The symmetries that govern the world of elementary particles at the most elementary level could be radically different from what has so far been thought. This surprising conclusion emerges from new work published by theoreticians from Warsaw and Potsdam. The scheme they posit unifies all the forces of nature in a way that is consistent with existing observations and anticipates the existence of new particles with unusual properties that may even be present in our close environs.
The coldest place beyond Earth is artificial, too. Last summer, astronauts activated an experiment called the Cold Atom Lab aboard the International Space Station. The lab has attained temperatures 30 million times lower than empty space. “I’ve been working on this idea, off and on, for over 20 years,” says Robert Thompson of NASA’s Jet Propulsion Lab, one of the researchers who devised the experiment. “It feels incredible to witness it up and operating.”
What happens when matter gets that cold?
If Thompson sounds excited, it’s because ultra-cold atoms behave in fascinating and potentially useful ways. For one thing, they lose their individual identities, fusing to form a bizarre state of matter called a Bose-Einstein condensate.
Magnetic fields around the Earth release strong bursts of energy, accelerating particles and feeding the auroras that glow in the polar skies. On July 11, 2017, four NASA spacecrafts were there to watch one of these explosions happen.
The process that produces these bursts is called magnetic reconnection, in which different plasmas and their associated magnetic fields interact, releasing energy. The Magnetospehric Multiscale Mission (MMS) satellites launched in 2015 to study the places where this reconnection process occurs. This newly released research shows for the first time that the mission encountered one of these reconnection sites in the night side of the Earth’s magnetic field, which extends behind the planet as a long “magnetotail.”
Researchers at the Center for Quantum Nanoscience (QNS) within the Institute for Basic Science (IBS) achieved a major breakthrough in shielding the quantum properties of single atoms on a surface. The scientists used the magnetism of single atoms, known as spin, as a basic building block for quantum information processing. The researchers could show that by packing two atoms closely together they could protect their fragile quantum properties much better than for just one atom.
The spin is a fundamental quantum mechanical object and governs magnetic properties of materials. In a classical picture, the spin often can be considered like the needle of a compass. The north or south poles of the needle, for example, can represent spin up or down. However, according to the laws of quantum mechanics, the spin can also point in both directions at the same time. This superposition state is very fragile since the interaction of the spin with the local environment causes dephasing of the superposition. Understanding the dephasing mechanism and enhancing the quantum coherence are one of the key ingredients toward spin-based quantum information processing.
In this study, published in the journal Science Advances in November 9, 2018, QNS scientists tried to suppress the decoherence of single atoms by assembling them closely together. The spins, for which they used single titanium atoms, were studied by using a sharp metal tip of a scanning tunneling microscope and the atoms’ spin states were detected using electron spin resonance. The researchers found that by bringing the atoms very close together (1 million times closer than a millimeter), they could protect the superposition states of these two magnetically coupled atoms 20 times longer compared to an individual atom.
Now scientists at the Large Hadron Collider (LHC) at Cern think they may have seen another particle, detected as a peak at a certain energy in the data, although the finding is yet to be confirmed. Again there’s a lot of excitement among particle physicists, but this time it is mixed with a sense of anxiety. Unlike the Higgs particle, which confirmed our understanding of physical reality, this new particle seems to threaten it.
The new result – consisting of a mysterious bump in the data at 28 GeV (a unit of energy) – has been published as a preprint on ArXiv. It is not yet in a peer-reviewed journal – but that’s not a big issue. The LHC collaborations have very tight internal review procedures, and we can be confident that the authors have done the sums correctly when they report a “4.2 standard deviation significance”. That means that the probability of getting a peak this big by chance – created by random noise in the data rather than a real particle – is only 0.0013%. That’s tiny – 13 in a million. So it seems like it must a real event rather than random noise – but nobody’s opening the champagne yet.