Could Levitated Nanoparticles Test Spontaneous Wave-Function Collapse?

Anonymous

Ondřej Černotík, Radim Filip

Andrea Vinante, Giulio Gasbarri, Chris Timberlake +2 more

We present experimental tests of dissipative extensions of spontaneous wave function collapse models based on a levitated micromagnet with ultralow dissipation. The spherical micromagnet, with radius R = 27 µm, is levitated by Meissner effect in a lead trap at 4.2 K and its motion is detected by a SQUID. We perform accurate ringdown measurements on the vertical translational mode with frequency 57 Hz, and infer the residual damping at vanishing pressure γ/2π < 9 µHz. From this upper limit we derive improved bounds on the dissipative versions of the CSL (continuous spontaneous localization) and the DP (Di´osi-Penrose) models. In particular, dissipative models give rise to an intrinsic damping of an isolated system with the effect parameterized by a temperature constant – the dissipative CSL model with temperatures below 1 nK is ruled out, while the dissipative DP model is excluded for temperatures below 10−13 K. Furthermore, we present the first bounds on dissipative effects in a more recent model, which relates the wave function collapse to fluctuations of a generalized complex-valued spacetime metric.

A. Pontin, Nathanaël P. Bullier, Marko Toroš +1 more

This work measures dissipation affecting a nano-particle levitated in a Paul trap in high vacuum. By evaluating the energy power spectral density of the resulting low frequency harmonic oscillator, the authors spectrally resolve an ultra-narrow linewidth of 80 \textmu{}Hz. These measurements are then used to place bounds on two wavefunctions collapse models in their dissipative variants, namely the continuous spontaneous localization and the Di\'osi-Penrose model

Uroš Delić

Andrea Vinante, A. Pontin, Muddassar Rashid +3 more

Collapse models, proposed to explain the absence of quantum superpositions at macroscopic scales, generically predict the existence of random forces on a massive object. Here, detection of levitated particle motion is explored though three different approaches based on an optical cavity, an optical tweezer, and an electrical readout exploiting a SQUID. These approaches are analyzed and compared, and the advantages, drawbacks, and technical challenges are assessed.