State-Independent Geometric Quantum Gates via Nonadiabatic and Noncyclic Evolution

Geometric phases are robust to local noises and the nonadiabatic ones can reduce the evolution time, thus nonadiabatic geometric gates have strong robustness and can approach high fidelity. However, the advantage of geometric phase has not been fully explored in previous investigations. Here,a scheme is proposed for universal quantum gates with pure nonadiabatic and noncyclic geometric phases from smooth evolution paths. In the scheme, only geometric phase can be accumulated in a fast way, and thus it not only fully utilizes the local noise resistant property of geometric phase but also reduces the difficulty in experimental realization. Numerical results show that the implemented geometric gates have stronger robustness than dynamical gates and the geometric scheme with cyclic path. Furthermore, it proposes to construct universal quantum gate on superconducting circuits, with the fidelities of single-qubit gate and nontrivial two-qubit gate can achieve 99.97% and 99.87%, respectively. Therefore, these high-fidelity quantum gates are promising for large-scale fault-tolerant quantum computation.     

Deterministic separation of arbitrary photon pair states in integrated quantum circuits

Entangled photon pairs must often be spatially separated for their subsequent manipulation in integrated quantum circuits. Separation that is both deterministic and universal can in principle be achieved through anti‐coalescent two‐photon quantum interference. However, such interference‐facilitated pair separation (IFPS) has not been extensively studied in the integrated setting, which has important implications on performance. This work provides a detailed review of IFPS and examines how integrated device dependencies such as dispersion impact separation fidelity and interference visibility. The analysis applies equally to both on‐chip and in‐fiber implementations. When coupler dispersion is present, the separation performance can depend on photon bandwidth, spectral entanglement and the dispersion. By design, reduction in the separation fidelity due to loss of non‐classical interference can be perfectly compensated for by classical wavelength demultiplexing effects. This work informs the design of devices for universal photon pair separation of states with tunable arbitrary properties.

     

Commutativity of first‐order discrete‐time linear time‐varying systems

After introducing the concept of commutativity for continuous‐time linear time‐varying systems, the related literature and the results obtained so far are presented. For a simple introduction of the commutativity of discrete‐time linear time‐varying systems, the problem is formulated for first‐order systems. Finally, explicit necessary and sufficient conditions for the commutativity of first‐order discrete‐time linear time‐varying systems are derived, and their advantageous use in digital system design is illustrated, which are the main objectives of the paper. The results are verified by examples which include an application in amplitude modulation for digital telecommunication.     

Proposing an efficient algorithm for designing universal nanoelectronic molecular logic gates

In today's world, there are still demands for minimising the dimensions of electronic circuits, the result of which is designing nanoelectronic circuits and very small molecular gates and switches. The point which causes trouble in this design is high impact of different parameters on the performance of circuit. Despite the suggestion of simple electronic circuits and different gates, impact of parameters like length of molecule, angle between different atoms, coupling situation of electrodes to molecule, the type of atoms used in a molecule's structure and other cases has made their development almost impossible. In this paper, there was an attempt to study previous works in order to, first, mention the effects of different conditions on circuit performance and, second, present an algorithm for designing gates so as to minimise the effects of these parameters on circuit performance.     

最佳通用逻辑门ULG.2 的应用研究

本文在作者以前研究的基础上,进一步研究最佳通用逻辑门ULG.2的应用,提出了用ULG.2组成的一些脉冲电路。     

Impedance modelling of two-phase solid-state ionic conductors. Part II—application to high-lithium-content <Emphasis Type="Italic">x</Emphasis>Li<Subscript>2</Subscript>O–B<Subscript>2</Subscript>O<Subscript>3</Subscript> fast-ion conducting glasses

The equivalent circuit model of two-phase ionic conductors, introduced in Part I of this work, was applied to a set of xLi₂O–B₂O₃ fast-ion conducting glasses, with x ranging from 3.0 to 4.5. The shape of Arrhenius plots, constructed by equivalent circuit fitting of impedance spectra measured at various temperatures, turned out to be in agreement with the predictions of the model. The analysis procedure, which was developed by mathematical investigation in accordance with the implications of the model, was employed to determine the activation energies of the two present phases and the total DC ionic resistivity of the examined glasses.     

An Approach for Microprobe Measurement and Modeling for Millimeter-Wave Application

This paper describes a simple method to check the performance of microprobe. The two-port S-parameters of the microprobe are determined by one-port S-parameters measurement using HP 8510XF Network Analyzer. Based on the measurement, an equivalent circuit model for the microprobe is presented and good agreement between the measurement results and modeling results is obtained.     

The two independent equations of circuits in integral form of field theory:The fundamental law of circuits

1 Introduction Historically, circuit theory was initially considered as a part of the electromagnetic theory. Later on, it branched out to become an independent theory. After several stages of its development, Kirchhoff’s law was commonly regarded as the fundamental law of circuits[1]. Especially after the 1960s, the completely topological formulation of Kirchhoff’s law made even more important contribution to the development of moderncircuit theory. However, it has been also known for a l…     

A Chaotic Circuit with Ferroelectric Nonlinearity

In this paper, the possibility of observing strange attractors in an electronic circuit including a nonlinear ferroelectric component has been investigated. The ferroelectric constitutes the medium interposed between the two plates of a capacitor. A circuit including the nonlinearity of the ferroelectric has been designed, while the parameters have been found by performing numerical integration with respect to different values of them. The circuit has been realized on a discrete components board. Experimental results, showing that for a suitable range of parameters a chaotic attractor emerges, are reported.     

UHF机械调谐器调谐电容片形的程序设计

采用传输线理论可以计算机械式UHF调谐器对应不同频率点的调谐电容量。在进行满足直线频率关系的调谐电容片形设计时,应当求出调谐电容量C_Τ与旋转角θ的显式函数关系。但对于分布参数的电路,这有一定的困难。本文采用数值计算方法完成了具有良好直线频率跟踪特性的调谐电容片形的设计,并由计算机自动绘出了片形。