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Category: particle physics – Page 132

Quantum entanglement: A simple way to fully grasp this ‘impossible’ concept

Measurement in quantum mechanics presents unique challenges. Observing one particle in an entangled pair determines the states of both, leading to critical inquiries: What constitutes a ‘measurement,’ and how does it influence our understanding of reality?

The complex mathematics underpinning quantum mechanics — incorporating concepts like Hilbert spaces, wave functions, and operators — can be intimidating, rendering entanglement less accessible to many.

Simply put, quantum entanglement is just too complicated for most people to fully understand. It defies classical intuitions, involves sophisticated mathematics, and urges us to reevaluate our understanding of reality.

Team develops method for control over single-molecule photoswitching

The new research centers on the use of LSPs to achieve atomic-level control of chemical reactions. A team has successfully extended LSP functionality to semiconductor platforms. By using a plasmon-resonant tip in a low-temperature scanning tunneling microscope, they enabled the reversible lift-up and drop-down of single organic molecules on a silicon surface.

The LSP at the tip induces breaking and forming specific chemical bonds between the molecule and silicon, resulting in the reversible switching. The switching rate can be tuned by the tip position with exceptional precision down to 0.01 nanometer. This precise manipulation allows for reversible changes between two different molecular configurations.

An additional key aspect of this breakthrough is the tunability of the optoelectronic function through molecular modification. The team confirmed that photoswitching is inhibited for another organic molecule, in which only one oxygen atom not bonding to silicon is substituted for a nitrogen atom. This chemical tailoring is essential for tuning the properties of single-molecule optoelectronic devices, enabling the design of components with specific functionalities and paving the way for more efficient and adaptable nano-optoelectronic systems.

Engineers make tunable, shape-changing metamaterial inspired by vintage toys

Common push puppet toys in the shapes of animals and popular figures can move or collapse with the push of a button at the bottom of the toys’ base. Now, a team of UCLA engineers has created a new class of tunable dynamic material that mimics the inner workings of push puppets, with applications for soft robotics, reconfigurable architectures and space engineering.

Inside a push puppet, there are connecting cords that—when pulled taut—will make the toy stand stiff. But by loosening these cords, the “limbs” of the toy will go limp. Using the same cord tension-based principle that controls a puppet, researchers have developed a new type of metamaterial, a material engineered to possess properties with promising advanced capabilities.

Published in Materials Horizons, the study demonstrates the new lightweight metamaterial, which is outfitted with either motor-driven or self-actuating cords that are threaded through interlocking cone-tipped beads. When activated, the cords are pulled tight, causing the nesting chain of bead particles to jam and straighten into a line, making the material turn stiff while maintaining its overall structure.

Quantum sensor detects magnetic and electric fields from a single atom

The next step, says Esat, is to increase the new device’s magnetic field sensitivity by implementing more advanced sensing protocols based on pulsed electron spin resonance schemes and by finding molecules with longer spin decoherence times. “We hope to increase the sensitivity by a factor of about 1,000, which would allow us to detect nuclear spins at the atomic scale,” he says.

A holy grail for quantum sensing

The new atomic-scale quantum magnetic field sensor should also make it possible to resolve spins in certain emerging two-dimensional quantum materials. These materials are predicted to have many complex magnetic orders, but they cannot be measured with existing instruments, Heinrich and his QNS colleague Yujeong Bae note. Another possibility would be to use the sensor to study so-called encapsulated spin systems such as endohedral-fullerenes, which comprise a magnetic core surrounded by an inert carbon cage.

World’s first micromachine twists 2D materials at will

Just a few years ago, researchers discovered that changing the angle between two layers of graphene, an atom-thick sheet of carbon, also changed the material’s electronic and optical properties. They then learned that a “twist” of 1.1 degrees—dubbed the “magic” angle—could transform this metallic material into an insulator or a superconductor, a finding that ignited excitement about a possible pathway to new quantum technologies.

Deviations in particle interactions point to the existence of new bosons

The Standard Model of particle physics is the mathematical description of the fundamental constituents and interactions of matter. While it is the accepted theory encapsulating our current state-of-the-art knowledge in particle physics, it is incomplete as it is unable to describe many glaring phenomena in nature.

Crivellin and Mellado’s article describes deviations in the decay of multi-lepton particles in the LHC, compared to how they should behave according to the Standard Model. These deviations, or anomalies, constitute excesses in the production of particles called electrons and its heavy cousin, the muon, on top of the predictions from the Standard Model.

“An is something that stands out as unusual or different from what is normal or expected. In this case, this is a deviation from the Standard Model of Particle physics. Anomalies can be important because they often signal that something unexpected or significant has happened,” says Crivellin.