Quantum devices and computers will need operational units in different architectural configurations for their functioning. The unit should be a simple "quantum toy," an easy to handle superposition state. Here such a novel unit of quantum mechanical flux state (or persistent current) in a conducting ring with three ferromagnetic quantum dots is presented. The state is labeled by the two directions of the persistent current, which is driven by the spin chirality of the dots, and is controlled by the spin (the spin Josephson effect). It is demonstrated that by the use of two connected rings, one can carry out unitary transformations on the input flux state by controlling one spin in one of the rings, enabling us to prepare superposition states. The flux is shown to be a quantum operation gate, and may be useful in quantum computing.
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http://dx.doi.org/10.1103/PhysRevLett.91.076806 | DOI Listing |
Sci Rep
December 2024
Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1205, Bangladesh.
Prediction and discovery of new materials with desired properties are at the forefront of quantum science and technology research. A major bottleneck in this field is the computational resources and time complexity related to finding new materials from ab initio calculations. In this work, an effective and robust deep learning-based model is proposed by incorporating persistent homology with graph neural network which offers an accuracy of and an F1 score of in classifying topological versus non-topological materials, outperforming the other state-of-the-art classifier models.
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December 2024
Institute of Physics, Chinese Academy of Sciences, Beijing, China.
Spin-polarized edge states in two-dimensional materials hold promise for spintronics and quantum computing applications. Constructing stable edge states by tailoring two-dimensional semiconductor materials with bulk-boundary correspondence is a feasible approach. Recently layered NiI is suggested as a two-dimensional type-II multiferroic semiconductor with intrinsic spiral spin ordering and chirality-induced electric polarization.
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December 2024
Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, USA.
Non-Hermitian models describe the physics of ubiquitous open systems with gain and loss. One intriguing aspect of non-Hermitian models is their inherent topology that can produce intriguing boundary phenomena like resilient higher-order topological insulators (HOTIs) and non-Hermitian skin effects (NHSE). Recently, time-multiplexed lattices in synthetic dimensions have emerged as a versatile platform for the investigation of these effects free of geometric restrictions.
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December 2024
School of Materials Science and Engineering, Peking University, Beijing, 100871, China.
Crystal symmetry, which governs the local atomic coordination and bonding environment, is one of the paramount constituents that intrinsically dictate materials' functionalities. However, engineering crystal symmetry is not straightforward due to the isotropically strong covalent/ionic bonds in crystals. Layered two-dimensional materials offer an ideal platform for crystal engineering because of the ease of interlayer symmetry operations.
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December 2024
School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
Quantum computers now encounter the significant challenge of scalability, similar to the issue that classical computing faced previously. Recent results in high-fidelity spin qubits manufactured with a Si CMOS technology, along with demonstrations that cryogenic CMOS-based control/readout electronics can be integrated into the same chip or die, opens up an opportunity to break out the challenges of qubit size, I/O, and integrability. However, the power consumption of cryogenic CMOS-based control/readout electronics cannot support thousands or millions of qubits.
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