Quantum entanglement enables single-shot trajectory sensing for weakly interacting particles

TL;DR

This paper demonstrates that quantum entanglement in multi-qubit sensors enables single-shot, highly accurate trajectory sensing of particles, significantly reducing the interaction strength needed compared to unentangled sensors.

Contribution

It establishes that entanglement allows perfect trajectory discrimination with minimal interaction strength and enables single-shot sensing in scenarios where unentangled sensors require multiple repetitions.

Findings

Entanglement reduces the interaction threshold for perfect discrimination.

Entangled sensors can succeed with zero error in a single shot.

Entanglement enhances sensing in realistic, variable interaction scenarios.

Abstract

Sensors for mapping the trajectory of an incoming particle find important utility in experimental high energy physics and searches for dark matter. For a quantum sensing protocol that uses projective measurements on a multi-qubit sensor array to infer the trajectory of an incident particle, we establish that entanglement can dramatically reduce the particle-qubit interaction strength $\theta$ required for perfect trajectory discrimination. Within an interval of $\theta$ above this reduced threshold, any unentangled sensor requires $\Theta(\log(1/\epsilon))$ repetitions of the protocol to estimate a previously unknown particle trajectory with $\epsilon$ error probability, whereas an entangled sensor can succeed with zero error in a single shot. Furthermore, entanglement can enhance trajectory sensing in realistic scenarios where $\theta$ varies continuously over the sensor qubits, exemplified by a Gaussian-profile laser pulse propagating through an array of atoms.