Catálogo de publicaciones - revistas

<jats:p>Spin squeezing is a fascinating manifestation of many-particle entanglement and one of the most promising quantum resources. In this paper, we propose a novel realization of a solid-state quantum spin squeezing by applying SiV centers embedded in a diamond waveguide with the help of a microwave field. The phenomena about the generation of spin squeezing are analyzed numerically in Markovian environments. Our analysis shows that spin squeezing can be generated with the microwave field’s help under some realistic conditions, despite the presence of dephasing and mechanical damping. This solid-state spin squeezing based on SiV centers in diamonds might be applied to magnetometers, interferometry, and other precise measurements.</jats:p>

<jats:p>By utilizing the extended phase-matching (EPM) method, we investigate the generation of single photons with high spectral-purity in a magnesium-doped periodically-poled lithium niobate (MgO:PPLN) crystal via the spontaneous parametric down-conversion (SPDC) process. By adjusting the temperature and pump wavelength, the wavelength of the single photons can be tuned from telecom to mid-infrared (MIR) wavelengths, for which the spectral-purity can be above 0.95 with high transmission filters. In experiments, we engineer a MgO:PPLN with poling period of 20.35 μm which emits the EPM photon pair centered at 1496.6 nm and 1644.0 nm and carry out the joint spectral intensity (JSI) and Glauber’s second-order self-correlation measurements to characterize the spectral purity. The results are in good agreement with the numerical simulations. Our work may provide a valuable approach for the generation of spectrally pure single photons at a wide range of wavelengths which is competent for various photonic quantum technologies.</jats:p>

<jats:p>Collective motion of active particles with polar alignment is investigated on a sphere. We discussed the factors that affect particle swarm motion and define an order parameter that can show the degree of particle swarm motion. In the model, we added a polar alignment strength, along with Gaussian curvature, affecting particles swarm motion. We find that when the force exceeds a certain limit, the order parameter will decrease with the increase of the force. Combined with our definition of order parameter and observation of the model, the reason is that particles begin to move side by side under the influence of polar forces. In addition, the effects of velocity, rotational diffusion coefficient, and packing fraction on particle swarm motion are discussed. It is found that the rotational diffusion coefficient and the packing fraction have a great influence on the clustering motion of particles, while the velocity has little influence on the clustering motion of particles.</jats:p>