arXiv subjects

Patrik Schach

Publications and source records attributed to Patrik Schach.

4 recordsLinked to original sources

arXiv2025

Spatial and Pulse Efficiency Constraints in Atom Interferometric Gravitational Wave Detectors

Currently planned and constructed terrestrial detectors for gravitational waves and dark matter based on differential light-pulse atom interferometry are designed around three primary strategies to enhance their sensitivity: (i) Resonant-mode enhancement using multiple diamonds, (ii) large-momentum-transfer techniques to increase arm separation within the interferometer, and (iii) very-long baseline schemes that increase the distance between the two interferometers. Both resonant-mode enhancement and large-momentum-transfer techniques result in a greater number of light pulses, making high pulse fidelity during atom-light interactions imperative. At the same time, increasing the number of diamonds in vertical configurations leads to taller atomic fountains, which consequently reduces the available distance between interferometers. As a result, the number of diamonds, large-momentum-transfer pulses, and the fountain height are interdependent parameters that must be carefully balanced. In this work, we present optimal configurations for multi-diamond geometries, explicitly accounting for the spatial extent of a single interferometer, considering constraints imposed by the baseline dimensions and atomic losses due to imperfect pulses. We provide practical analytical relations to estimate the optimal number of pulses that should be applied. Many proposals beyond demonstrator experiments require pulse numbers that demand efficiencies not yet demonstrated with state-of-the-art momentum transfer techniques. As a result, the observed sensitivity falls short of expectations - an effect caused by both arm separation and atom loss per pulse - highlighting the urgent need for research aimed at improving pulse fidelities.

quant-ph↗

arXiv2025

Dichroic mirror pulses for optimized higher-order atomic Bragg diffraction

Increasing the sensitivity of light-pulse atom interferometers progressively relies on large-momentum transfer techniques. Precise control of such methods is imperative to exploit the full capabilities of these quantum sensors. One key element is the mitigation of deleterious effects such as parasitic paths deteriorating the interferometric signal. In this Letter, we present the experimental realization of dichroic mirror pulses for atom interferometry, its scalability to higher-order Bragg diffraction, and its robustness against initial momentum spread. Our approach selectively reflects resonant atom paths into the detected interferometer output, ensuring that these contribute to the signal with intent. Simultaneously, parasitic paths are efficiently transmitted by the mirror and not directed to the relevant interferometer outputs. This method effectively isolates the desired interferometric signal from noise induced by unwanted paths. It can be readily applied to existing setups capable of higher-order Bragg diffraction.

quant-ph↗

arXiv2024

A unified theory of tunneling times promoted by Ramsey clocks

What time does a clock tell after quantum tunneling? Predictions and indirect measurements range from superluminal or instantaneous tunneling to finite durations, depending on the specific experiment and the precise definition of the elapsed time. Proposals and implementations utilize the atomic motion to define this delay, even though the inherent quantum nature of atoms implies a delocalization and is in sharp contrast to classical trajectories. Here, we rely on an operational approach: we prepare atoms in a coherent superposition of internal states and study the time read off via a Ramsey sequence after the tunneling process without the notion of classical trajectories or velocities. Our operational framework (a) unifies definitions of tunneling delay within one approach; (b) connects the time to a frequency standard given by a conventional atomic clock which can be boosted by differential light shifts; and (c) highlights that there exists no superluminal or instantaneous tunneling.

quant-ph↗

arXiv2022

Tunneling Gravimetry

We examine the prospects of utilizing matter-wave Fabry-Pérot interferometers for enhanced inertial sensing applications. Our study explores such tunneling-based sensors for the measurement of accelerations in two configurations: (a) a transmission setup, where the initial wave packet is transmitted through the cavity and (b) an out-tunneling scheme with intra-cavity generated initial states lacking a classical counterpart. We perform numerical simulations of the complete dynamics of the quantum wave packet, investigate the tunneling through a matter-wave cavity formed by realistic optical potentials and determine the impact of interactions between atoms. As a consequence we estimate the prospective sensitivities to inertial forces for both proposed configurations and show their feasibility for serving as inertial sensors.

quant-ph↗