new study in Proceedings of the National Academy of Sciences shows for the first time that proton transfer is directly influenced by the spin of electrons when measured in chiral biological environments such as proteins. In other words, proton movement in living systems is not purely chemical; it is also a quantum process involving electron spin and molecular chirality.
The quantum process directly affects the small movements of the biological environment that support proton transfer. This discovery suggests that energy and information transfer in life is more controlled, selective, and potentially tunable than previously believed, bridging quantum physics with biological chemistry and opening new doors for understanding life at its deepest level—and for designing technologies that can mimic or control biological processes.
The work, led by a team of researchers from the Hebrew University of Jerusalem collaborating with Prof. Ron Naaman from Weizmann Institute of Science and Prof. Nurit Ashkenasy from Ben Gurion University, reveals a surprising connection between the movement of electrons and protons in biological systems.
Shortcut in ‘magnetic bottles’ design offers an answer to a complex 70-year-old fusion challenge
Abundant, low-cost, clean energy—the envisioned result if scientists and engineers can successfully produce a reliable method of generating and sustaining fusion energy—has taken one step closer to reality, as a team of researchers from the University of Texas at Austin, Los Alamos National Laboratory and Type One Energy Group has solved a longstanding problem in the field.
One of the big challenges holding fusion energy back has been the ability to contain high-energy particles inside fusion reactors. When high-energy alpha particles leak from a reactor, that prevents the plasma from getting hot and dense enough to sustain the fusion reaction. To prevent them from leaking, engineers design elaborate magnetic confinement systems, but there are often holes in the magnetic field, and a tremendous amount of computational time is required to predict their locations and eliminate them.
In their paper published in Physical Review Letters, the research team describes having discovered a shortcut that can help engineers design leak-proof magnetic confinement systems 10 times as fast as the gold standard method, without sacrificing accuracy. While several other big challenges remain for all magnetic fusion designs, this advance addresses the biggest challenge that’s specific to a type of fusion reactor first proposed in the 1950s, called a stellarator.
New quantum theory of gravity brings long-sought ‘theory of everything’ a crucial step closer
At long last, a unified theory combining gravity with the other fundamental forces—electromagnetism and the strong and weak nuclear forces—is within reach. Bringing gravity into the fold has been the goal of generations of physicists, who have struggled to reconcile the incompatibility of two cornerstones of modern physics: quantum field theory and Einstein’s theory of gravity.
Researchers at Aalto University have developed a new quantum theory of gravity which describes gravity in a way that’s compatible with the standard model of particle physics, opening the door to an improved understanding of how the universe began.
While the world of theoretical physics may seem remote from applicable tech, the findings are remarkable. Modern technology is built on such fundamental advances—for example, the GPS in your smartphone works thanks to Einstein’s theory of gravity.
Hours-long continuous lasing achieved using laser-cooled strontium atoms
Laser-cooled atomic gases, gases of atoms chilled to temperatures around absolute zero using laser technologies, have proved to be versatile physical platforms to study and control quantum phenomena. When these atomic gases interact with light inside an optical cavity (i.e., a structure designed to trap and enhance light), they can give rise to effects that can be leveraged to realize quantum sensing or simulate complex quantum systems.
Using atomic gases loaded in optical cavities, physicists have observed various intriguing effects, including self-organization phase transitions, characterized by the spontaneous arrangement of the gas atoms into ordered patterns, lasing and the preservation of quantum coherence. Generally, however, these effects are only observed for short times, as new atoms need to be reloaded in the cavity for them to be produced again.
Researchers at JILA, a joint research institute of the University of Colorado-Boulder and the National Institute of Standards and Technology, recently demonstrated continuous lasing that lasted hours using laser-cooled strontium-88 (88 Sr) atoms loaded into a ring (i.e., circular) optical cavity. Their paper, published in Nature Physics, could open new possibilities for the development of ultra-quiet lasers, as well as quantum computers and sensing technologies.
On-demand Lewis base formation strategy boosts efficiency and stability of perovskite solar cells
Solar cells based on perovskites, materials with a characteristic crystal structure first unveiled in the mineral calcium titanate (CaTiO3), have emerged as a promising alternative to conventional silicon-based photovoltaics. A key advantage of these materials is that they could yield high power conversion efficiencies (PCEs), yet their production costs could be lower.
Perovskite films can exist in different structural forms, also referred to as phases. One is the so-called α-phase (i.e., a photoactive black phase), which is the most desirable phase for the efficient absorption of light and the transport of charge carriers. The δ-phase, on the other hand, is an intermediate phase characterized by a different atom arrangement and reduced photoactivity.
Researchers at the University of Toledo, Northwestern University, Cornell University and other institutes recently introduced a new strategy to control the crystallization process in perovskite-based solar cells, stabilizing the δ-phase while facilitating their transition to the α-phase. Their proposed approach, outlined in a paper in Nature Energy, enables the formation of Lewis bases on perovskites on demand to optimize crystallization, which can enhance the efficiency and stability of solar cells.
New era of magnetization: Research sheds light on future applications in spintronics and valleytronics
Altermagnets, which exhibit momentum-dependent spin splitting without spin–orbit coupling (SOC) or net magnetization, have recently attracted significant international attention.
A team led by Prof. Liu Junwei from the Department of Physics at the Hong Kong University of Science and Technology (HKUST), along with their experimental collaborators, published their latest research findings in Nature Physics, which unveiled the first experimental observation of a two-dimensional layered room-temperature altermagnet, validating the theoretical predictions in Nature Communications made by Prof. Liu in 2021.
The realization and control of spin-polarized electronic states in solids are crucial for spintronics for encoding and processing information. Spin polarization is typically generated by coupling an electron’s spin to other degrees of freedom, such as orbital or magnetic moments.