Lifeboat Foundation

The researchers simulated the molecules H4, molecular nitrogen, and solid diamond. These involved as many as 120 orbitals, the patterns of electron density formed in atoms or molecules by one or more electrons. These are the largest chemistry simulations performed to date with the help of quantum computers.

A classical computer actually handles most of this fermionic quantum Monte Carlo simulation. The quantum computer steps in during the last, most computationally complex step—calculating the differences between the estimates of the ground state made by the quantum computer and the classical computer.

The prior record for chemical simulations with quantum computing employed 12 qubits and a kind of hybrid algorithm known as a variational quantum eigensolver (VQE). However, VQEs possess a number of limitations compared with this new hybrid approach. For example, when one wants a very precise answer from a VQE, even a small amount of noise in the quantum circuitry “can cause enough of an error in our estimate of the energy or other properties that’s too large,” says study coauthor William Huggins, a quantum physicist at Google Quantum AI in Mountain View, Calif.

The problem is that transitions from one s-orbital to another are forbidden, quantum mechanically. There’s no way to emit one photon from an s-orbital and have your electron wind up in a lower energy s-orbital, so the transition we talked about earlier, where you emit a Lyman-series photon, can only occur from the 2 p state to the 1s state.

But there is a special, rare process that can occur: a two-photon transition from the 2s state (or the 3s, or 4s, or even the 3 d orbital) down to the ground (1s) state. It occurs only about 0.000001% as frequently as the Lyman-series transitions, but each occurrence nets us one new neutral hydrogen atom. This quantum mechanical quirk is the primary method of creating neutral hydrogen atoms in the Universe.

If it weren’t for this rare transition, from higher energy spherical orbitals to lower energy spherical orbitals, our Universe would look incredibly different in detail. We would have different numbers and magnitudes of acoustic peaks in the cosmic microwave background, and hence a different set of seed fluctuations for our Universe to build its large-scale structure out of. The ionization history of our Universe would be different; it would take longer for the first stars to form; and the light from the leftover glow of the Big Bang would only take us back to 790,000 years after the Big Bang, rather than the 380,000 years we get today.

“Moore’s law could once again get a reprieve, in spite of the naysayers.”

Using graphene and molybdenum disulphide, scientists in China have made a transistor gate with a length of only 0.3 nanometres, equivalent to just one carbon atom, by exploiting the vertical aspect of the device.

In 1959, scientists at Bell Labs invented the metal–oxide–semiconductor field-effect transistor (MOSFET). This led to mass-production of transistors for a wide range of applications – including computer processors. The Intel 4,004, the first commercially produced microprocessor, debuted in 1971 and featured 2,250 transistors on a single chip, using a 10,000 nm (10 µm) fabrication process.

Continue reading “Transistor gate is just 0.3 nm long” »

Fabrication routes for high-performance pitch-based carbon fibers are identified through a comprehensive modeling framework.

Since the discovery of the Higgs boson a decade ago, the ATLAS and CMS collaborations at the Large Hadron Collider (LHC) have been hard at work trying to unlock the secrets of this special particle. In particular, they have been investigating in detail how the Higgs boson interacts with fundamental particles such as those that make up matter, that is, quarks and leptons. In the Standard Model of particle physics, these matter particles fall into three categories, or “generations”, of increasing mass, and the Higgs boson interacts with them with a strength that is proportional to their mass. Any deviation from this behaviour would provide a clear indication of new phenomena.

ATLAS and CMS have previously observed the interactions of the Higgs boson with the heaviest quarks and leptons, i.e. those of the third generation, which agree with the predictions from the Standard Model within the current measurement precision. They have also obtained the first indications that the Higgs boson interacts with a muon, a lepton of the second generation. However, they have yet to observe it interacting with second-generation quarks. In two recent publications, ATLAS and CMS report analyses that place tight limits on the strength of the Higgs boson’s interaction with a charm quark, a second-generation quark.

ATLAS and CMS study the Higgs boson’s interactions by looking at how it transforms, or “decays”, into lighter particles or how it is produced together with other particles. In their latest studies, using data from the second run of the LHC, the two teams searched for the decay of the Higgs boson into a charm quark and its antimatter counterpart, the charm antiquark.

Nature proves truth is still stranger than fiction: A pulsar has shot energetic particles in a thin, straight line that extends for light-years into space. The discovery might explain how antimatter makes its way to Earth.

Star Trek can keep its ray guns — pulsars make far more powerful beams of radiation.

Crushed stellar cores, left behind when a massive star goes supernova, are among nature’s own particle accelerators. Though pulsars are only the size of Manhattan, their dizzying spins and powerful magnetic fields can energize particles to a significant fraction of the speed of light. In addition, pulsars glow with high-energy radiation, which can itself convert into pairs of electrons and their antimatter counterpart, positrons.

Ever since its discovery in 2004, graphene has received attention owing to its extraordinary properties, among them its extremely high carrier mobility. However, the high carrier mobility has only been observed using techniques that require complex and expensive fabrication methods. Now, researchers at Chalmers report on a surprisingly high charge-carrier mobility of graphene using much cheaper and simpler methods.

“This finding shows that graphene transferred to cheap and flexible substrates can still have an uncompromisingly high mobility, and it paves the way for a new era of graphene nano-electronics,” says Munis Khan, researcher at Chalmers University of Technology.

Graphene is the one-atom-thick layer of carbon atoms, known as the world’s thinnest material. The material has become a popular choice in semiconductor, automotive and optoelectronic industry due to its excellent electrical, chemical, and material properties. One such property is its extremely high carrier mobility.

Dude, what if everything around us was just … a hologram?

The thing is, it could be—and a University of Michigan physicist is using quantum computing and machine learning to better understand the idea, called holographic duality.

Holographic duality is a mathematical conjecture that connects theories of particles and their interactions with the theory of gravity. This conjecture suggests that the theory of gravity and the theory of particles are mathematically equivalent: what happens mathematically in the theory of gravity happens in the theory of particles, and vice versa.

An experiment conducted on hybrid matter-antimatter atoms has defied researchers’ expectations.