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Category: quantum physics – Page 111

A new nanometer-scale measurement tool exploits the quantum properties of light for better precision and speed

University of Illinois Physics Professor Paul Kwiat and members of his research group have developed a new tool for precision measurement at the nanometer scale in scenarios where background noise and optical loss from the sample are present.

This new optical interferometry technology leverages the quantum properties of light—specifically, extreme color entanglement—to enable faster and more precise measurements than widely used classical and quantum techniques can achieve.

Colin Lualdi, Illinois Physics graduate student and lead author of the study, emphasizes, “By taking advantage of both quantum interference and , we can make measurements that would otherwise be difficult with existing methods.”

Researchers unveil 3D magnon control, charting a new course for neuromorphic and quantum technologies

What if the magnon Hall effect, which processes information using magnons (spin waves) capable of current-free information transfer with magnets, could overcome its current limitation of being possible only on a 2D plane? If magnons could be utilized in 3D space, they would enable flexible design, including 3D circuits, and be applicable in various fields such as next-generation neuromorphic (brain-mimicking) computing structures, similar to human brain information processing.

KAIST and an international joint research team have, for the first time, predicted a 3D magnon Hall effect, demonstrating that magnons can move freely and complexly in 3D space, transcending the conventional concept of magnons. The work is published in the journal Physical Review Letters.

Professor Se Kwon Kim of the Department of Physics, in collaboration with Dr. Ricardo Zarzuela of the University of Mainz, Germany, has revealed that the interaction between magnons (spin waves) and solitons (spin vortices) within complex (topologically textured frustrated magnets) is not simple, but complex in a way that enables novel functionalities.

Study shows domain walls in ferroelectrics can be the most stable state, enabling high-density memory

A research team, led by Professor Junhee Lee from the Graduate School of Semiconductor Materials and Devices Engineering at UNIST, has demonstrated through quantum mechanical calculations that charged domain walls in ferroelectrics—once thought to be unstable—can, in fact, be more stable than the bulk regions.

This discovery opens new avenues for developing high-density semiconductor memory devices capable of storing information as binary states (0s and 1s) based on the presence or absence of .

This research was conducted in collaboration with researchers Pawan Kumar and Dipti Gupta, who served as the first author and co-author, respectively. The research is published in the journal Physical Review Letters.

Photon manipulation near absolute zero: New record for processing individual light particles

Scientists at Paderborn University have made a further step forward in the field of quantum research: for the first time ever, they have demonstrated a cryogenic circuit (i.e. one that operates in extremely cold conditions) that allows light quanta—also known as photons—to be controlled more quickly than ever before.

Specifically, these scientists have discovered a way of using circuits to actively manipulate made up of individual photons. This milestone could substantially contribute to developing modern technologies in quantum information science, communication and simulation. The results have now been published in the journal Optica.

Photons, the smallest units of light, are vital for processing quantum information. This often requires measuring a ’s state in real time and using this information to actively control the luminous flux—a method known as a “feedforward operation.”

Quantum computing and photonics discovery potentially shrinks critical parts by 1,000 times

Researchers have made a discovery that could make quantum computing more compact, potentially shrinking essential components 1,000 times while also requiring less equipment. The research is published in Nature Photonics.

A class of quantum computers being developed now relies on light particles, or photons, created in pairs linked or “entangled” in quantum physics parlance. One way to produce these photons is to shine a laser on millimeter-thick crystals and use optical equipment to ensure the photons become linked. A drawback to this approach is that it is too big to integrate into a computer chip.

Now, Nanyang Technological University, Singapore (NTU Singapore) scientists have found a way to address this approach’s problem by producing linked pairs of photons using much thinner materials that are just 1.2 micrometers thick, or about 80 times thinner than a strand of hair. And they did so without needing additional optical gear to maintain the link between the , making the overall set-up simpler.

Using a fermionic neural network to find the ground state of fractional quantum Hall liquids

When two-dimensional electron systems are subjected to magnetic fields at low temperatures, they can exhibit interesting states of matter, such as fractional quantum Hall liquids. These are exotic states of matter characterized by fractionalized excitations and the emergence of interesting topological phenomena.

Researchers at Cavendish Laboratory and Massachusetts Institute of Technology (MIT) set out to better understand these fascinating states using machine learning, specifically employing a newly developed attention-based fermionic (FNN).

The method they developed, outlined in a paper published in Physical Review Letters, was trained to find the lowest-energy quantum state (i.e., ground state) of fractional quantum Hall liquids.

Laser Cooling is Optimized for Efficiency

A new laser-based cooling scheme approaches the maximum efficiency that is theoretically achievable.

Much of the progress in 20th-century physics has centered around understanding the interaction between light and matter. The availability of well-controlled light sources—lasers—enabled experimental exploration of controlled light–matter interactions and, specifically, methods to cool atoms close to absolute zero temperatures [1, 2]. Several laser-cooling methods, such as Doppler cooling and resolved sideband cooling, are used routinely to prepare controlled quantum states of atoms. Brennen de Neeve of the Swiss Federal Institute of Technology (ETH) Zurich and his colleagues now show just how efficient a laser-cooling process can be [3] (Fig. 1). They demonstrate a laser-cooling method that uses a “spin-dependent force” to transfer motional entropy from the atom into the entropy of its internal degrees of freedom.

‘Intercrystals’ pave the way for greener electronics and quantum technologies

Rutgers University–New Brunswick researchers have discovered a new class of materials—called intercrystals—with unique electronic properties that could power future technologies.

Intercrystals exhibit newly discovered forms of electronic properties that could pave the way for advancements in more efficient electronic components, and environmentally friendly materials, the scientists said.

As described in a report in the science journal Nature Materials, the scientists stacked two ultrathin layers of graphene, each a one-atom-thick sheet of carbon atoms arranged in a hexagonal grid. They twisted them slightly atop a layer of hexagonal boron nitride, a hexagonal crystal made of boron and nitrogen. A subtle misalignment between the layers that formed moiré patterns—patterns similar to those seen when two fine mesh screens are overlaid—significantly altered how electrons moved through the material, they found.

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