Phys.org November 29, 2024 Strongly driven nonlinear optical processes such as spontaneous parametric down-conversion and spontaneous four-wave mixing can produce multiphoton nonclassical beams of light which have applications in quantum information processing and sensing. In contrast to the low-gain regime, new physical effects arise in a high-gain regime due to the interactions between the nonclassical light and the strong pump driving the nonlinear process. Researchers in Canada described and experimentally observed a gain-induced group delay between the multiphoton pulses generated in a high-gain type-II spontaneous parametric down-conversion source. The researchers concluded that since the group delay introduced distinguishability between the […]
Tag Archives: Information processing
New partially coherent unidirectional imaging system enhances visual data transmission
Phys.org October 28, 2024 Unidirectional imagers form images of input objects only in one direction. Researchers at UCLA reported unidirectional imaging under spatially partially coherent light and demonstrated high-quality imaging only in the forward direction (A → B) with high power efficiency while distorting the image formation in the backward direction (B → A) along with low power efficiency. Their analyses revealed that when illuminated by a partially coherent beam with a correlation length of ≥∼1.5λ, where λ was the wavelength of light, diffractive unidirectional imagers achieved robust performance, exhibiting asymmetric imaging performance between the forward and backward directions. A […]
On the way to optical logic gates: Study demonstrates the basics for purely optical processing of information
Phys.org September 2, 2024 An international team of researchers (Germany, Australia) created arrays of polymer beads (photonic units) incorporating photo-switchable DAE molecules using surface-templated electrophoretic deposition. They could be reversibly and individually switched between high and low emission states by direct photoexcitation, without any energy or electron transfer processes within the molecular system. The micropatterned array of these photonic units was spectroscopically characterized in detail and optimized with respect to both signal contrast and crosstalk. The optimum optical parameters were determined. 500 cycles were demonstrated with no obvious on/off contrast attenuation. They demonstrated the possibility of continuous recording. According to […]
Theoretical research holds promise for advancing modular quantum information processing
Phys.org August 15, 2024 As quantum information processing systems are scaled to many qubits to reach their full potential, highly complex electronics are needed to control the complex circuitry. A team of researchers in the US (University of Rhode Island, University of Maryland, NIST, UCLA) considered a pair of quantum dot-based spin qubits that interact via microwave photons in a superconducting cavity and parametrically driven by separate external electric fields. For this system, they formulated a model for spin qubit entanglement in the presence of mutually off-resonant qubit and cavity frequencies. They showed that the sidebands generated via the driving […]
The transformation between different topological spin textures
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 […]
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 […]