A roadmap for universal high-mass matter-wave interferometry

Abstract

Creating quantum superposition states of bodies with increasing mass and complexity is an exciting and important challenge. Demonstrating such superpositions is vital for understanding how classical observations arise from the underlying quantum physics. Here, we discuss how recent progress in macromolecule interferometry can be combined with the state of the art in cluster physics to push the mass record for matter-wave interference with wide state separation by 3 to 4 orders of magnitude. We show how near-field interferometers in different configurations can achieve this goal for a wide range of particle materials with strongly varying properties. This universality will become important in advanced tests of wave function collapse and of other modifications of quantum mechanics, as well as in the search for light dark matter and in tests of gravity with composite quantum systems.

Multi-Watt cavity for 266 nm light in vacuum

“…To mend this, we would have to remove all hydrocarbons from the vacuum setup [11,32]. However, as the purpose of the cavity is to provide an intense laser grating for matter-wave diffraction of large organic molecules [37,38], this is not an option. Flushing the mirrors with oxygen has to be discarded as well, as the resulting increase in pressure would induce collisional decoherence of the matter-wave [39].…”

Internal decoherence in nano-object interferometry due to phonons

“…Due to the finite interaction time, the Fourier transform ã(ω) is band-limited to ω∆t < ∼ 1. For a small object, the fundamental tone ω 1 is beyond this limit, and the sum (19) over eigenfrequencies converges rapidly with only a few terms contributing significantly. In the acoustic spectrum of a sphere, it is therefore sufficient to keep only the two lowest acoustic eigenfrequencies (torsional and spheroidal d-waves, see Fig.…”

“…In the acoustic spectrum of a sphere, it is therefore sufficient to keep only the two lowest acoustic eigenfrequencies (torsional and spheroidal d-waves, see Fig. 1) when evaluating the contrast (19).…”

“…Spatial quantum superpositions have so far been tested only with small systems, from photons [1] and elementary particles [2][3][4][5] to atoms [6][7][8] and molecules [9,10]. Such superpositions for massive objects have been a long-standing sought-after goal [11][12][13][14][15][16][17][18][19]. This is important not only in order to confirm quantum theory in new regimes, but also in order to probe the quantum-gravity interface.…”

“…In addition, such an experiment will enable to test exotic theories [20][21][22][23][24], and may even enable new technology [25]. Creating such superpositions is notoriously hard because of environmental decoherence [19,22,[26][27][28][29][30], whereby the large object couples strongly to the environment which turns the delicate quantum state into a statistical mixture (classical state). However, advances in the technology of isolation could in future suppress such decoherence.…”