Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: particle physics – Page 90

Diamonds are famously formed under high pressure and temperature, which is partly why they’re so valuable. But now, scientists have created diamonds in a lab under regular pressure in just 15 minutes.

Diamonds are basically just plain old carbon that’s been put under immense pressure and temperature, causing the atoms to crystallize into a particular structure. On Earth, the only place with the right natural conditions is deep in the mantle, hundreds of miles down. Only later are they brought closer to the surface, hitching rides in volcanic eruptions, which makes them pretty rare. Couple that with some of the most insidious marketing in history, and you’ve got a highly sought-after little rock.

Scientists have been growing diamonds in labs for decades, but it usually still needs those extreme conditions – almost 50,000 atmospheres of pressure, and temperatures of about 1,500 °C (2,732 °F). But a new technique has now produced diamonds under normal pressure levels and cooler temperatures.

Read more | >

Similar to optical vortex beams, terahertz (THz) vortex beams (TVBs) also carry orbital angular momentum (OAM). However, little research has been reported on the generation of TVBs. In this paper, based on the detour phase technique, we design a series of spintronic terahertz emitters with a helical Fresnel zone plate (STE-HFZP) to directly generate focused TVBs with topological charges (TCs) of l = ±1, ±2 and ±3, respectively. The STE-HFZP is a hybrid THz device composed of a terahertz emitter and a THz lens, and it has a high numerical aperture (NA), achieving subwavelength focal spots. Its focus properties are surveyed systemically through accurate simulations. This STE-HFZP can also generate focused TVBs with higher order TCs.

Read more | >

Researchers at the University of Hong Kong discovered Dirac spinons in the material YCu3-Br, providing evidence of a quantum spin liquid state and potentially advancing applications in quantum computing and high-temperature superconductivity.

Quasiparticles are fascinating entities that arise from collective behavior within materials and can be treated as a group of particles. Specifically, Dirac spinons are anticipated to exhibit unique characteristics similar to Dirac particles in high-energy physics and Dirac electrons in graphene and quantum moiré materials, such as a linear dispersion relation between energy and momentum. However, spin-½ charge-neutral quasiparticles had not been observed in quantum magnets until this work.

‘“To find Dirac spinons in quantum magnets has been the dream of generations of condensed matter physicists; now that we have seen the evidence of them, one can start to think about the countless potential applications of such highly entangled quantum material. Who knows, maybe one-day people will build quantum computers with it, just as people have been doing in the past half-century with silicon,’” said Professor Meng, HKU physicist and one of the corresponding authors of the paper.

Read more | >

Many of today’s quantum devices rely on collections of qubits, also called spins. These quantum bits have only two energy levels, the ‘0’ and the ‘1’. However, unlike classical bits, qubits can exist in superpositions, meaning they can simultaneously be in a combination of the ‘0’ and ‘1’ states. Spins in real devices also interact with light and vibrations known as bosons, greatly complicating calculations.

In a new publication in Physical Review Letters (“Fast quantum state preparation and bath dynamics using non-Gaussian variational Ansatz and quantum optimal control”), researchers in Amsterdam demonstrate a way to describe spin-boson systems and use this to efficiently configure quantum devices in a desired state.

Quantum devices use the quirky behaviour of quantum particles to perform tasks that go beyond what ‘classical’ machines can do, including quantum computing, simulation, quantum sensing, quantum communication and quantum metrology. These devices can take many forms, such as a collection of superconducting circuits, or a lattice of atoms or ions held in place by lasers or electric fields.

Read more | >

New solar observations indicate that plasma waves are responsible for the Sun’s outer atmosphere having different abundances of chemical elements than the Sun’s other layers.

