Improve the performance of interferometer with ultra-cold atoms*

Abstract

Ultra-cold atoms provide ideal platforms for interferometry. The macroscopic matter-wave property of ultra-cold atoms leads to large coherent length and long coherent time, which enable high accuracy and sensitivity to measurement. Here, we review our efforts to improve the performance of the interferometer. We demonstrate a shortcut method for manipulating ultra-cold atoms in an optical lattice. Compared with traditional ones, this shortcut method can reduce the manipulation time by up to three orders of magnitude. We construct a matter-wave Ramsey interferometer for trapped motional quantum states and significantly increase its coherence time by one order of magnitude with an echo technique based on this method. Efforts have also been made to enhance the resolution by multimode scheme. Application of a noise-resilient multi-component interferometer shows that increasing the number of paths could sharpen the peaks in the time-domain interference fringes, which leads to a resolution nearly twice compared with that of a conventional double-path two-mode interferometer. With the shortcut method mentioned above, improvement of the momentum resolution could also be fulfilled, which leads to atomic momentum patterns less than 0.6 ℏkL . To identify and remove systematic noises, we introduce the methods based on the principal component analysis (PCA) that reduce the noise in detection close to the 1 / 2 of the photon-shot noise and separate and identify or even eliminate noises. Furthermore, we give a proposal to measure precisely the local gravity acceleration within a few centimeters based on our study of ultracold atoms in precision measurements.

Effects and Prospects of the Vibration Isolation Methods for an Atomic Interference Gravimeter

“…In the detection area, the time of flight method (TOF) is employed to detect the fluorescence signal of atoms, and obtain the normalized atomic transition probability P of atoms in two states [33,69,70]. In this case, P represents the probability of atomic interference in the macroscopic observable, and can be described by the following function:…”

The scientific career and contributions of Prof. Wang Yiqiu

“…Recently, BECs have also been used for precise measurements. Zhou's group has constructed a compact BEC gravimeter based on the Ramsey-Bordé approach by two pairs of/2 Raman pulses to get a small volume [115]. Between the two pairs of/2 Raman pulses, the Bloch oscillation caused by the accelerated optical lattice was carried out.…”

“…Between the two pairs of/2 Raman pulses, the Bloch oscillation caused by the accelerated optical lattice was carried out. This BEC gravimeter is expected to reach sub-μGal with atoms falling a distance of 2 cm [115]. In addition, Zhou's group is also building a BEC gyroscope based on the momentum states of the optical lattice.…”

Atomic transport dynamics in crossed optical dipole trap

“…Unlike magnetic traps, CODTs are not selective about the magnetic energy levels of atoms, making them ideal for quantum simulations of different spin states or spinors [18][19][20][21] and quantum precision measurement. [22][23][24][25][26] A CODT consists of two separate optical traps intersecting at their waists, creating a harmonic oscillator trap at the center and one pair of tubular crossed arms. The transport process of atoms in the CODT is accompanied by atomic loss from the trap and atomic loading from the arms to the central region of the CODT.…”