Mass eigenstates in bimetric theory with matter coupling

Journal Article · Thu Jan 01 04:00:00 EST 2015 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2015/01/039· OSTI ID:22382012

Schmidt-May, Angnis ^[1]

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1. Department of Physics and The Oskar Klein Centre, Stockholm University, AlbaNova University Centre, Stockholm, SE-106 91 Sweden (Sweden)

In this paper we study the ghost-free bimetric action extended by a recently proposed coupling to matter through a composite metric. The equations of motion for this theory are derived using a method which avoids varying the square-root matrix that appears in the matter coupling. We make an ansatz for which the metrics are proportional to each other and find that it can solve the equations provided that one parameter in the action is fixed. In this case, the proportional metrics as well as the effective metric that couples to matter solve Einstein's equations of general relativity including a matter source. Around these backgrounds we derive the quadratic action for perturbations and diagonalize it into generalized mass eigenstates. It turns out that matter only interacts with the massless spin-2 mode whose equation of motion has exactly the form of the linearized Einstein equations, while the field with Fierz-Pauli mass term is completely decoupled. Hence, bimetric theory, with one parameter fixed such that proportional solutions exist, is degenerate with general relativity up to linear order around these backgrounds.

• OSTI ID: 22382012
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 01 Vol. 2015; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COUPLING
EIGENSTATES
EINSTEIN FIELD EQUATIONS
EQUATIONS OF MOTION
GENERAL RELATIVITY THEORY
MASS
MATHEMATICAL SOLUTIONS
MATRICES
MATTER
METRICS
PERTURBATION THEORY
SPIN