Coupling Quantum Matter and Gravity

authored by: Domenico Giulini, André Großardt, Philip K. Schwartz
Abstract: In this contribution we deal with several issues one encounters when trying to couple quantum matter to classical gravitational fields. We start with a general background discussion and then move on to two more technical sections. In the first technical part we consider the question how the Hamiltonian of a composite two-particle system in an external gravitational field can be computed in a systematic post-Newtonian setting without backreaction. This enables us to reliably estimate the consistency and completeness of less systematic and more intuitive approaches that attempt to solve this problem by adding ‘relativistic effects’ by hand. In the second technical part we consider the question of how quantum matter may act as source for classical gravitational fields via the semiclassical Einstein equations. Statements to the effect that this approach is fundamentally inconsistent are critically reviewed.
Organisation(s): CRC 1227 Designed Quantum States of Matter (DQ-mat)
Institute of Theoretical Physics
QuantumFrontiers
External Organisation(s): Friedrich Schiller University Jena
Center of Applied Space Technology and Microgravity (ZARM)
VolkswagenStiftung
University of Bremen
Type: Contribution to book/anthology
Pages: 491-550
No. of pages: 60
Publication date: 01.10.2023
Publication status: Published
ASJC Scopus subject areas: Physics and Astronomy (miscellaneous)
Electronic version(s): https://arxiv.org/abs/2207.05029 (Access: Open)
https://doi.org/10.1007/978-3-031-31520-6_16 (Access: Closed)

BibTeX

@inbook{dbe1046402d94f82ae0df990ae8889f1,
title = "Coupling Quantum Matter and Gravity",
abstract = "In this contribution we deal with several issues one encounters when trying to couple quantum matter to classical gravitational fields. We start with a general background discussion and then move on to two more technical sections. In the first technical part we consider the question how the Hamiltonian of a composite two-particle system in an external gravitational field can be computed in a systematic post-Newtonian setting without backreaction. This enables us to reliably estimate the consistency and completeness of less systematic and more intuitive approaches that attempt to solve this problem by adding {\textquoteleft}relativistic effects{\textquoteright} by hand. In the second technical part we consider the question of how quantum matter may act as source for classical gravitational fields via the semiclassical Einstein equations. Statements to the effect that this approach is fundamentally inconsistent are critically reviewed.",
author = "Domenico Giulini and Andr{\'e} Gro{\ss}ardt and Schwartz, {Philip K.}",
note = "Funding information: A. G. acknowledges funding from the VolkswagenStiftung. D. G. and P. K. S. acknowledge support from the Deutsche Forschungsgemeinschaft via the Collaborative Research Centre 1227 {\textquoteleft}DQ-mat{\textquoteright}, projects A05 and B08, at Leibniz University Hannover. All three authors would like to thank the organisers of the 740th WE-Heraeus-Seminar {\textquoteleft}Experimental Tests and Signatures of Modified and Quantum Gravity{\textquoteright} for the opportunity to present and discuss the topics which laid the foundation for this work.",
year = "2023",
month = oct,
day = "1",
doi = "10.1007/978-3-031-31520-6_16",
language = "English",
isbn = "978-3-031-31519-0",
series = "Lecture Notes in Physics",
publisher = "Springer, Cham",
pages = "491--550",
editor = "Christian Pfeifer and Claus L{\"a}mmerzahl",
booktitle = "Modified and Quantum Gravity",
}