Seminar entitled “A minimal SM/LCDM cosmology”, given by Neil Turok (University of Edinburgh and Perimeter Institute for Theoretical Physics), November 21st, 2024, during the VI Amazonian Symposium on Physics (https://www.ppgf.eventos.ufpa.br/VIASP).
Category: physics – Page 30
‘Next-Level’ Chaos Traces the True Limit of Predictability
“I give you God’s view,” said Toby Cubitt, a physicist turned computer scientist at University College London and part of the vanguard of the current charge into the unknowable, and “you still can’t predict what it’s going to do.”
Eva Miranda, a mathematician at the Polytechnic University of Catalonia (UPC) in Spain, calls undecidability a “next-level chaotic thing.”
Undecidability means that certain questions simply cannot be answered. It’s an unfamiliar message for physicists, but it’s one that mathematicians and computer scientists know well. More than a century ago, they rigorously established that there are mathematical questions that can never be answered, true statements that can never be proved. Now physicists are connecting those unknowable mathematical systems with an increasing number of physical ones and thereby beginning to map out the hard boundary of knowability in their field as well.
Crystal lattice at a distance: Moiré material method makes it easier to study interactions between electrons
To study the interactions between electrons in a material, physicists have come up with a number of tricks over the years. These interactions are interesting, among other things, because they lead to technologically important phenomena such as superconductivity.
In most materials, however, electron interactions are very weak and, therefore, hard to detect. One of the tricks that researchers have used for a while now consists in reducing the motional energy of the electrons by artificially creating a crystal lattice with a large lattice constant—that is, with a large distance between the lattice sites in the crystal. In this way, the interaction energy, which is still small, becomes relatively more important, so that interaction effects become visible.
However, the so-called moiré materials used for this suffer from the disadvantage that inside them it is not only the motion of electrons that is modified with respect to ordinary crystal lattices, but also other physical processes that are needed for studying the material.
The Holy Grail of Physics: Superconductivity Without the Cold
Researchers found that fundamental constants determine the upper limit of superconducting temperatures, and luckily, our Universe allows for conditions where this breakthrough might be possible.
The Holy Grail of Physics: Room-Temperature Superconductivity
A new study, published on March 3 in the Journal of Physics: Condensed Matter, suggests that room-temperature superconductivity — long considered the “holy grail” of condensed matter physics — may indeed be possible within the fundamental laws of the universe.
Astrophysicists predict origins of unexpected space objects in solar system and Alpha Centauri
Interstellar material has been discovered in our solar system, but researchers continue to hunt for where it came from and how it got here. A new study led by Western astrophysicists Cole Gregg and Paul Wiegert recommends Alpha Centauri—the next closest solar system to ours—is a great place to start, highlighting how and why it’s a prime target.
The findings were published March 6 in The Planetary Science Journal.
Interstellar objects are astronomical material, like asteroids or comets, not gravitationally bound to a star. They can come from other solar systems and be thrown into interstellar space by collisions or be slingshotted by a planet or star’s gravity.
Tunable asymmetric hysteresis loop: Researchers develop method to control magnetic reversal in Weyl semimetal
Recently, a research team found a new way to control the magnetic reversal in a special material called Co3Sn2S2, a Weyl semimetal. The team was led by Prof. Qu Zhe from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, in collaboration with Prof. Liu Enke from the Institute of Physics of the Chinese Academy of Sciences.
“This discovery could help switch the magnetization of devices that rely on magnetic properties,” said Prof. Qu, “such as hard drives and spin-based technologies.”
The results were published in Materials Today Physics.
What’s Your Brain’s Role in Creating Space & Time?
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Physics is the business of figuring out the structure of the world. So are our brains. But sometimes physics comes to conclusions that are in direct conflict with concepts fundamental to our minds, such as the realness of space and time. How do we tell who’s correct? Are time and space objective realities or human-invented concepts?
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Mass spectrometry method introduces novel concept for in-cell protein characterization
Proteins in cells are highly flexible and often exist in multiple conformations, each with unique abilities to bind ligands. These conformations are regulated by the organism to control protein function. Currently, most studies on protein structure and activity are conducted using purified proteins in vitro, which cannot fully replicate the complexity of the intracellular environment and may be influenced by the purification process or buffer conditions.
In a study published in the Journal of the American Chemical Society, a team led by Prof. Wang Fangjun from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences (CAS), collaborating with Prof. Huang Guangming from the University of Science and Technology of China of CAS, developed a new method for in-cell characterization of proteins using vacuum ultraviolet photodissociation top-down mass spectrometry (UVPD-TDMS), providing an innovative technology for analyzing the heterogeneity of intracellular protein in situ with MS.
Researchers combined in-cell MS with 193-nm UVPD to directly analyze protein structures within cells. This method employed induced electrospray ionization, which ionizes intracellular proteins with minimal structural perturbation.