Researchers at Delft University of Technology (the Netherlands) have succeeded in controlling the magnetism in the nucleus of a single atom with radio waves. This came as a surprise: until now, physicists believed that this nuclear spin could not be manipulated directly. The discovery could open up new possibilities for storing and reading quantum information. The research is published in the journal Nature Communications.

In metals such as iron and nickel, every atom is slightly magnetic. But inside the atom, different magnetic "compass needles," known in quantum mechanics as spins, are also at work. "By far the strongest magnetism comes from the electrons," says lead researcher Sander Otte. "But in some atoms, the nucleus also carries a spin. That spin is much weaker, but it is also much better shielded from the outside world."

Otte's group studies spins using a converted scanning tunneling microscope. This enables electrical signals to be directed with extreme precision at a single atom. In the past, the researchers mainly focused on the electron spin, which is the easiest to read out. The nuclear spin appeared only indirectly, through the so-called hyperfine interaction. This causes the spins of the nucleus and the electron to become slightly entangled.

Control against expectations
In their latest experiment, main author Hester Vennema and her colleagues sent two different signals to an atom simultaneously: one targeting the electron and one targeting the nucleus. This allowed them to study the influence of each signal independently. To their surprise, they found that they could flip the nuclear spin even when the two spins were largely disentangled.

That result came unexpectedly. "According to our simple understanding, this should not really happen," says Otte. "The nuclear spin should not be sensitive at all to the electrical signals from a scanning tunneling microscope." ...

The theory that comets delivered the molecular building blocks for life on Earth is a long-standing one, since comets are known to carry many of these molecules. However, a new study challenges this idea.

The researchers, led by the University of Cambridge, found the cometary delivery of these building blocks would be—at best—a 'one-off fluke,' and not the steady rain of prebiotic molecules that had been theorized.

Using computer modeling, the researchers determined that comets travel too fast and at too sharp an angle to Earth's atmosphere for the fragile organic molecules to survive: they would almost certainly vaporize on impact with the surface. However, the researchers also found that another planet in our system—Mars—could be a slightly more promising candidate for cometary delivery of prebiotic molecules, although this is still highly unlikely. The results are published in the journal Scientific Reports.

"Historically, scientists thought that comets were important for the origin of life on Earth, because they carried carbon- and nitrogen-bearing molecules, so these giant space snowballs were almost like a 'get out of jail free card' that brought all the molecules a planet would need to seed life," said lead author Dr. Richard Anslow from Cambridge's Institute of Astronomy. "It's kind of a romantic idea, but our results suggest it's highly unlikely."

Testing the planet-hopping comet theory
In 2023, Anslow and several of his co-authors on the current paper theorized that in systems where planets orbit closely together, comets might slow down by 'bouncing' from one planet to the next, delivering organic molecules as they went.

Building on the earlier study, Anslow and his colleagues investigated whether such a scenario might be possible in our own solar system. "We're learning more and more all the time about how our solar system and the Earth formed, and pulling this together with lots of different advances in modeling, which allowed us to investigate this idea that has been around for close to a century," he said.

However, the new study shows just how rare that scenario is. The researchers used recent advances in comet impact simulations, comet-atmosphere interactions and dynamic modeling of the origin and evolution of comets to conduct their study. Taken together, the researchers found that while the successful delivery of prebiotic molecules cannot be ruled out completely, it would be extremely unlikely...

Many of the world's leading happiness researchers say they consciously spend more time with loved ones after seeing the evidence, according to a new paper. "Happiness emerges from a symphony of factors, but if I had to pinpoint one secret to happiness, relationships with other people might be it," says Lara Aknin, a professor of social psychology at Simon Fraser University.

Earlier this year, Aknin took part in a Zoom call with 12 other international leaders in well-being science. On the agenda? What their collective 600 years of happiness research and their own lived experiences reveal about living a good life and the future of the field they helped to create. Their reflections were captured in a recent paper published in the Journal of Happiness Studies.

"Having relationships is one of the most reliable predictors of happiness that has emerged from a robust body of evidence spanning the social sciences," says Aknin, who coauthored the paper with Harvard University's Säde Stenlund and Kelsey O'Connor, a senior researcher at Luxembourg's National Institute of Statistics and Economic Studies.

"We know that having just one person you can count on is extremely consequential. Having more relationships and more communities that you feel a part of compounds that sense of well-being."

Researchers also talked about well-being as a journey, says Aknin. Generally happy people aren't constantly happy, nor is happiness reserved only for people with ideal lives, perfect circumstances or a natural sense of optimism. Instead, it can be developed through conscious choices, self-awareness and adaptation, even when life gets hard, she says.

Some of the leading models on happiness suggest that roughly 10% of one's happiness is attributable to one's life circumstances—things that are big and relatively difficult to change, like where you live, your age, your employment status or your relationship status. But as much as 40% of one's happiness is related to "volitional activities" or how you choose to spend your time...