Phys.org September 30, 2021 To achieve a practical quantum network, we need to overcome several challenges including realizing versatile topologies for large scales, simple network maintenance, extendable configuration, and robustness to node failures. To this end, an international team of researchers (China, Germany) developed a field operation of a quantum metropolitan-area network with 46 nodes and showed that all these challenges can be overcome with cutting-edge quantum technologies. They used different topological structures and continuously ran the network for 31 months, by employing standard equipment for network maintenance with an extendable configuration. QKD pairing and key management was done with […]
Tag Archives: Communications technology
Tapping into magnets to clamp down on noise in quantum information
Phys.org September 3, 2021 Building on their earlier efforts to create a superconducting circuit integrated with magnetic elements, a team of researchers in the US (Argonne National Laboratory, University of Illinois) is investigating whether magnons could partner with microwave photons to ensure that microwaves can only travel in one direction, thereby essentially eliminating noise. They will be testing known and new material systems to find candidates that can handle an ultracold environment and operate in a real quantum device. According to the researchers if they are successful, it is possible to have magnetic structures directly integrated with quantum circuitry. The […]
Engineers bend light to enhance wavelength conversion
Nanowerk July 30, 2021 Incoming light can hit the electrons in the semiconductor lattice and move them to a higher energy state creating an electric field which further accelerates the high-energy electrons. They unload the extra energy by radiating it at different optical wavelengths, thus converting the wavelengths. An international team of researchers (USA – UCLA, Iowa State University, Germany) devised a solution for improving wavelength conversion using the semiconductor surface state phenomenon. They incorporated a nanoantenna array that bends incoming light, so it is confined around the shallow surface of the semiconductor converting the wavelength easily and without any […]
World’s first commercial re-programmable satellite blasts into space
Phys.org July 30, 2021 The European Space Agency launched the world’s first commercial fully re-programmable satellite from French Guiana on Friday [July 30, 2021] ushering in a new era of more flexible communications paving the way for a new era of more flexible communications. Unlike conventional models that are designed and “hard-wired” on Earth and cannot be repurposed once in orbit, the Eutelsat Quantum allows users to tailor the communications to their needs—almost in real-time. Because it can be reprogrammed while orbiting in a fixed position 35,000 kilometres (22,000 miles) above the Earth, the Quantum can respond to changing demands […]
New quantum research gives insights into how quantum light can be mastered
Phys.org July 22, 2021 Researchers at Los Alamos National Laboratory propose that modulated quantum metasurfaces can control all properties of photonic qubits, a breakthrough that could impact the fields of quantum information, communications, sensing and imaging, as well as energy and momentum harvesting. They developed a metasurface that looked like an array of rotated crosses, then proposed to shoot a single photon through the metasurface, where the photon splits into a superposition of many colors, paths, and spinning states generating quantum entanglement meaning the single photon can inherit different properties at once. According to the researchers by manipulating these properties, […]
Quantum holds the key to secure conference calls
EurekAlert June 6, 2021 Traditional quantum communication protocols consume pair-wise entanglement, which is suboptimal for distributed tasks involving more than two users. An international team of researchers (UK, Germany) has demonstrated quantum conference key agreement leveraging multipartite entanglement to efficiently create identical keys between N users with up to N-1 rate advantage in constrained networks. They distributed four-photon Greenberger-Horne-Zeilinger (GHZ) states, generated by high-brightness telecom photon-pair sources over optical fiber with combined lengths of up to 50 km and performed multiuser error correction and privacy amplification. Under finite-key analysis, they established 1.5 × 106 bits of secure key, which were […]
Exploiting non-line-of-sight paths for terahertz signals in wireless communications
EurekAlert April 27, 2021 A team of researchers in the US (Rice University, Brown University) investigated the idea of harnessing these specular NLOS (Non-Line-Of-Sight) paths for communication in directional networks at frequencies above 100 GHz. They explored several illustrative transmitter architectures, such as conventional substrate-lens dipole antenna and a leaky-wave antenna, to learn how these high-gain directional antennas offer both new challenges and new opportunities for exploiting NLOS paths. The results demonstrated the sensitivity to antenna alignment, power spectrum variations, and the disparity in supported bandwidth of various line-of-sight (LOS) and reflected path configurations. They showed that NLOS paths can, […]
New laser to help clear the sky of space debris
Phys.org April 12, 2021 The laser beams used for tracking space junk use infrared light and are not visible. The new guide star laser, which is mounted on a telescope, developed by an international team of researchers (from Australia, Japan, USA) propagates a visible orange beam into the night sky to create an artificial star that can be used to accurately measure light distortion between Earth and space. This guiding orange light enables adaptive optics to sharpen images of space debris. It can also guide a second, more powerful infra-red laser beam through the atmosphere to precisely track space debris or […]
Researchers establish the first entanglement-based quantum network
Phys.org April 15, 2021 Researchers in the Netherlands have built a three-node entanglement-based quantum network by combining remote quantum nodes based on diamond communication qubits into a scalable phase-stabilized architecture, supplemented with a robust memory qubit and local quantum logic. They achieved real-time communication and feed-forward gate operations across the network. They demonstrated two quantum network protocols without postselection: the distribution of genuine multipartite entangled states across the three nodes, and entanglement swapping through an intermediary node. The work establishes a key platform for exploring, testing, and developing multinode quantum network protocols and a quantum network control stack…read more. TECHNICAL […]
Detecting photons transporting qubits without destroying quantum information
Phys.org March 25, 2021 Photons that carry qubits over long distances are easily deflected from their path in the air or absorbed in glass fibers—and suddenly, the quantum information is lost. An international team of researchers (Germany, Spain) has developed a physical protocol that can indicate whether the qubit is lost at intermediate stations of the quantum transmission. If this is the case, the transmitter can send the qubit again with significantly less delay than if the loss is noticed only at the receiving end. The protocol only detects the qubit photon and not measure it. They achieved a nondestructive […]