Lifeboat Foundation

The world of the very, very small is a wonderland of strangeness. Molecules, atoms, and their constituent particles did not readily reveal their secrets to the scientists that wrestled with the physics of atoms in the early 20th century. Drama, frustration, anger, puzzlement, and nervous breakdowns abounded, and it is hard for us now, a full century later, to understand what was at stake. What happened was a continuous process of worldview demolition. You might have to give up believing everything you thought to be true about something. In the case of the quantum physics pioneers, that meant changing their understanding about the rules that dictate how matter behaves.

In 1913, Bohr devised a model for the atom that looked somewhat like a solar system in miniature. Electrons moved around the atomic nucleus in circular orbits. Bohr added a few twists to his model — twists that gave them a set of weird and mysterious properties. The twists were necessary for Bohr’s model to have explanatory power — that is, for it to be able to describe the results of experimental measurements. For example, electrons’ orbits were fixed like railroad tracks around the nucleus. The electron could not be in between orbits, otherwise it could fall into the nucleus. Once it got to the lowest rung in the orbital ladder, an electron stayed there unless it jumped to a higher orbit.

Clarity about why this happened started to come with de Broglie’s idea that electrons can be seen both as particles and waves. This wave-particle duality of light and matter was startling, and Heisenberg’s uncertainty principle gave it precision. The more precisely you localize the particle, the less precisely you know how fast it moves. Heisenberg had his own theory of quantum mechanics, a complex device to compute the possible outcomes of experiments. It was beautiful but extremely hard to calculate things with.

In a first, physicists have now found interference between two dissimilar subatomic particles. Researchers made the observation at the Relativistic Heavy Ion Collider (RHIC), a colossal particle accelerator at Long Island’s Brookhaven National Laboratory. The finding broadens the way we understand entanglement and offers new opportunities to use it to study the subatomic world.

“With this new technique, we are able to measure the size and shape of the nucleus to about a tenth of a femtometer, a tenth of the size of an individual proton,” says James Daniel Brandenburg, a physicist at the Ohio State University and a member of RHIC’s STAR experiment, where the new phenomenon was seen. That’s 10 to 100 times more precise than previous measurements of high-energy atomic nuclei.

RHIC is designed to collide heavy ions, such as the nuclei of gold atoms. In this case, though, researchers were interested in near misses, not collisions. As the gold nuclei zing at near light speed through the collider, they create an electromagnetic field that generates photons. When two gold nuclei come close to one another but don’t collide, the photons may ping off the neighboring nuclei. These near misses used to be considered background noise, says STAR collaborator Raghav Kunnawalkam Elayavalli, a physicist at Vanderbilt University. But looking at the close-call events “opened up a whole new field of physics that initially was not accessible,” Kunnawalkam Elayavalli says.

“Suppose you knew everything there was to know about a water molecule—the chemical formula, the bond angle, etc.,” says Joseph Thywissen, a professor in the Department of Physics and a member of the Centre for Quantum Information & Quantum Control at the University of Toronto.

“You might know everything about the molecule, but still not know there are waves on the ocean, much less how to surf them,” he says. “That’s because when you put a bunch of molecules together, they behave in a way you probably cannot anticipate.”

Thywissen is describing the concept in physics known as emergence: the relationship between the behavior and characteristics of individual particles and large numbers of those particles. He and his collaborators have taken a first step in understanding this transition from “one-to-many” particles by studying not one, not many, but two isolated, interacting particles, in this case potassium atoms.

For the first time, scientists have performed an iconic physics experiment with a positron — the antimatter counterpart of an electron, one of the fundamental particles.

Not only did they get some truly interesting results, but this achievement could become the first step towards potentially revolutionary discoveries.

The experiment — an antimatter version of the famous double-slit setup — was carried out by researchers from Switzerland and Italy in order to lay the groundwork for a novel line of super-sensitive experiments that might help solve a mystery concerning the Universe’s two domains of matter.

This week our guest is Meghan O’Gieblyn, who has written regularly for entities such as Wired, The New York Times, and The Guardian, in addition to authoring books such as Interior States and her latest book: God, Human, Animal, Machine: Technology, Metaphor, and the Search for Meaning.

