Lifeboat Foundation

Scientists have devised a way of fabricating a complex structure, previously found only in nature, to open up new ways for manipulating and controlling light.

The structure, which naturally occurs in the wing scales of some species of butterfly, can function as a photonic crystal, according to a new study by researchers at the University of Birmingham. It can be used to control light in the visible range of the spectrum, for applications for lasers, sensors, and also devices for harvesting solar energy.

Their computational study, published in Advanced Materials, demonstrates that the complex gyroid structure can be self-assembled from designer colloidal particles in the range of hundreds of nanometers.

An experiment with an acoustic resonator demonstrates the quantum superposition of atoms—nearly matching the ability of matter interferometers to test quantumness on macroscopic scales.

Researchers at University of Oxford have recently created a quantum memory within a trapped-ion quantum network node. Their unique memory design, introduced in a paper in Physical Review Letters, has been found to be extremely robust, meaning that it could store information for long periods of time despite ongoing network activity.

“We are building a network of quantum computers, which use trapped ions to store and process quantum information,” Peter Drmota, one of the researchers who carried out the study, told Phys.org. “To connect quantum processing devices, we use single photons emitted from a single atomic ion and utilize quantum entanglement between this ion and the photons.”

Trapped ions, charged atomic particles that are confined in space using electromagnetic fields, are a commonly used platform for realizing quantum computations. Photons (i.e., the particles of light), on the other hand, are generally used to transmit quantum information between distant nodes. Drmota and his colleagues have been exploring the possibility of combining trapped ions with photons, to create more powerful quantum technologies.

The story of modern physics has been one of reductionism. We do not need a vast encyclopedia to understand the inner workings of Nature. Rather, we can describe a near-limitless range of natural phenomena, from the interior of a proton to the creation of galaxies, with apparently unreasonable efficiency using the language of mathematics. In the words of theoretical physicist Eugene Wigner, ‘The miracle of the appropriateness of the language of mathematics for the formulation of the laws of physics is a wonderful gift which we neither understand nor deserve. We should be grateful for it.’

The mathematics of the twentieth century described a Universe populated by a limited number of different types of fundamental particles interacting with each other in an arena known as spacetime according to a collection of rules that can be written down on the back of an envelope. If the Universe was designed, it seemed, the designer was a mathematician.

Today, the study of black holes appears to be edging us in a new direction, towards a language more often used by quantum computer scientists. The language of information. Space and time may be emergent entities that do not exist in the deepest description of Nature. Instead, they are synthesized out of entangled quantum bits of information in a way that resembles a cleverly constructed computer code. If the Universe is designed, it seems, the designer is a programmer.

Manipulating anything in the world of quantum physics is tricky, but now, scientists have managed to manipulate quantum light particles that have a strong relationship with each other. The breakthrough sounds a bit obscure, especially if you aren’t studying quantum mechanics yourself, but it’s a huge success that will be fundamental in how scientists study the quantum realm from here forward.

The Weibel instability is investigated using relativistic intense short laser pulses. A relativistic short laser pulse can generate a sub-relativistic high-density collisionless plasma. By irradiating double parallel planar targets with two relativistic laser pulses, sub-relativistic collisionless counterstreaming plasmas are created. Since the growth rate of the Weibel instability is proportional to the plasma density and velocity, the spatial and temporal scales of the Weibel instability can be much smaller than that from nanosecond large laser facilities. Recent theoretical and numerical studies have revealed that astrophysical collisionless shocks in sub-relativistic regimes in the absence and presence of an ambient magnetic field play essential roles in cosmic ray acceleration. With experimental verification in mind, we discuss the possible experimental models on the Weibel instability with intense short laser pulses. In order to show the experimental feasibility, we perform 2D particle-in-cell simulations in the absence of an external magnetic field as the first step and discuss the optimum conditions to realize the nonlinear evolutions of the Weibel instability in laboratories.

Although neutrinos are produced abundantly in collisions at the Large Hadron Collider (LHC), until now no neutrinos produced in such a way had been detected. Within just nine months of the start of LHC Run 3 and the beginning of its measurement campaign, the FASER collaboration changed this picture by announcing its first observation of collider neutrinos at this year’s electroweak session of the Rencontres de Moriond. In particular, FASER observed muon neutrinos and candidate events of electron neutrinos. “Our statistical significance is roughly 16 sigma, far exceeding 5 sigma, the threshold for a discovery in particle physics,” explains FASER’s co-spokesperson Jamie Boyd.

In addition to its observation of neutrinos at a particle collider, FASER presented results on searches for dark photons. With a null result, the collaboration was able to set limits on previously unexplored parameter space and began to exclude regions motivated by dark matter. FASER aims to collect up to ten times more data over the coming years, allowing more searches and neutrino measurements.

FASER is one of two new experiments situated at either side of the ATLAS cavern to detect neutrinos produced in proton collisions in ATLAS. The complementary experiment, [email protected], also reported its first results at Moriond, showing eight muon neutrino candidate events. “We are still working on the assessment of the systematic uncertainties to the background. As a very preliminary result, our observation can be claimed at the level of 5 sigma,” adds [email protected] spokesperson Giovanni De Lellis. The [email protected] detector was installed in the LHC tunnel just in time for the start of LHC Run 3.

Researchers have succeeded in creating an efficient quantum-mechanical light-matter interface using a microscopic cavity. Within this cavity, a single photon is emitted and absorbed up to 10 times by an artificial atom. This opens up new prospects for quantum technology, report physicists at the University of Basel and Ruhr-University Bochum in the journal Nature.

Quantum physics describes photons as light particles. Achieving an interaction between a single photon and a single atom is a huge challenge due to the tiny size of the atom. However, sending the photon past the atom several times by means of mirrors significantly increases the probability of an interaction.

In order to generate photons, the researchers use artificial atoms, known as quantum dots. These semiconductor structures consist of an accumulation of tens of thousands of atoms, but behave much like a single atom: when they are optically excited, their energy state changes and they emit a photon. “However, they have the technological advantage that they can be embedded in a semiconductor chip,” says Dr. Daniel Najer, who conducted the experiment at the Department of Physics at the University of Basel.

Researchers use an optical vortex beam to create a stable pattern of electron spins in a thin layer of semiconductor material.

Spin-based electronic, or “spintronic,” devices can benefit from techniques that coax electron spins into static spatial patterns called spin textures. A new experiment demonstrates that an optical vortex—a light beam that carries orbital angular momentum—can generate a stable spin texture in a semiconductor [1]. The research team showed that the vortex generates a pattern of stripes that has potential uses in processing spin information. Previous experiments have optically stimulated these striped textures, but the optical vortex has a structure that approximately overlaps with the stripe pattern, allowing faster spin-texture formation.

The spins of unbound electrons in a material can be aligned by a magnetic field or by polarized light. But as these electrons move—either through diffusion or through conduction—their spins will begin to rotate in response to so-called spin-orbit interactions within the material. The direction and rate of these rotations for any given electron depend on the path that it takes. Thus, two nearby electrons that start out aligned will become misaligned as they move along different paths, even if they arrive at the same destination. So maintaining an electronic spin texture seems like a doomed enterprise.