Scientists used a technique called ‘active syndrome extraction’ to build four logical qubits from 30 physical ones and run 14,000 experiments without detecting a single error.
Category: quantum physics – Page 327
Researchers visualize quantum effects in electron waves
One of the most fundamental interactions in physics is that of electrons and light. In an experiment at Goethe University Frankfurt, scientists have now managed to observe what is known as the Kapitza-Dirac effect for the first time in full temporal resolution. This effect was first postulated more than 90 years ago, but only now are its finest details coming to light.
Reimagining quantum dot single-photon sources: A breakthrough in monolithic Fabry-Perot microcavities
Self-assembled semiconductor quantum dots (QDs) represent a three-dimensional confined nanostructure with discrete energy levels, which are similar to atoms. They are capable of producing highly efficient and indistinguishable single photons on demand and are important for exploring fundamental quantum physics and various applications in quantum information technologies. Leveraging traditional semiconductor processes, this material system also offers a natural integration-compatible and scalable platform.
Study unveils a new family of quantum anomalous Hall insulators
Researchers at Fudan University in China have recently been trying to identify new promising quantum anomalous Hall insulators. Their latest paper, published in Physical Review Letters, outlines the unique characteristics of monolayer V2MX4, which could belong to a new family of quantum anomalous Hall insulators.
“Finding intrinsic quantum anomalous Hall materials is an important goal in topological material research,” Jing Wang, co-author of the paper, told Phys.org. “After we predicted MnBi2Te4, a paradigm example of magnetic topological insulator and exhibiting quantum anomalous Hall effect in odd layer, we have been thinking about finding new intrinsic quantum anomalous Hall insulator with large gap.”
Large-gap quantum anomalous Hall insulator materials exhibit a quantum anomalous Hall effect with a relatively large energy gap between the valence and conduction band. These materials should exhibit a synergy between two seemingly conflicting properties, namely spin-orbit coupling and ferromagnetism.
Classical optical neural network exhibits ‘quantum speedup’
In recent years, artificial intelligence technologies, especially machine learning algorithms, have made great strides. These technologies have enabled unprecedented efficiency in tasks such as image recognition, natural language generation and processing, and object detection, but such outstanding functionality requires substantial computational power as a foundation.
Quantum Leap: Redefining Complex Problem-Solving
The traveling salesman problem is considered a prime example of a combinatorial optimization problem. Now a Berlin team led by theoretical physicist Prof. Dr. Jens Eisert of Freie Universität Berlin and HZB has shown that a certain class of such problems can actually be solved better and much faster with quantum computers than with conventional methods.
Quantum computers use so-called qubits, which are not either zero or one as in conventional logic circuits, but can take on any value in between. These qubits are realized by highly cooled atoms, ions, or superconducting circuits, and it is still physically very complex to build a quantum computer with many qubits. However, mathematical methods can already be used to explore what fault-tolerant quantum computers could achieve in the future.
“There are a lot of myths about it, and sometimes a certain amount of hot air and hype. But we have approached the issue rigorously, using mathematical methods, and delivered solid results on the subject. Above all, we have clarified in what sense there can be any advantages at all,” says Prof. Dr. Jens Eisert, who heads a joint research group at Freie Universität Berlin and Helmholtz-Zentrum Berlin.