Twisting singular solutions of Bethe's equations

The Bethe equations for the periodic XXX and XXZ spin chains admit singular solutions, for which the corresponding eigenvalues and eigenvectors are ill-defined. We use a twist regularization to derive conditions for such singular solutions to be physical, in which case they correspond to genuine eigenvalues and eigenvectors of the Hamiltonian.Comment: 10 pages; v2: references added; v3: introduction expanded, and more references adde

Boundary energy of the open XXX chain with a non-diagonal boundary term

We analyze the ground state of the open spin-1/2 isotropic quantum spin chain with a non-diagonal boundary term using a recently proposed Bethe ansatz solution. As the coefficient of the non-diagonal boundary term tends to zero, the Bethe roots split evenly into two sets: those that remain finite, and those that become infinite. We argue that the former satisfy conventional Bethe equations, while the latter satisfy a generalization of the Richardson-Gaudin equations. We derive an expression for the leading correction to the boundary energy in terms of the boundary parameters.Comment: 10 pages, 9 figures; v2: Figs 4 are improved; v3: reference added; v4: erratum adde

Algebraic Bethe ansatz for singular solutions

The Bethe equations for the isotropic periodic spin-1/2 Heisenberg chain with N sites have solutions containing i/2, -i/2 that are singular: both the corresponding energy and the algebraic Bethe ansatz vector are divergent. Such solutions must be carefully regularized. We consider a regularization involving a parameter that can be determined using a generalization of the Bethe equations. These generalized Bethe equations provide a practical way of determining which singular solutions correspond to eigenvectors of the model.Comment: 10 pages; v2: refs added; v3: new section on general singular solutions, and more reference

Residual Stress Nondestructive Testing Technology Using Nonlinear Ultrasonic

The nonlinear ultrasonic theory is that ultrasonic waves interact with micro defects and the higher harmonic waves appear when the ultrasonic waves propagate in materials. The acoustic nonlinear parameters are sensitive to micro defects in the nonlinear materials. They are used to characterize the nonlinear characteristics of materials. The nonlinear ultrasonic theories and the characterization of stress in metal by the nonlinear ultrasonic are studied. The nonlinear ultrasonic testing system is built to detect the received signals which propagate in materials with stress. The variation trends of the nonlinear parameters is studied in tensile testing. This paper studies the relationship between nonlinear parameter and stress in different coupling states including contact coupling, air coupling, water coupling. Use manipulator to measure residual stress based on nonlinear ultrasonic and achieve a rapid, non-contact and non-destructive testing

Influence on Vestibular Function by Auditory Neuropathy

AbstractObjectiveThe main purpose of the present study was to describe the vestibular function in patients with auditory neuropathy (AN), and to assess their ability to maintain balance.MethodsVestibular function tests were performed on 32 patients with AN and 36 normal subjects including electronystagmopraphy(ENG) and static postrography(SPG). The results from the two groups were compared.ResultsEquilibrium function in patients with AN, was abnormal, compared to normal subjects.ConclusionVestibular function tests, especially static postrography, should be performed on patients with AN

Education and Social Inequality in China Elite Groups Perpetuating Their Privileged Status

At a time of growing economic and social inequality in China, there is a tendency to invoke education as a great leveller but that rose-tinted view fails to take cognisance of the role of entrenched vested interests which are in fact nurturing educational disparities precisely because education helps to perpetuate them. Current arrangements in education in China can thus hardly help achieve or promote a harmonious society

Éducation et inégalités sociales en Chine

À une époque où les inégalités économiques et sociales se creusent en Chine, on est en droit d’espérer que l’éducation sera un moyen efficace de réduire les disparités. Cet optimisme se heurte toutefois au rôle des élites qui, en tentant de défendre leurs intérêts et de perpétuer leur supériorité, renforcent les inégalités dans le domaine de l’éducation. Aussi les dispositions en vigueur aujourd’hui ne sont-elles pas le meilleur moyen de bâtir la « société harmonieuse » souhaitée par le pouvoir

Design Space Exploration and Comparative Evaluation of Memory Technologies for Synaptic Crossbar Arrays: Device-Circuit Non-Idealities and System Accuracy

In-memory computing (IMC) utilizing synaptic crossbar arrays is promising for deep neural networks to attain high energy efficiency and integration density. Towards that end, various CMOS and post-CMOS technologies have been explored as promising synaptic device candidates which include SRAM, ReRAM, FeFET, SOT-MRAM, etc. However, each of these technologies has its own pros and cons, which need to be comparatively evaluated in the context of synaptic array designs. For a fair comparison, such an analysis must carefully optimize each technology, specifically for synaptic crossbar design accounting for device and circuit non-idealities in crossbar arrays such as variations, wire resistance, driver/sink resistance, etc. In this work, we perform a comprehensive design space exploration and comparative evaluation of different technologies at 7nm technology node for synaptic crossbar arrays, in the context of IMC robustness and system accuracy. Firstly, we integrate different technologies into a cross-layer simulation flow based on physics-based models of synaptic devices and interconnects. Secondly, we optimize both technology-agnostic design knobs such as input encoding and ON-resistance as well as technology-specific design parameters including ferroelectric thickness in FeFET and MgO thickness in SOT-MRAM. Our optimization methodology accounts for the implications of device- and circuit-level non-idealities on the system-level accuracy for each technology. Finally, based on the optimized designs, we obtain inference results for ResNet-20 on CIFAR-10 dataset and show that FeFET-based crossbar arrays achieve the highest accuracy due to their compactness, low leakage and high ON/OFF current ratio