Momentum-space Aharonov-Bohm interferometry in Rashba spin-orbit coupled Bose-Einstein condensates

Since the recent experimental realization of synthetic Rashba spin-orbit coupling paved a new avenue for exploring and engineering topological phases in ultracold atoms, a precise, solid detection of Berry phase has been desired for unequivocal characterization of system topology. Here, we propose a scheme to conduct momentum-space Aharonov-Bohm interferometry in a Rashba spin-orbit coupled Bose-Einstein condensate with a sudden change of in-plane Zeeman field, capable of measuring the Berry phase of Rashba energy bands. We find that the Berry phase with the presence of a Dirac point is directly revealed by a robust dark interference fringe, and that as a function of external Zeeman field is characterized by the contrast of fringes. We also build a variational model describing the interference process with semiclassical equations of motion of essential dynamical quantities, which lead to agreeable trajectories and geometric phases with the real-time simulation of Gross-Pitaevskii equation. Our study would provide timely guidance for the experimental detection of Berry phase in ultracold atomic systems and help further investigation on their interference dynamics in momentum space.Comment: 9 pages, 6 figure

A filtering method based on wavelet transform for collected data of automatic ammunition loading system

Embedded fault diagnosis machine for the automatic ammunition loading system real-time monitors the automatic ammunition loading system, collects the data by using sensors, analyzes the data, detects and isolates faults, or predicts the health of the system in the future. The denoising of the collected data is of great significance to effectively reveal the operation information of ammunition automatic loading system. In order to solve the problem of the traditional median filter could not be taken into account the details and the smoothness, a filtering method based on wavelet transform for automatic ammunition loading system is proposed in this paper. This method can effectively reduce the noise and improve the signal noise ratio (SNR), the signal after wavelet filter retains all the low frequency of the single axis swing, filters out the high frequency noise. It ensures the correctness of the follow-up data analysis and processing, detection, isolation of the fault or predict the health of the system

Sliding mode control of a 2-DOF manipulator with random base vibration based on modified exponential reaching law

To solve the precise position control problem of a two degree of freedom (2-DOF) manipulator with random base vibration, a sliding mode control method based on modified exponential reaching law is studied. The dynamic model of manipulator is established by using the second kind Lagrange equation. The nonlinear term generated by base random vibration is presented as external disturbance term. Based on dynamic models, the sliding mode control using improved exponential reaching law is applied in the manipulator system. It is verified by the simulation result that the control method can effectively suppress the influence of base random vibration, and bring the manipulator from a given initial state to a prescribed terminal state rapidly and precisely