Lifeboat Foundation

A team of researchers from MIT and several institutions in Korea has found that the speed of magnetic domain wall movement is fundamentally limited. In their paper published in the journal Science, the group describes testing a theory regarding the maximum speed of domain walls to prove them correct. Matthew Daniels and Mark Stiles with the National Institute of Standards and Technology in the U.S. have published a Perspective piece outlining the work by the researchers in the same journal issue and sum up the implications of their findings.

One of the basic tenets of Einstein’s theory of special relativity is that there is no particle that can travel faster than the speed of light. In this new effort, the researchers have found a similar boundary for magnetic domain walls.

Materials that are magnetic have domains in which ordered spins are separated from one another by boundaries known as domain walls. Prior research has shown that such walls can be moved by applying an electric current. This particular aspect of magnetic materials has formed the basis of research on racetrack memory. And because the speed of movement of the domain walls determines the speed of the memories created using them, scientists have been pushing them faster and faster. Logic suggests that there must be a limit to how fast the domain walls can be pushed, however, thus establishing a limit to how fast such memories can operate. In this new effort, the researchers have found that fundamental limit.

How do molecular catalysts—molecules which, like enzymes, can trigger or accelerate certain chemical reactions—function, and what effects do they have? A team of chemists at the University of Oldenburg has come closer to the answers using a model molecule that functions like a molecular nanobattery. It consists of several titanium centers linked to each other by a single layer of interconnected carbon and nitrogen atoms. The seven-member research team recently published its findings, which combine the results of three multi-year Ph.D. research projects, in ChemPhysChem. The physical chemistry and chemical physics journal featured the basic research from Oldenburg on its cover.

To gain a better understanding of how the molecule works, the researchers, headed by first authors Dr. Aleksandra Markovic and Luca Gerhards and corresponding author Prof. Dr. Gunther Wittstock, performed electrochemical and spectroscopic experiments and used the university’s high-performance computing cluster for their calculations. Wittstock sees the publication of the paper as a “success story” for both the Research Training Groups within which the Ph.D. projects were conducted and for the university’s computing cluster. “Without the high-performance computing infrastructure, we would not have been able to perform the extensive calculations required to decipher the behavior of the molecule,” says Wittstock. “This underlines the importance of such computing clusters for current research.”

In the paper, the authors present the results of their analysis of a molecular structure, the prototype for which was the result of an unexpected chemical reaction first reported by the University of Oldenburg’s Chemistry Department in 2006. It is a highly complex molecular structure in which three titanium centers (commonly referred to in high school lessons as titanium ions) are connected to each other by a bridging ligand consisting of carbon and nitrogen. Such a compound would be expected to be able to accept and release several electrons through the exchange of electrons between the metal centers among other reasons.

The crystalline solid BaTiS₃ (barium titanium sulfide) is terrible at conducting heat, and it turns out that a wayward titanium atom that exists in two places at the same time is to blame.

The discovery, made by researchers from Caltech, USC, and the Department of Energy’s Oak Ridge National Laboratory (ORNL), was published on November 27 in the journal Nature Communications. It provides a fundamental atomic-level insight into an unusual thermal property that has been observed in several materials. The work is of particular interest to researchers who are exploring the potential use of crystalline solids with poor thermal conductivity in thermoelectric applications, in which heat is directly converted into electric energy and vice versa.

“We have found that quantum mechanical effects can play a huge role in setting the thermal transport properties of materials even under familiar conditions like room temperature,” says Austin Minnich, professor of mechanical engineering and applied physics at Caltech and co-corresponding author of the Nature Communications paper.

The new atomic clock design, which uses entangled atoms, could help scientists detect dark matter and study gravity’s effect on time.

Atomic clocks are the most precise timekeepers in the world. These exquisite instruments use lasers to measure the vibrations of atoms, which oscillate at a constant frequency, like many microscopic pendulums swinging in sync. The best atomic clocks in the world keep time with such precision that, if they had been running since the beginning of the universe, they would only be off by about half a second today.

