The unambiguous discovery of a Wigner crystal relied on a novel technique for probing the insides of complex materials.
Category: physics – Page 220
US achieves laser-fusion record: what it means for nuclear-weapons research
Housed at Lawrence Livermore National Laboratory, the US$3.5-billion facility wasn’t designed to serve as a power-plant prototype, however, but rather to probe fusion reactions at the heart of thermonuclear weapons. After the United States banned underground nuclear testing at the end of the cold war in 1,992 the energy department proposed the NIF as part of a larger science-based Stockpile Stewardship Program, designed to verify the reliability of the country’s nuclear weapons without detonating any of them.
With this month’s laser-fusion breakthrough, scientists are cautiously optimistic that the NIF might live up to its promise, helping physicists to better understand the initiation of nuclear fusion — and thus the detonation of nuclear weapons. “That’s really the scientific question for us at the moment,” says Mark Herrmann, Livermore’s deputy director for fundamental weapons physics. “Where can we go? How much further can we go?”
Here Nature looks at the NIF’s long journey, what the advance means for the energy department’s stewardship programme and what lies ahead.
Volume 596 Issue 7873, 26 August 2021
Proteins are essential to life, and understanding their 3D structure is key to unpicking their function. To date, only 17% of the human proteome is covered by an experimentally determined structure. Two papers in this week’s issue dramatically expand our structural understanding of proteins. Researchers at DeepMind, Google’s London-based sister company, present the latest version of their AlphaFold neural network. Using an entirely new architecture informed by intuitions about protein physics and geometry, it makes highly accurate structure predictions, and was recognized at the 14th Critical Assessment of Techniques for Protein Structure Prediction last December as a solution to the long-standing problem of protein-structure prediction. The team applied AlphaFold to 20,296 proteins, representing 98.5% of the human proteome.
Physicists Discover New Electronic Phenomenon
Physics researchers at the University of North Florida’s Atomic LEGO Lab discovered a new electronic phenomenon they call “asymmetric ferroelectricity”. The research led by Dr. Maitri Warusawithana, UNF physics assistant professor, in collaboration with researchers at the University of Illinois and the Arizona State University, demonstrated this phenomenon for the first time in engineered two-dimensional crystals.
Einstein’s E=mc2 equation creates matter from light for first time
Albert Einstein’s most famous equation, E = mc2, used in the theory of general relativity, has been used to create matter from light, scientists have said in a new study.
Researchers from New York’s Brookhaven National Laboratory used the Department of Energy’s Relativistic Heavy Ion Collider (RHIC), ordinarily used for nuclear physics research, to speed up two gold ions that are positively charged, in a loop.
Exotic property of ‘ambidextrous’ crystals points to new magnetic phenomena
Researchers from Skoltech, KTH Royal Institute of Technology, and Uppsala University have predicted the existence of antichiral ferromagnetism, a nontrivial property of some magnetic crystals that opens the door to a variety of new magnetic phenomena. The paper was published in the journal Physical Review B.
Chirality, or handedness, is an extremely important fundamental property of objects in many fields of physics, mathematics, chemistry and biology; a chiral object cannot be superimposed on its mirror image in any way. The simplest chiral objects are human hands, hence the term itself. The opposite of chiral is achiral: a circle or a square are simple achiral objects.
Chirality can be applied to much more complex entities; for instance, competing internal interactions in a magnetic system can lead to the appearance of periodic magnetic textures in the structure that differ from their mirror images—this is called chiral ferromagnetic ordering. Chiral crystals are widely considered promising candidates for magnetic data storage and processing device realization as information can be encoded via their nontrivial magnetic textures.
An AI expert explains why it’s hard to give computers something you take for granted: Common sense
Quick – define common sense
Despite being both universal and essential to how humans understand the world around them and learn, common sense has defied a single precise definition. G. K. Chesterton, an English philosopher and theologian, famously wrote at the turn of the 20th century that “common sense is a wild thing, savage, and beyond rules.” Modern definitions today agree that, at minimum, it is a natural, rather than formally taught, human ability that allows people to navigate daily life.
Common sense is unusually broad and includes not only social abilities, like managing expectations and reasoning about other people’s emotions, but also a naive sense of physics, such as knowing that a heavy rock cannot be safely placed on a flimsy plastic table. Naive, because people know such things despite not consciously working through physics equations.