Interestingly, much of Meghan’s work pulls on her experience losing her faith in religion while simultaneously being drawn into transhumanism from reading the Age of Spiritual Machines by Singularity’s very own Ray Kurzweil. This exploration of Meghan’s background and her latest book takes us on a journey through the ways in which technology and spirituality have historically woven together, the current ways in which they are conflicting, and the future philosophical questions we’re going to be forced to reconcile. For those of you interested in this subject, I highly recommend going and listening to episode 52 with Micah Redding, which lays a lot of the foundation that we build on her in this episode.

Continue reading “God, Human, Animal, & Machine | Meghan O’Gieblyn, Feedback Loop ep 54” »

The difference between predictions and observations of the magnetic properties of muons suggests a mystery for the Standard Model.

In June 2021, NASA’s Juno spacecraft flew close to Ganymede, Jupiter’s largest moon, observing evidence of magnetic reconnection. A team led by Southwest Research Institute used Juno data to examine the electron and ion particles and magnetic fields as the magnetic field lines of Jupiter and Ganymede merged, snapped and reoriented, heating and accelerating the charged particles in the region.

“Ganymede is the only moon in our solar system with its own magnetic field,” said Juno Principal Investigator Dr. Scott Bolton of SwRI. “The snapping and reconnecting of Ganymede’s magnetic field lines with Jupiter’s creates the magnetospheric fireworks.”

Magnetic reconnection is an explosive physical process that converts stored magnetic energy into kinetic energy and heat. Ganymede’s mini-magnetosphere interacts with Jupiter’s massive magnetosphere, in the magnetopause, the boundary between the two regions.

One of the biggest achievements of quantum physics was recasting our vision of the atom. Out was the early 1900s model of a solar system in miniature, in which electrons looped around a solid nucleus. Instead, quantum physics showed that electrons live a far more interesting life, meandering around the nucleus in clouds that look like tiny balloons. These balloons are known as atomic orbitals, and they come in all sorts of different shapes—perfectly round, two-lobed, clover-leaf-shaped. The number of lobes in the balloon signifies how much the electron spins about the nucleus.

That’s all well and good for individual atoms, but when atoms come together to form something solid—like a chunk of metal, say—the outermost electrons in the atoms can link arms and lose sight of the nucleus from where they came, forming many oversized balloons that span the whole chunk of metal. They stop spinning about their nuclei and flow through the metal to carry electrical currents, shedding the diversity of multi-lobed balloons.

Now, researchers at the Quantum Materials Center (QMC) at the University of Maryland (UMD), in collaboration with theorists at the Condensed Matter Theory Center (CMTC) and Joint Quantum Institute (JQI), have produced the first experimental evidence that one metal—and likely others in its class—have electrons that manage to preserve a more interesting, multi-lobed structure as they move around in a solid. The team experimentally studied the shape of these balloons and found not a uniform surface, but a complex structure. This unusual metal is not only fundamentally interesting, but it could also prove useful for building quantum computers that are resistant to noise.

Several experiments have been set up outside nuclear reactors to record escaping antineutrinos. The data generally agrees with theory, but at certain energies, the antineutrino flux is 6–10% above or below predictions. These so-called reactor antineutrino anomalies have excited the neutrino community, as they could be signatures of a hypothetical sterile neutrino (see Viewpoint: Getting to the Bottom of an Antineutrino Anomaly). But a new analysis by Alain Letourneau from the French Atomic Energy Commission (CEA-Saclay) and colleagues has shown that the discrepancies may come from experimental biases in associated electron measurements [1].

The source of reactor antineutrinos is beta decay, which occurs in a wide variety of nuclei (more than 800 species in a typical fission reactor). To predict the antineutrino flux, researchers have typically used previously recorded data on electrons, which are also produced in the same beta decays. This traditional method takes the observed electron spectra from nuclei, such as uranium-235 and plutonium-239, and converts them into predicted antineutrino spectra. But Letourneau and colleagues have found reason to doubt the electron measurements.

The team calculated antineutrino spectra—as well as the corresponding electron spectra—using a fundamental theory of beta decay. This method works for some nuclei, but not all, so the researchers plugged the gaps using a phenomenological model. They were able to treat all 800-plus reactor beta decays, finding “bumps” in the antineutrino flux that agree with observations. Similar features are predicted for electron spectra, but they don’t show up in the data. The results suggest that an experimental bias in electron observations causes the reactor antineutrino anomalies. To confirm this hypothesis, the researchers call for new precision measurements of the fission electrons.