Still, they could be even more precise. If atomic clocks could more accurately measure atomic vibrations, they would be sensitive enough to detect phenomena such as dark matter and gravitational waves. With better atomic clocks, scientists could also start to answer some mind-bending questions, such as what effect gravity might have on the passage of time and whether time itself changes as the universe ages.

Graphene, one of the most important nanomaterials developed so far, continues to surprise the scientific community. This time, thanks to the extraordinary phenomena found by a group of physicists from the University of Arkansas. We are talking specifically about the capacity to use the thermal motion of atoms in graphene as a source of energy!

In this recent work, published in Physical Review E under the title Fluctuation-induced current from freestanding graphene, the team of researchers have successfully developed a circuit capable of capturing graphene’s thermal motion and converting it into an electrical current.

As it is said in this article : “The idea of harvesting energy from graphene is controversial because it refutes physicist Richard Feynman’s well-known assertion that the thermal motion of atoms, known as Brownian motion, cannot do work. Thibado’s team found that at room temperature the thermal motion of graphene does in fact induce an alternating current (AC) in a circuit, an achievement thought to be impossible.”

For decades, scientists have merely guessed it exists. They finally found proof it does.

Quantum computational advantage or supremacy is a long-anticipated milestone toward practical quantum computers. Recent work claimed to have reached this point, but subsequent work managed to speed up the classical simulation and pointed toward a sample size–dependent loophole. Quantum computational advantage, rather than being a one-shot experimental proof, will be the result of a long-term competition between quantum devices and classical simulation. Zhong et al. sent 50 indistinguishable single-mode squeezed states into a 100-mode ultralow-loss interferometer and sampled the output using 100 high-efficiency single-photon detectors. By obtaining up to 76-photon coincidence, yielding a state space dimension of about 10³⁰, they measured a sampling rate that is about 10¹⁴-fold faster than using state-of-the-art classical simulation strategies and supercomputers.

Science, this issue p. 1460

Quantum computers promise to perform certain tasks that are believed to be intractable to classical computers. Boson sampling is such a task and is considered a strong candidate to demonstrate the quantum computational advantage. We performed Gaussian boson sampling by sending 50 indistinguishable single-mode squeezed states into a 100-mode ultralow-loss interferometer with full connectivity and random matrix—the whole optical setup is phase-locked—and sampling the output using 100 high-efficiency single-photon detectors. The obtained samples were validated against plausible hypotheses exploiting thermal states, distinguishable photons, and uniform distribution. The photonic quantum computer, Jiuzhang, generates up to 76 output photon clicks, which yields an output state-space dimension of 10³⁰ and a sampling rate that is faster than using the state-of-the-art simulation strategy and supercomputers by a factor of ~10¹⁴.

When it comes to magnetic tape storage capacity, smaller is larger. That is, as the magnetic particles that store data become smaller, more data can be stockpiled in the same amount of space.

Two leading tech giants put that simple principle to work and announced Wednesday that they have developed a magnetic tape cartridge boasting the most dense storage capacity of any media in the world. Fujifilm and IBM say research into a new material, strontium ferrite, led to the creation of a tape cartridge capable of storing 580 terabytes of data. That’s enough to store roughly 580 million books, according to an IBM blog post published Wednesday.

Considering there are about only 130 million books in existence today, that’ll leave plenty of room for extras.

Jack Steinberger, who shared the 1988 Nobel Prize in Physics for expanding understanding of the ghostly neutrino, a staggeringly ubiquitous subatomic particle, died on Saturday at his home in Geneva. He was 99.

His wife, Cynthia Alff, confirmed the death.

The ancient Greeks proposed that there was one invisible, indivisible unit of matter: the atom. But modern physics has found more than 100 smaller entities lurking within atoms, and observations of their dizzying interactions compose the Standard Model of what is now taken to be the order of the universe.