Optomechanical Schrödinger cats – a case for space

Abstract

Quantum optomechanics exploits radiation pressure effects inside optical cavities. It can be used to generate quantum states of the center-of-mass motion of massive mechanical objects, thereby opening up a new parameter regime for macroscopic quantum experiments. The challenging experimental conditions to maintain and observe quantum coherence for increasingly large objects may require a space environment rather than an earth-bound laboratory. We introduce a possible space experiment to study the wave-packet expansion of massive objects. This forms the basis for Schrödinger cat states of unprecedented size and mass.

Macroscopic Quantum Resonators (MAQRO): 2015 update

“…The stochastic momentum transfer in collapse models can lead to heating of the centre-of-mass motion of trapped nanospheres [50,51]. This can, in principle, be observed by comparing the measured noise spectra with theoretical predictions [52].…”

“…As in the frequency-based non-interferometric approach above, this method is based on the stochastic momentum transfer due to collapse mechanisms. In particular, the momentum transfer leads to a random walk resulting in an increased rate for the expansion of wavepackets [50,52,53].…”

“…This random walk can, in principle, be observed when comparing the expansion rate of a quantum wave packet with the predictions of quantum theory as well as with the predictions of alternative models. Apart from the original suggestion for such an experiment [50], there have also been more recent suggestions to observe this effect using free-falling or optically trapped, dielectric particles [52,53]. Even if there is no decoherence, the width of a quantum wave packet will expand over time according to the Schrödinger equation.…”

Quantum Physics in Space

“…Furthermore, many fundamental tests of physics require a micro-gravity environment (≤ 10 −9 g), long free-fall times (100 s), and a large number of repetitions (10 4 ) per measurement, which are more easily fulfilled with a space-based setup [221]. Over the years, the mission scenario MAQRO has been developed with these aims [8,147,[384][385][386][387][388][701][702][703][704][705]. Some aspects, especially the thermal shielding and how cold one can get in space, were studied numerically in detail.…”