RT Journal Article T1 Analogue gravity simulation of superpositions of spacetimes A1 Barceló, Carlos A1 Garay Elizondo, Luis Javier A1 García Moreno, Gerardo AB Taking the principles of quantum mechanics as they stand and applying them to gravity, leads to the conclusion that one might be able to generate superpositions of spacetimes, at least formally. We analyze such a possibility from an analogue gravity perspective. We present an analogue toy model consisting of a Bose-Einstein condensate in a double-well potential and identify the states that could potentially be interpreted as superposition of effective spacetimes. These states are unstable and the source of instability from a microscopic point of view can be related to the absence of a well-defined causal structure in the effective geometric description. We explore the consequences of these instabilities and argue that they resonate with Penrose's ideas about the decay that superpositions of states with sufficiently different gravitational fields associated should experience. PB Springer SN 1434-6044 YR 2022 FD 2022-08-20 LK https://hdl.handle.net/20.500.14352/73044 UL https://hdl.handle.net/20.500.14352/73044 LA eng NO © The Author(s) 2022GGM would like to thank Alfredo Luis for very useful discussions. Financial support was provided by the Spanish Government through the projects PID2020-118159GB-C43, PID2020118159GB-C44, FIS2017-86497-C2-1-P, FIS2017-86497-C2-2-P (with FEDERcontribution), and by the Junta deAndalucia through the project FQM219. CB and GGM acknowledge financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709). GGM is funded by the Spanish Government fellowship FPU20/01684. NO Ministerio de Ciencia e Innovación (MICINN)/ FEDER NO Ministerio de Ciencia e Innovación (MICINN)/AEI NO Ministerio de Universidades NO Junta de Andalucia NO Centros de Excelencia Severo Ochoa (MICINN) DS Docta Complutense RD 3 abr 2025