Trapped atoms exhibit discrete step-like behavior across a barrier, mimicking the quantum tunneling behavior in superconducting circuits.
Category: particle physics – Page 3
Earth’s atmosphere may help support human life on the moon
The moon’s surface may be more than just a dusty, barren landscape. Over billions of years, tiny particles from Earth’s atmosphere have landed in the lunar soil, creating a possible source of life-sustaining substances for future astronauts. But scientists have only recently begun to understand how these particles make the long journey from Earth to the moon and how long the process has been taking place.
New research from the University of Rochester, published in Communications Earth & Environment, shows that Earth’s magnetic field may actually help guide atmospheric particles—carried by solar wind—into space, instead of blocking them. Because Earth’s magnetic field has existed for billions of years, this process could have steadily moved particles from Earth to the moon over very long periods of time.
“By combining data from particles preserved in lunar soil with computational modeling of how solar wind interacts with Earth’s atmosphere, we can trace the history of Earth’s atmosphere and its magnetic field,” says Eric Blackman, a professor in the Department of Physics and Astronomy and a distinguished scientist at URochester’s Laboratory for Laser Energetics (LLE).
Magic moments with John Bell
This was a monumental breakthrough in the philosophy and foundations of quantum mechanics. Bell derived a mathematical inequality that showed if there were any local “hidden variables” (underlying, deterministic factors) explaining the “spooky” correlations in quantum entanglement, those correlations would have to obey certain limits. Experiments inspired by his theorem (starting with Alain Aspect in the early 1980s) have repeatedly shown that these limits are violated, confirming that quantum entanglement is real, non-local, and that nature fundamentally disagrees with Einstein’s idea of “local realism.”
John Bell, with whom I had a fruitful collaboration and warm friendship, is best known for his seminal work on the foundations of quantum physics, but he also made outstanding contributions to particle physics and accelerator physics.
Neutrino observatories show promise for detecting light dark matter
Dark matter is an elusive type of matter that does not emit, reflect or absorb light, yet is estimated to account for most of the universe’s mass. Over the past decades, many physicists worldwide have been trying to detect this type of matter or signals associated with its presence, employing various approaches and technologies.
As it has never been directly detected before, the composition and properties of dark matter remain mostly unknown. Initially, dark matter searches focused on the detection of relatively heavy particles. More recently, however, physicists also started looking for lighter particles with masses below one giga-electron-volt (GeV), which would thus be lighter than protons.
Researchers at SLAC National Accelerator Laboratory and The Ohio State University recently showed that signatures of these sub-GeV dark matter particles could also be picked up by neutrino observatories, large underground detectors originally designed to study neutrinos (i.e., light particles that weakly interact with regular matter).
Ghostly solar neutrinos caught transforming carbon atoms deep underground
Neutrinos are one of the most mysterious particles in the universe, often called “ghost particles” because they rarely interact with anything else. Trillions stream through our bodies every second, yet leave no trace. They are produced during nuclear reactions, including those that take place in the core of our sun.
Their tendency to not interact often makes detecting neutrinos notoriously difficult. Neutrinos from the sun have only been seen to interact on a handful of different targets. Now, for the first time, scientists have succeeded in observing them transform carbon atoms into nitrogen inside a vast underground detector.
ALICE solves mystery of light-nuclei survival
Observations of the formation of light-nuclei from high-energy collisions may help in the hunt for dark matter.
Particle collisions at the Large Hadron Collider (LHC) can reach temperatures over one hundred thousand times hotter than at the center of the sun. Yet, somehow, light atomic nuclei and their antimatter counterparts emerge from this scorching environment unscathed, even though the bonds holding the nuclei together would normally be expected to break at a much lower temperature.
Physicists have puzzled for decades over how this is possible, but now the ALICE collaboration has provided experimental evidence of how it happens, with its results published today in Nature.
An old jeweler’s trick could unlock next-generation nuclear clocks
In 2008, a team of UCLA-led scientists proposed a scheme to use a laser to excite the nucleus of thorium atoms to realize extremely accurate, portable clocks. Last year, they realized this longstanding goal by bombarding thorium atoms embedded in specialized fluoride crystals with a laser. Now, they have found a way to dramatically simplify and strengthen the process by replacing the specialized crystals with thorium electroplated onto steel.
They observe, for the first time, that laser excitation of the thorium nucleus in this system leads to a measurable electric current, which can be used to miniaturize the nuclear clock. The advance is needed for smaller, more efficient atomic clocks, which have long been sought to improve navigation, GPS, power grids, and communications. It will also allow for some of the tightest tests ever of fundamental physics.
The rhythm of swarms: Tunable particles synchronize movement like living organisms
A collaboration between the University of Konstanz and Forschungszentrum Jülich has achieved the first fully tunable experimental realization of a long predicted “swarmalator” system. The study, published in Nature Communications, shows how tiny, self-propelled particles can simultaneously coordinate their motion and synchronize their internal rhythms—a behavior reminiscent of flashing fireflies, Japanese tree frogs or schooling fish.
The results underline how collective dynamics can arise from simple interactions, without overarching leadership or control. Possible applications include autonomous robotic swarms.
Swarmalators—short for swarming oscillators—are systems in which each individual not only moves but also oscillates, with motion and rhythm influencing one another.