Researchers predict a large “CP” violation for the decay of a baryon that contains a bottom quark, a finding that has implications for how physicists understand the Universe.
Molecular “kicks” induced by ultraviolet light are predicted to cause carbon monoxide molecules to be released from the icy layers that cover cosmic dust.
Researchers have developed an atom-diffraction imaging method with micrometer spatial resolution, which may allow new applications in material characterization.
Microscopy with atoms offers new possibilities in the study of surfaces and two-dimensional (2D) materials [1]. Atom beams satisfy the most important requirements for microscopic probing: they can achieve high contrast and surface-specificity while doing little damage to the sample. A subtype of atomic microscopy—atomic-diffraction imaging—obtains measurements in reciprocal, or momentum, space, which is ideal for studying the surfaces of large and uniform crystalline samples. However, scientists developing this technique face challenges in achieving micrometer-scale spatial resolutions that would allow the study of polycrystalline materials, nonuniform 2D materials, and other surfaces without long-range order.
Thought to make up 85% of matter in the universe, dark matter is nonluminous and its nature is not well understood. While normal matter absorbs, reflects, and emits light, dark matter cannot be seen directly, making it harder to detect. A theory called “self-interacting dark matter,” or SIDM, proposes that dark matter particles self-interact through a dark force, strongly colliding with one another close to the center of a galaxy.
In work published in The Astrophysical Journal Letters, a research team led by Hai-Bo Yu, a professor of physics and astronomy at the University of California, Riverside, reports that SIDM simultaneously can explain two astrophysics puzzles in opposite extremes.
“The first is a high-density dark matter halo in a massive elliptical galaxy,” Yu said. “The halo was detected through observations of strong gravitational lensing, and its density is so high that it is extremely unlikely in the prevailing cold dark matter theory. The second is that dark matter halos of ultra-diffuse galaxies have extremely low densities and they are difficult to explain by the cold dark matter theory.”
For the first time, a team of Princeton physicists have been able to link together individual molecules into special states that are quantum mechanically “entangled.” In these bizarre states, the molecules remain correlated with each other—and can interact simultaneously—even if they are miles apart, or indeed, even if they occupy opposite ends of the universe. This research was recently published in the journal Science.
“This is a breakthrough in the world of molecules because of the fundamental importance of quantum entanglement,” said Lawrence Cheuk, assistant professor of physics at Princeton University and the senior author of the paper. “But it is also a breakthrough for practical applications because entangled molecules can be the building blocks for many future applications.”
These include, for example, quantum computers that can solve certain problems much faster than conventional computers, quantum simulators that can model complex materials whose behaviors are difficult to model, and quantum sensors that can measure faster than their traditional counterparts.
Quantum bits are potentially powerful but notoriously error-prone. Now a Harvard team says it has found a way to prevent mistakes — by manipulating individual atoms with laser beams — making quantum processing much more efficient.
The idea that sprinkling rock dust on farmland can soak up atmospheric carbon will be tested at large scale thanks to a $57 million purchase from corporations including Stripe and Alphabet.
Researchers at universities in New York and Ningbo, China, say they have created tiny robots built from DNA that can reproduce themselves.
Such nanorobots could one day launch search-and-destroy missions against cancer cells within a human’s bloodstream without the need for surgery or collect toxic waste from the ocean.
The tiny mechanism is so small that 1,000 of them could fit into the width of a sheet of paper.
A proposed model unites quantum theory with classical gravity by assuming that states evolve in a probabilistic way, like a game of chance.
Physicists’ best theory of matter is quantum mechanics, which describes the discrete (quantized) behavior of microscopic particles via wave equations. Their best theory of gravity is general relativity, which describes the continuous (classical) motion of massive bodies via space-time curvature. These two highly successful theories appear fundamentally at odds over the nature of space-time: quantum wave equations are defined on a fixed space-time, but general relativity says that space-time is dynamic—curving in response to the distribution of matter. Most attempts to solve this tension have focused on quantizing gravity, with the two leading proposals being string theory and loop quantum gravity. But new theoretical work by Jonathan Oppenheim at University College London proposes an alternative: leave gravity as a classical theory and couple it to quantum theory through a probabilistic mechanism [1].
