Using atoms in two different highly excited states enables quantum bits that are both long-lived and manipulable.
Category: particle physics
What if the direction of a magnet could shape the building blocks of life?
In a new discovery, researchers from the Hebrew University of Jerusalem and the Weizmann Institute of Science have found that something in the direction of a magnetic field can influence how molecules of life behave at the most fundamental level and how early chemical processes linked to life may have unfolded.
The study, published in Chem and led by Prof. Yossi Paltiel (Hebrew University) and Prof. Michal Sharon (Weizmann Institute), shows that tiny differences between atoms (different isotopes) can lead to measurable changes in molecular behavior when combined with an invisible quantum property known as electron spin. Separation of the different isotopes can be achieved by magnetic surfaces.
At the center of the story is L-methionine, an amino acid, a basic building block of life. Like other biological molecules, methionine has a specific “handedness,” meaning it exists in a form that is not identical to its mirror image. This property, called chirality, is a mystery: why did nature choose one “hand” over the other?
The complete evolution of spin glass from order to chaos
How come our universe is full of disorder, when all elementary particles appear to follow strictly ordered laws of physics? And are there organizing principles behind disorder and apparent chaos?
One avenue of studying these fundamental questions is through an assembly of spins: the quantum property that makes electrons behave like tiny bar magnets, with a preferred orientation of either up or down. Neighboring spins align either in parallel (up-up) or antiparallel (up-down-up-down), as in ferromagnets and antiferromagnets, respectively. This simple ruleset makes spin systems very attractive for studying the emergence of order.
However, while the theory of spin is well-established, creating the material conditions for observing spin disorder has proven notoriously elusive. While physicists have been able to create exotic materials that exhibit spin disorder, tracing the evolution from order to disorder within materials has been challenged by the lack of a clean starting point.
Physicists confirm ‘negative time’ is real by asking the atoms themselves
A new experiment confirms that photons passing through a cloud of atoms can spend a negative amount of time there, and the atoms themselves are the ones saying so.
Researchers measure giant light-conversion effect in chiral carbon nanotubes
A sheet of twisted carbon nanotubes has revealed a hidden talent scientists suspected for decades but had never managed to measure.
Researchers at Rice University have created large, highly ordered films of chiral carbon nanotubes (CNTs), hollow cylinders of carbon atoms with either a left-or a right-handed twist. Measurements showed the crystalline films can convert the color of light at a rate two to three orders of magnitude greater than conventional materials.
The findings, reported in a study published in ACS Nano, confirm a long-standing theoretical prediction and point toward a future in which ultrathin carbon nanotube films could help power faster optical communications, flexible photonic chips and light-based computing systems that today exist mostly as prototypes.
Tritium-infused graphene could sharpen the hunt for neutrino mass
While neutrinos are some of the most abundant particles in the universe, they remain among the least understood. One of the biggest puzzles is their mass: although experiments have shown that neutrinos must have some mass, pinning down exactly how much has proven extraordinarily difficult.
Now, a team of physicists led by Valentina Tozzini of the Institute of Nanoscience in Pisa have published new theoretical calculations in Physical Review C, suggesting that tritium-infused graphene could give future experiments a decisive edge in measuring neutrino masses with unprecedented precision.
New chip offers way to make use of quantum system ‘imperfections’
Quantum technologies promise powerful new kinds of computers, giving scientists new tools to mimic and explore nature at its tiniest scales. At those levels, everything in nature—from atoms and electrons to light itself—follows the strange rules of quantum mechanics. But the real world is never perfectly clean: Signals fade, energy leaks away and systems pick up noise from their surroundings.
“Understanding how quantum systems behave under this messiness is crucial if we want our experiments to say something about nature as it really is, not just idealized setups,” says Govind Krishna, Ph.D. student at KTH Royal Institute of Technology.
Overlooked ‘history force’ may skew particle motion by up to 60% in shaken fluids
Physicists at the University of Bayreuth have investigated the so-called Basset–Boussinesq history force acting on particles in fluids. Due to the difficulty of calculating it, this force is often neglected—a fact that Bayreuth doctoral researcher Frederik Gareis already identified as a secondary school pupil during a student research project with his supervisor. The researchers report their new findings on the history force in Physical Review Fluids.
When particles move in liquids or air with velocities that change over time, several forces act on them, including the often overlooked history force. It arises from the formation of vortices around accelerating particles in fluids. In this way, the surrounding fluid “remembers” previous particle motions and influences their subsequent movement.
“The history force is often ignored because it is mathematically complex and makes calculations significantly more demanding. It is frequently unclear whether neglecting it leads to larger errors in modeling particle motion in fluids,” says Frederik Gareis, a doctoral researcher at the Theoretical Physics I research group at the University of Bayreuth and first author of the study.
Beyond 0 and 1: Ferrotoroidic material can store four magnetic states
Today’s computers store information using only two values: 0 and 1. But as electronic devices become smaller and reach their limits, scientists are searching for new ways to pack more information into the same space. One idea is to use magnetism. In some materials, atoms behave like tiny magnets that can arrange themselves in different patterns. If each pattern represents a different value, one memory element could store more than just two possibilities.
In a study recently published in Nature Communications, researchers have found a material in which these atomic magnets can form four different magnetic states. They showed that these states can be controlled using electric and magnetic fields and remain stable once created.
Using neutron experiments at the Institut Laue-Langevin, the scientists were able to observe each of the four magnetic states that were created by applying electric and magnetic fields. This discovery hints at a future where computers might store significantly more information than today’s binary technologies.