Calculating the Effective Center Wavelength for Heterodyne Interferometry of an Optical Frequency Comb

Heterodyne interferometry based on an optical frequency comb (OFC) is a powerful tool for distance measurement. In this paper, a method to calculate the effective center wavelength of wide spectrum heterodyne interference signal was explored though both simulation and experiment. Results showed that the effective center wavelength is a function of the spectra of the two interfered beams and time-delay of the two overlapped pulses. If the product of the spectra from two arms is symmetric, the effective center wavelength does not change with time-delay of the two pulses. The relative difference between the simulation and experiment was less than 0.06%.

Electrical control of strong spin-phonon coupling in a carbon nanotube

We describe an approach to electrically control the strong interaction between a single electron spin and the vibrational motion of a suspended carbon nanotube resonator. The strength of the deflection-induced spin-phonon coupling is dependent on the wavefunction of the electron confined in a lateral carbon nanotube quantum dot. An electrical field along the nanotube shifts the effective center of the quantum dot, leading to the corresponding modification of the spin-phonon strength. Numerical simulations with experimentally reachable parameters show that high fidelity quantum state transfer between mechanical and spin qubits driven by electrical pulses is feasible. Our results form the basis for the fully electrical control of the coherent interconvertion between light and spin qubits and for manufacturing electrically driven quantum information processing systems.

The Public and Personal Faces of the Church: Xu Zongze’s Sui si sui bi and the Shengjiao zazhi (Revue Catholique)

For the greater part of his adult life, the polymath Roman Catholic theologian Xu Zongze (P. Joseph Zi, S.J., 1886–1947) edited the premier Catholic journal Shengjiao zazhi, or Revue Catholique, from the Jesuit compound in Shanghai, the effective center of the Chinese Roman Catholic world. The directions in which he guided the magazine and the theological, historical, and social articles he wrote offer important insight into the evolution of Chinese Catholicism during the 1920s and 1930s. This chapter sets Xu’s biji, or “thoughts and jottings,” against his “official” magazine essays to explore the congruence or tension between the two voices, and suggests that the theologian and archivist was able to express himself differently in different forms. The unofficial, low-brow jottings constitute a personal view, in a Chinese form, to complement the official (Western-style) theological essays of the magazine.

Single charge exchange in collision of fast protons with hydrogen molecules

Single charge transfer process in collision of energetic protons with molecular hydrogens is theoretically studied using a first-order two-effective-center Born approximation. The correct boundary conditions are incorporated in the formalism and the Hartree–Fock molecular wave function for molecular targets and the residual ions are used to calculate the transition amplitude. The interference patterns in the capture differential cross-sections (DCSs) for a given fixed orientation of the molecule, due to the scattering from the two-atomic centers in the molecular targets, are examined. The dependence of the DCSs upon the angle between the molecular axis and the direction of the incident velocity is theoretically investigated. Both average differential and integral cross-sections are calculated. The obtained results are compared with the available experimental data.