Robust interface between flying and topological qubits

Hybrid architectures, consisting of conventional and topological qubits, have recently attracted much attention due to their capability in consolidating the robustness of topological qubits and the universality of conventional qubits. However, these two kinds of qubits are normally constructed in significantly different energy scales, and thus this energy mismatch is a major obstacle for their coupling that supports the exchange of quantum information between them. Here, we propose a microwave photonic quantum bus for a direct strong coupling between the topological and conventional qubits, in which the energy mismatch is compensated by the external driving field via the fractional ac Josephson effect. In the framework of tight-binding simulation and perturbation theory, we show that the energy splitting of the topological qubits in a finite length nanowire is still robust against local perturbations, which is ensured not only by topology, but also by the particle-hole symmetry. Therefore, the present scheme realizes a robust interface between the flying and topological qubits. Finally, we demonstrate that this quantum bus can also be used to generate multipartitie entangled states with the topological qubits.Comment: Accepted for publication in Scientific Report

Optimized Design on the Width and Spacing of the Cross Passageway in Tunnels

AbstractCross passageways have been commonly applied in the evacuation system of tunnels, and the width and spacing of the cross passageways decide the evacuation capacity of the tunnel. In design, increasing the width of the cross passageways and reducing their spacing can improve the evacuation ability of tunnels. However, it will certainly increase the cost of the project. Under the precondition of meeting evacuation requirements, an optimization model was established in this article, which aimed at reducing the cost of the project. Finally, discussions on the application of this optimization model were carried on, and this method may provide reference for designing cross passageways

Implementing universal nonadiabatic holonomic quantum gates with transmons

Geometric phases are well known to be noise-resilient in quantum evolutions/operations. Holonomic quantum gates provide us with a robust way towards universal quantum computation, as these quantum gates are actually induced by nonabelian geometric phases. Here we propose and elaborate how to efficiently implement universal nonadiabatic holonomic quantum gates on simpler superconducting circuits, with a single transmon serving as a qubit. In our proposal, an arbitrary single-qubit holonomic gate can be realized in a single-loop scenario, by varying the amplitudes and phase difference of two microwave fields resonantly coupled to a transmon, while nontrivial two-qubit holonomic gates may be generated with a transmission-line resonator being simultaneously coupled to the two target transmons in an effective resonant way. Moreover, our scenario may readily be scaled up to a two-dimensional lattice configuration, which is able to support large scalable quantum computation, paving the way for practically implementing universal nonadiabatic holonomic quantum computation with superconducting circuits.Comment: v3 Appendix added, v4 published version, v5 published version with correction

Text Mining-Based Patent Analysis for Automated Rule Checking in AEC

Automated rule checking (ARC), which is expected to promote the efficiency of the compliance checking process in the architecture, engineering, and construction (AEC) industry, is gaining increasing attention. Throwing light on the ARC application hotspots and forecasting its trends are useful to the related research and drive innovations. Therefore, this study takes the patents from the database of the Derwent Innovations Index database (DII) and China national knowledge infrastructure (CNKI) as data sources and then carried out a three-step analysis including (1) quantitative characteristics (i.e., annual distribution analysis) of patents, (2) identification of ARC topics using a latent Dirichlet allocation (LDA) and, (3) SNA-based co-occurrence analysis of ARC topics. The results show that the research hotspots and trends of Chinese and English patents are different. The contributions of this study have three aspects: (1) an approach to a comprehensive analysis of patents by integrating multiple text mining methods (i.e., SNA and LDA) is introduced ; (2) the application hotspots and development trends of ARC are reviewed based on patent analysis; and (3) a signpost for technological development and innovation of ARC is provided

Microwave electrometry with multi-photon coherence in Rydberg atoms

A scheme for measurement of microwave (MW) electric field is proposed via multi-photon coherence in Rydberg atoms. It is based on the three-photon electromagnetically induced absorption (TPEIA) spectrum. In this process, the multi-photon produces a narrow absorption peak, which has a larger magnitude than the electromagnetically induced transparency (EIT) peak under the same conditions. The TPEIA peak is sensitive to MW fields, and can be used to measure MW electric field strength. It is interesting to find that the magnitude of TPEIA peaks shows a linear relationship with the MW field strength. The simulation results show that the minimum detectable strength of the MW fields is about 1/10 that based on an common EIT effect, and the probe sensitivity is improved by about 4 times. Furthermore, the MW sensing based on three-photon coherence shows a broad tunability, and the scheme may be useful for designing novel MW sensing devices.Comment: 6 pages,13 figure

Distinguishing and Forgery Attacks on Alred and Its AES-based Instance Alpha-MAC

In this paper, we present new distinguishers of the MAC construction \textsc{Alred} and its specific instance \textsc{Alpha}-MAC based on AES, which is proposed by Daemen and Rijmen in 2005. For the \textsc{Alred} construction, we describe a general distinguishing attack which leads to a forgery attack directly. The complexity is $2^{64.5}$ chosen messages and $2^{64.5}$ queries with success probability 0.63. We also use a two-round collision differential path for \textsc{Alpha}-MAC, to construct a new distinguisher with about $2^{65.5}$ queries. The most important is that the new distinguisher can be used to recover the internal state, which is an equivalent secret subkey, and leads to a second preimage attack. Moreover, the distinguisher on \textsc{Alred} construction is also applicable to the MACs based on CBC and CFB encryption mode