Phys.org November 11, 2022 Skyrmions and bimerons are versatile topological spin textures that can be used as information bits for both classical and quantum computing. An international team of researchers (Japan, China, Australia) has demonstrated the creation of isolated skyrmions and their subsequent transformation to bimerons by harnessing the electric current-induced Oersted field and temperature-induced perpendicular magnetic anisotropy variation. The reversible transformation between skyrmions and bimerons was controlled by the current amplitude and scanning direction. Both skyrmions and bimerons could be created in the same system through the skyrmion-bimeron transformation and magnetization switching. Deformed skyrmion bubbles and chiral labyrinth domains […]
Tag Archives: Information processing
New optical switch could lead to ultrafast all-optical signal processing
Phys.org August 1, 2022 The weak native nonlinearity of most nanophotonic platforms has imposed barriers for the use of optical nonlinear functions for applications in integrated photonics, including all-optical information processing, photonic neural networks, and on-chip ultrafast light sources, by necessitating large driving energies, high-Q cavities, or integration with other materials with stronger nonlinearity. A team of researchers in the US (Caltech, Cornell University) has effectively utilized the strong and instantaneous quadratic nonlinearity of lithium niobate nanowaveguides for the realization of cavity-free all-optical switching. By simultaneous engineering of the dispersion and quasi-phase matching, they designed and demonstrated a nonlinear splitter […]
A well-known iron-based magnet is also a potential quantum information material
Phys.org January 13, 2022 For quantum information processing the strongest-performing permanent magnets contain expensive rare-earth metals magnets. Researchers at the Iowa State University scanned vast number of iron-based permanent magnets and established that lanthanum-based hexaferrites show an advantage over conventional samarium-based hexaferrites. They identified LaFe12O19 as an excellent candidate for a gap magnet (iron-based permanent magnet). It is an excellent wide-bandgap semiconductor, can withstand higher voltages, frequencies, and temperatures. They discovered a new quantum state in this material, which strongly locks the magnetization along a fixed direction in the crystal, it could host other rare earths possessing nontrivial localized electronic […]
Trapping spins with sound
Science Daily November 1, 2021 Lattice defects in crystals often come along with certain magnetic properties. To use them as promising systems for applications in quantum technologies an international team of researchers (Germany, Russia) has developed an efficient method to control their spin states using surface acoustic waves (SAW). They demonstrated a giant interaction between the strain field of SAW and the excited-state spin of silicon vacancies in silicon carbide, which is about two orders of magnitude stronger than in the ground state. The simultaneous spin driving in the ground and excited states with the same SAW leads to the […]
New approach to information transfer reaches quantum speed limit
Phys.org August 5, 2021 A team of researchers in the US (University of Maryland, University of Colorado) designed a quantum protocol that reaches the theoretical speed limits for certain quantum tasks. In the new protocol, data stored on one qubit is shared with its neighbors using entanglement. The qubits work together to spread it to other sets of qubits. Because more qubits are involved, they transfer the information even more quickly. This process can be repeated to generate larger blocks of qubits that pass the information faster and faster. They found that the snowballing qubits speed along the information at […]
The next generation of information processing is through coherent gate operations
Phys.org July 14, 2021 Electromagnonics—the hybridization of spin excitations and electromagnetic waves—has been recognized as a promising candidate for coherent information processing in recent years. Among its various implementations, the lack of available approaches for real-time manipulation on the system dynamics has become a common and urgent limitation. A team of researchers in the US (Argonne National Laboratory, University of Chicago) introduced a fast and uniform modulation technique and demonstrated a series of benchmark coherent gate operations in hybrid magnonics, including semiclassical analogies of Landau-Zener transitions, Rabi oscillations, Ramsey interference, and controlled mode swap operations. Their approach lays the groundwork […]
A new piece of the quantum computing puzzle
Phys.og June 29, 2021 The challenge in optical quantum information processing has been the realization of two-qubit gates for photonic qubits due to the lack of highly efficient optical Kerr nonlinearities at the single-photon level. A team of researchers in the US (Washington University, University of Michigan) found that a high-fidelity frequency-encoded deterministic two-photon controlled-phase gate can be achieved by exploiting the strong photon-photon correlation enabled by photonic dimers, and the unique nonreciprocal photonic propagation in chiral quantum nanophotonic systems. They are testing the design to show that it can operate under moderate conditions. According to the researchers so far […]
Controlling magnetization by surface acoustic waves
Nanowerk May 27, 2021 Interconversion between electron spin and other forms of angular momentum is useful for spin-based information processing. Well-studied examples of this are the conversion of photon angular momentum and rotation into ferromagnetic moment. Recently, several theoretical studies have suggested that the circular vibration of atoms work as phonon angular momentum; however, conversion between phonon angular momentum and spin-moment has yet to be demonstrated. Researchers in Japan demonstrated that the phonon angular momentum of surface acoustic wave can control the magnetization of a ferromagnetic Ni film by means of the phononic-to-electronic conversion of angular momentum in a Ni/LiNbO3 […]
Developing smarter, faster machine intelligence with light
Phys.org December 18, 2020 Optical alternatives to electronic hardware could help speed up machine learning processes by simplifying the way information is processed in a non-iterative way. However, photonic-based machine learning is typically limited by the number of components that can be placed on photonic integrated circuits, limiting the interconnectivity, while free-space spatial-light-modulators are restricted to slow programming speeds. A team of researchers in the US (George Washington University, UCLA, industry) replaced spatial light modulators with digital mirror-based technology, thus developing a system over 100 times faster. The non-iterative timing of this processor, in combination with rapid programmability and massive […]
Physics breakthrough of the year
EurekAlert December 17, 2020 Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon, germanium and SiGe alloys are all indirect-bandgap semiconductors that cannot emit light efficiently. An international team of researchers (Canada, the Netherlands, Germany, Austria) has demonstrated efficient light emission from direct-bandgap hexagonal Ge and SiGe alloys. They measured a sub-nanosecond, temperature-insensitive radiative recombination lifetime and observed an emission yield similar to that of direct-bandgap group-III–V semiconductors. They demonstrated that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously […]