arXiv subjects

Meng-Zhi Wu

Publications and source records attributed to Meng-Zhi Wu.

4 recordsLinked to original sources

arXiv2026

Acceleration Noise Induced Decoherence in Stern-Gerlach Interferometers for Gravity Experiments

Stern-Gerlach interferometer (SGI) is a kind of matter-wave interferometer driven by magnetic field and has been proposed for various gravity experiments. Stochastic noises can lead to decoherence problems of SGI via various mechanisms. In this paper, I will theoretically study several mechanisms including dephasing, contrast loss and position localisation decoherence. I will firstly present a rigorous proof that the dephasing behaves as a linear response to the noise, with a transfer function given by the Fourier transform of the unperturbed classical trajectories. Then I will demonstrate that stochastic acceleration noise only induces dephasing to the witness operator constructed in spin space, while it does not lead to contrast loss or position localisation decoherence due to common mode cancellation. In contrast, higher-order noise can induce both contrast loss and position localisation decoherence, contributing a decay factor proportional to the noise power spectrum density at the intrinsic frequency, which can be physically interpreted as the resonance between the noise and test mass. Based on the result, I apply the framework to analyse two typical noise sources, magnetic field noise and quadratic noise.

quant-ph↗

arXiv2025

Destructive Interference of Inertial Noise in Matter-wave Interferometry

Matter-wave interferometry is highly susceptible to inertial acceleration noises arising from the vibration of the experimental apparatus. There are various methods for noise suppression. In this paper, we propose leveraging the cross-correlation of multi-directional vibration noises to mitigate their dephasing effect in matter-wave interferometers. Specifically, we analyse an interferometer driven by its internal state under an external field and examine the dephasing caused by a two-dimensional random inertial force. As we will demonstrate, the coupling between the two-dimensional inertial force noise components will shift the resonance peak but not change the shape of the power spectral density. Moreover, when the noise approximately resonates with the intrinsic frequency of the test mass, we find that the standard deviation of the phase can be suppressed by a factor roughly equal to the Q-factor of the noise. This technique holds significant potential for future gravity experiments utilising quantum sensors, such as measuring gravitational acceleration and exploring quantum entanglement induced by gravity.

quant-ph↗

arXiv2025

Inertial Torsion Noise in Matter-Wave Interferometers for Gravity Experiments

Matter-wave interferometry is susceptible to non-inertial noise sources, which can induce dephasing and a resulting loss of interferometric visibility. Here, we focus on inertial torsion noise (ITN), which arises from the rotational motion of the experimental apparatus suspended by a thin wire and subject to random external torques. We provide analytical expressions for the ITN noise starting from generalized Langevin equations describing the experimental box which can then be used together with the transfer function to obtain the dephasing factor. We verify the theoretical modelling and the validity of the approximations using Monte Carlo simulations, obtaining good agreement between theory and numerics. As an application, we estimate the size of the effects for the next generation of interferometry experiments with femtogram particles, which could be used as the building block for entanglement-based tests of the quantum nature of gravity. We find that the ambient gas is a weak source of ITN, posing mild restrictions on the ambient pressure and temperature. We discuss the general ITN constraints by assuming a Langevin equation parameterized by three phenomenological parameters.

quant-ph↗

arXiv2023

Quantum Gravitational Sensor for Space Debris

Matter-wave interferometers have fundamental applications for gravity experiments such as testing the equivalence principle and the quantum nature of gravity. In addition, matter-wave interferometers can be used as quantum sensors to measure the local gravitational acceleration caused by external massive moving objects, thus lending itself for technological applications. In this paper, we will establish a three dimensional model to describe the gravity gradient signal from an external moving object, and theoretically investigate the achievable sensitivities using the matter-wave interferometer based on the Stern-Gerlach set-up. As an application we will consider the Mesoscopic Interference for Metric and Curvature (MIMAC) and Gravitational wave detection scheme [New J. Phys. 22, 083012 (2020)] and quantify its sensitivity to gravity gradients using frequency-space analysis. We will consider objects near Earth-based experiments and space debris in proximity of satellites and estimate the minimum detectable mass of the object as a function of their distance, velocity, and orientation.

gr-qc↗