ELFT HÍRADÓ

[Janos Asboth <asboth AT phy.bme.hu>]

Meghívó

BME Elméleti Fizika Szeminárium,

október 30. péntek 10h15,
online a Microsoft Teamsben,
<https://teams.microsoft.com/l/meetup-join/19%3a7a54b9ebcb224a8fa118a1572f5e20e4%40thread.tacv2/1603827818167?context=%7b%22Tid%22%3a%226a3548ab-7570-4271-91a8-58da00697029%22%2c%22Oid%22%3a%22c7eaf7d2-684b-4597-b217-6a9121400219%22%7d>

Diósi Lajos (Wigner FK):

Schrödinger's Cats remain afraid of gravity!

Standard quantum theory allows for superpositions of macroscopically
different states of macroscopic objects. Such states, called Schrödinger's
Cats, collapse under standard quantum measurements. Massive Schrödinger
Cats are relevant and problematic in quantum gravity, and also remain
problematic in the Newtonian non-relativistic limit. The speaker [1] and
Penrose [2] have introduced a tiny universal decoherence - proportional to
Newton's constant G - to modify the standard unitary qauntum dynamics.
Accordingly, any Schrödinger Cat collapses spontaneously, without any
measurement. After 30 years, dedicated tests using quantum nanomechanics
are under construction or planning in earth- (e.g. [3]) as well as in
space-based labs (e.g. [4]), results are expected in the coming years.
Indirect tests were already reported (e.g. [5] based on Lisa Pathfinder's
data) to constrain the short-length cutoff parameter of the theory. A most
recent indirect test in the Gran Sasso underground lab [6], co-authored by
the speaker, has led to headlines, raising the question whether collapse of
Schrödinger Cats has anything to do with gravity.

[1] Diosi, PLA 120,377 (1987)
[2] Penrose, GRG 28, 581 (1996)
[3] Pontin et al, PRR 2, 023349 (2020)
[4] Kaltenbaek et al, EPJ Quant.Tech. 3:5 (2016)
[5] Helou et al, PRD 95, 084054 (2017)
[6] Donadi et al, Nat.Phys. https://doi.org/10.1038/s41567-020-1008-4 (2020)

Minden érdeklődőt szeretettel várunk.

Asbóth János
szemináriumi koordinátor