Interactions of Multiple Spin-2 Fields beyond Pairwise Couplings

Area of Science:

• Theoretical Physics
• High-Energy Physics
• Quantum Field Theory

Background:

• Existing ghost-free theories for multiple spin-2 fields are limited to pairwise couplings.
• These pairwise couplings are direct extensions of bimetric interactions.
• A need exists for theories with genuine multifield interactions that avoid ghost instabilities.

Purpose of the Study:

• To present a novel class of spin-2 theories featuring genuine multifield interactions.
• To demonstrate the absence of ghost instabilities in these new theories.
• To explore the nature of the generated multivierbein interactions.

Main Methods:

• Constructing new spin-2 theories by integrating out a nondynamical field.
• Starting with a theory of spin-2 fields that possesses only pairwise ghost-free interactions.
• Analyzing the resulting interactions for the presence of ghost instabilities.

Main Results:

• A class of spin-2 theories with genuine multifield interactions has been successfully constructed.
• The absence of ghost instabilities in these novel theories is explicitly demonstrated.
• The newly generated multivierbein interactions are shown not to be universally expressible in terms of associated metrics.

Conclusions:

• The study successfully introduces a new framework for multifield spin-2 theories beyond pairwise interactions.
• The demonstrated absence of ghost instabilities validates the proposed construction.
• The findings open new avenues for exploring complex field interactions in theoretical physics.