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arXiv · 2503.20707

Accelerated State Expansion of a Nanoparticle in a Dark Inverted Potential

Gregoire F. M. Tomassi·Daniel Veldhuizen·Bruno Melo·Davide Candoli·Andreu Riera-Campeny·Oriol Romero-Isart·Nadine Meyer·Romain Quidant
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Abstract

While the wave packet of a massive particle grows linearly under free dynamics, it grows exponentially in an inverted harmonic potential, offering a pathway to rapidly increase quantum fluctuations to macroscopic dimensions. In this work, we experimentally demonstrate this principle by expanding the center-of-mass thermal state of a 125nm silica nanoparticle to a position uncertainty of 43.4nm within 260 $\mu$s. This expansion, achieved using an inverted dark potential to minimize decoherence from photon recoil, represents a 952-fold increase, reaching a scale comparable to the nanoparticle's physical size. This work represents a key advancement toward preparing macroscopic quantum superpositions at unprecedented mass and length scales.

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Gregoire F. M. Tomassi, Daniel Veldhuizen, Bruno Melo, Davide Candoli, Andreu Riera-Campeny, Oriol Romero-Isart, Nadine Meyer, Romain Quidant. 2025-03-26. Accelerated State Expansion of a Nanoparticle in a Dark Inverted Potential. https://arxiv.org/abs/2503.20707

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