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Category: particle physics – Page 322

“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.

Since that time, the MOSFET has become the most widely manufactured device in history. Thanks to vast improvements in miniaturisation, the latest processors now contain 114 billion transistors, making them 50 million times more powerful than the Intel 4004.

Continue reading “Transistor gate is just 0.3 nm long” | >

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.

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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.

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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 .

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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.

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A team of researchers working at Tsinghua University in China has created a sub-1-nm gate in a MoS2 transistor. In their paper published in the journal Nature, the group outlines how they created the super tiny gate and explains why they believe it will be difficult for anyone to beat their record.

For most of the history of microcomputing, Moore’s Law has held up—researchers and engineers have managed to double the speed and capability of computers regularly by reducing the size of their components. But more recently, it has grown increasingly difficult to make components smaller as scientists now run into . In this new effort, the researchers believe they may have bumped up against the ultimate limit—they have built a gate that is just one atom in length.

At their most basic, transistors are a source and a drain, with a gate controlling the flow of electricity between them. It switches on and off depending on how much electricity is applied. The push to reduce the size of the components has led to the testing of materials such as carbon nanotubes, which are approximately 1nm, for use as gates. In this new effort, the researchers have unrolled the and used its graphene edge as the gate—reducing its length to just 0.34 nm.

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Probability of a reaction occurring increases 100-fold and points to quantum control of chemistry.

A new step towards quantum control of chemistry has been achieved by researchers in the US, who found that tuning the magnetic field applied to colliding ultracold molecules could alter the probability of them reacting or undergoing inelastic scattering a 100-fold.1 The work could potentially prove useful for producing large ensembles of molecules in the same state and investigating their properties.

At room temperature, the random thermal motion of atoms and molecules blurs the quantum nature of chemistry. In an ultracold regime, however, this thermal motion is stilled, revealing chemical interactions as quantum interference processes between matter waves. Remarkable phenomena have been seen in ultracold atomic gases, such as the creation of Bose–Einstein condensates, in which atoms all enter the quantum ground state of a trap, allowing a macroscopic view of their quantum wavefunction. Wolfgang Ketterle at the Massachusetts Institute of Technology (MIT), whose group performed the new research, shared the 2001 physics Nobel prize for the creation of this condensate.

Cooling molecules to the ground state of a trap is much trickier than cooling atoms because they can contain thermal energy in so many internal degrees of freedom, and was only achieved by Jun Ye of JILA in the US and colleagues recently.2 In 2020, Ye’s group applied an electric field to potassium–rubidium molecules, which decay into diatomic potassium and rubidium molecules. The researchers showed that, at a specific field, the molecules were excited into states forbidden by quantum mechanics and could get close enough to react. This drastically slowed the decay rate. ‘For our system, we typically think that, if the two molecules get very close together, there is close to a 100% chance that they will undergo a chemical reaction,’ explains Kyle Matsuda, Ye’s PhD student and the 2020 paper’s lead author.

Continue reading “Magnetic fields can have a huge impact on reactivity of ultracold molecules” | >