Consistency check of charged hadron multiplicities and fragmentation functions in SIDIS

We derived the conditions on certain combinations of integrals of the fragmentation functions of pion using HERMES data of the sum for the charged pion multiplicities from semi-inclusive deep-inelastic scattering (SIDIS) off the deuteron target. In our derivation the nucleon parton distribution functions (PDFs) are assumed to be isospin SU(2) symmetric. Similar conditions have also been obtained for the fragmentation functions (FFs) of kaon by the sum of charged kaon multiplicities as well. We have chosen several FFs to study the impact of those conditions we have derived. Among those FFs, only that produced in the nonlocal chiral-quark model (NL$\chi$QM) constantly satisfy the conditions. Furthermore, the ratios of the strange PDFs $S(x)$ and the nonstrange PDFs $Q(x,Q^2)$ extracted from the charged pion and kaon multiplicities differ from each other significantly. Finally, we demonstrate that the HERMES pion multiplicity data is unlikely to be compatible with the two widely-used PDFs, namely CTEQ6M and NNPDF3.0.Comment: 11 pages, 5 fig

Border is better than distance? Contagious corruption in one belt one road economies

Employing data of one belt one road (OBOR) countries from 2002 to 2013, this study compares the contagious corruption difference between geographic border and distance through the dynamic spatial econometric model. The empirical results not only confirm that corruption in OBOR countries exists under various contagious channels, but also indicate that border effects, serving as contagious channels for corruption, are better than distance effects. The empirical implication is that OBOR countries with a common border tend to possess contagious corruption due to the hosts’ demonstration effect and the convenience of transferring illegal assets. We advise that those OBOR countries should enhance the supervision of cash flow, look for any opportunity of kicking back a portion of the stolen money, and establish a specific task force on corruption

On compression rate of quantum autoencoders: Control design, numerical and experimental realization

Quantum autoencoders which aim at compressing quantum information in a low-dimensional latent space lie in the heart of automatic data compression in the field of quantum information. In this paper, we establish an upper bound of the compression rate for a given quantum autoencoder and present a learning control approach for training the autoencoder to achieve the maximal compression rate. The upper bound of the compression rate is theoretically proven using eigen-decomposition and matrix differentiation, which is determined by the eigenvalues of the density matrix representation of the input states. Numerical results on 2-qubit and 3-qubit systems are presented to demonstrate how to train the quantum autoencoder to achieve the theoretically maximal compression, and the training performance using different machine learning algorithms is compared. Experimental results of a quantum autoencoder using quantum optical systems are illustrated for compressing two 2-qubit states into two 1-qubit states

Electric-dipole matrix-element formulas in hyperspherical coordinates with applications to H\u3csup\u3e-\u3c/sup\u3e and He

Theoretical formulas for the length, velocity, and acceleration forms of the electric-dipole matrix element within the adiabatic hyperspherical coordinate representation are presented. The length and acceleration formulas are used to calculate the photoionization cross section for He up to 1.0 a.u. above threshold and the photodetachment cross section for H- up to 0.35 a.u. above threshold. Length- and acceleration-form results for the dipole oscillator strengths for the discrete He transitions, 1sns(1Se)→1smp(1P0), where n=1, 2, and 3 and m=2, 3, and 4, are also presented. The accuracy of the length- and acceleration-form adiabatic hyperspherical coordinate approximation results is discussed

Strongly-coupled nanotube electromechanical resonators

Coupling an electromechanical resonator with carbon-nanotube quantum dots is a significant method to control both the electronic charge and the spin quantum states. By exploiting a novel micro-transfer technique, we fabricate two strongly-coupled and electrically-tunable mechanical resonators on a single carbon nanotube for the first time. The frequency of the two resonators can be individually tuned by the bottom gates, and strong coupling is observed between the electron charge and phonon modes of each resonator. Furthermore, the conductance of either resonator can be nonlocally modulated by the phonon modes in the other resonator. Strong coupling is observed between the phonon modes of the two resonators, which provides an effective long distance electron-electron interaction. The generation of phonon-mediated-spin entanglement is also theoretically analyzed for the two resonators. This strongly-coupled nanotube electromechanical resonator array provides an experimental platform for future studies of the coherent electron-phonon interaction, the phonon mediated long-distance electron interaction, and entanglement state generation

The Sand Removal Performance and Erosion Characteristics of Shale Gas Wellhead Desander

In the process of shale gas extraction, fracturing technology is often used, and the extracted gas contains large amounts of sand, resulting in the risk of blockage and erosion of surface gathering equipment, which seriously affects safe production. To address this problem, this paper presents a numerical study of the sand removal performance and erosion characteristics of the filter desander used in Sichuan shale gas fields under different operating conditions (flow velocity, sand mass flow rate, operating pressure, and sand particle size) using CFD method. The results show that the increase of shale gas velocity is not conducive to the efficient operation of the filter desander. So the flow velocity should be controlled within 10 m/s as much as possible to avoid the rapid drawdown of separation efficiency and overly high erosion rate. When the sand size increases from 10μm to 100μm, the erosion area of the filter desander changes to sheet-like distribution, and the separation efficiency increases to 85%, a 2.3-fold increase. In addition, the change in operating pressure has a relatively small impact on the erosion wear of the desander