The solar corona is a halo of hot, tenuous plasma that surrounds the Sun out to large distances. It is visible during solar eclipses (Fig. 1) but is usually outshone by the glare of the Sun’s surface, or photosphere. The corona has different abundances of chemical elements than the rest of the Sun, and a longstanding question has been why this disparity exists. New solar measurements by Mariarita Murabito at the Italian National Institute of Astrophysics (INAF) and colleagues suggest that the difference is caused by plasma waves dragging easily ionized elements from the Sun’s lower atmosphere into the corona [1]. This finding could lead to a better understanding of the structure of stars.

The corona is of great interest to solar physicists, partly because it produces the solar wind—an outflow of hot gas from the Sun. The solar wind is most evident to us on Earth when its particles become trapped in Earth’s magnetic field and collide with our atmosphere, causing an aurora. An important problem in solar physics is to determine which coronal structures generate the solar wind and how solar conditions affect the outflow’s properties. The elemental composition of the solar wind sheds light on its origins, as this composition does not change once the gas leaves the Sun. The solar wind can be directly sampled by spacecraft in situ, and its elemental abundances can be compared to coronal abundances inferred from spectroscopy.

Read more | >

In a new publication in Physical Review Letters, researchers in Amsterdam demonstrate a way to describe spin-boson systems and use this to efficiently configure in a desired state.

Quantum devices use the quirky behavior of quantum particles to perform tasks that go beyond what “classical” machines can do, including quantum computing, simulation, sensing, communication and metrology. These devices can take many forms, such as a collection of superconducting circuits, or a lattice of atoms or ions held in place by lasers or electric fields.

Regardless of their physical realization, quantum devices are typically described in simplified terms as a collection of interacting two-level or spins. However, these spins also interact with other things in their surroundings, such as light in superconducting circuits or oscillations in the lattice of atoms or ions. Particles of light (photons) and vibrational modes of a lattice (phonons) are examples of bosons.

Read more | >

Researchers have developed techniques to manufacture different types of glass in space, uncovering potential for advancements in optical technology.

Thanks to human ingenuity and zero gravity, we reap important benefits from science in space. Consider smartphones with built-in navigation systems and cameras.

Such transformational technologies seem to blend into the rhythm of our everyday lives overnight. But they emerged from years of discoveries and developments of materials that can withstand harsh environments outside our atmosphere. They evolved from decades of laying foundations in basic science to understand how atoms behave in different materials under different conditions.

Read more | >

The universe is expanding at an accelerating rate but Einstein’s theory of General Relativity and our knowledge of particle physics predict that this shouldn’t be happening. Most cosmologists pin their hopes on Dark Energy to solve the problem. But, as Claudia de Rham argues, Einstein’s theory of gravity is incorrect over cosmic scales, her new theory of Massive Gravity limits gravity’s force in this regime, explains why acceleration is happening, and eliminates the need for Dark Energy.

You can see Claudia de Rham live, debating in ‘Dark Energy and The Universe’ alongside Priya Natarajan and Chris Lintott and ‘Faster Than Light’ with Tim Maudlin and João Magueijo at the upcoming HowTheLightGetsIn Festival on May 24th-27th in Hay-on-Wye.

This article is presented in association with Closer To Truth, an esteemed partner for the 2024 HowTheLightGetsIn Festival.

Read more | >

The delicate nature of quantum information means it does not travel well. A quantum Internet therefore needs devices known as quantum repeaters to swap entanglement between quantum bits, or qubits, at intermediate points. Several researchers have taken steps towards this goal by distributing entanglement between multiple nodes.

In 2020, for example, Xiao-Hui Bao and colleagues in Jian-Wei Pan’s group at the University of Science and Technology of China (USTC) entangled two ensembles of rubidium-87 atoms in vapour cells using photons that had passed down 50 km of commercial optical fibre. Creating a functional quantum repeater is more complex, however: “A lot of these works that talk about distribution over 50,100 or 200 kilometres are just talking about sending out entangled photons, not about interfacing with a fully quantum network at the other side,” explains Can Knaut, a PhD student at Harvard University and a member of the US team.

Read more | >