Exact Numerical Solution of the BCS Pairing Problem

We propose a new simulation computational method to solve the reduced BCS Hamiltonian based on spin analogy and submatrix diagonalization. Then we further apply this method to solve superconducting energy gap and the results are well consistent with those obtained by Bogoliubov transformation method. The exponential problem of 2^{N}-dimension matrix is reduced to the polynomial problem of N-dimension matrix. It is essential to validate this method on a real quantumComment: 7 pages, 3 figure

Nuclear charge radii in Bayesian neural networks revisited

In this work, a refined Bayesian neural network (BNN) based approach with six inputs including the proton number, mass number, and engineered features associated with the pairing effect, shell effect, isospin effect, and ``abnormal" shape staggering effect of $^{181,183,185}$Hg, is proposed to accurately describe nuclear charge radii. The new approach is able to well describe the charge radii of atomic nuclei with $A\ge40$ and $Z\ge20$. The standard root-mean-square (rms) deviation is $0.014$ fm for both the training and validation data. In particular, the predicted charge radii of proton-rich and neutron-rich calcium isotopes are found in good agreement with data. We further demonstrate the reliability of the BNN approach by investigating the variations of the rms deviation with extrapolation distances, mass numbers, and isospin asymmetries.Comment: 16 pages, 6 figure

Design and Study of Cognitive Network Physical Layer Simulation Platform

Cognitive radio technology has received wide attention for its ability to sense and use idle frequency. IEEE 802.22 WRAN, the first to follow the standard in cognitive radio technology, is featured by spectrum sensing and wireless data transmission. As far as wireless transmission is concerned, the availability and implementation of a mature and robust physical layer algorithm are essential to high performance. For the physical layer of WRAN using OFDMA technology, this paper proposes a synchronization algorithm and at the same time provides a public platform for the improvement and verification of that new algorithm. The simulation results show that the performance of the platform is highly close to the theoretical value

2-(2-Bromo­eth­yl)isoindoline-1,3-dione

The asymmetric unit of the title compound, C10H8BrNO2, contains three crystallographically independent mol­ecules. Two of the N—C—C—Br side chains adopt anti conformations [torsion angles = −179.8 (5) and −179.4 (4)°] and the other is gauche [−66.5 (6)°]. The crystal structure features short Br⋯O [3.162 (5) Å] contacts, C—H⋯O hydrogen bonds and numerous π–π stacking inter­actions [centroid–centroid separations = 3.517 (4)–3.950 (4) Å]