We generalize Integration-By-Parts (IBP) and differential equations methods
to de Sitter amplitudes related to inflation. While massive amplitudes in de
Sitter spacetime are usually regarded as highly intricate, we find they have
remarkably hidden concise structures from the perspective of IBP. We find the
irrelevance of IBP relations to propagator-types. This also leads to the
factorization of the IBP relations of each vertex integral family corresponding
to $mathrm{d} tau_i$ integration. Furthermore, with a smart construction of
master integrals, the universal formulas for iterative reduction and
$mathrm{d} log$-form differential equations of arbitrary vertex integral
family are presented and proved. These formulas dominate all tree-level de
Sitter amplitude and play a kernel role at the loop-level as well.

Conclusions

The generalization of Integration-By-Parts (IBP) and differential equations methods to de Sitter amplitudes related to inflation has revealed the existence of hidden concise structures in massive amplitudes in de Sitter spacetime. These structures are not dependent on the type of propagator being used. Additionally, the IBP relations of each vertex integral family can be factorized with respect to integration over $mathrm{d} tau_i$. Moreover, the development of smart constructions of master integrals has led to the discovery of universal formulas for iterative reduction and $mathrm{d} log$-form differential equations for arbitrary vertex integral families.

Roadmap for Readers: Challenges and Opportunities

1. Understanding the Hidden Concise Structures

Readers should strive to gain a comprehensive understanding of the hidden concise structures found within massive amplitudes in de Sitter spacetime. This exploration presents an opportunity to further investigate the underlying principles behind these structures and their significance in the context of de Sitter amplitudes related to inflation.

2. Investigating the Irrelevance of IBP Relations to Propagator-Types

Exploring the irrelevance of IBP relations to propagator-types opens up avenues for studying the fundamental properties of de Sitter amplitudes and their behavior under different types of interactions. Readers should delve into the implications of this discovery and its potential implications in other areas of physics.

3. Factorization of IBP Relations and $mathrm{d} tau_i$ Integration

The factorization of IBP relations with respect to $mathrm{d} tau_i$ integration offers an opportunity to investigate the underlying mathematical properties and connections between different vertex integral families. Readers should explore the consequences of this factorization and its implications for the computation of de Sitter amplitudes.

4. Universal Formulas for Iterative Reduction and $mathrm{d} log$-Form Differential Equations

The discovery of universal formulas for iterative reduction and $mathrm{d} log$-form differential equations provides a powerful tool for analyzing and computing arbitrary vertex integral families. Readers should focus on understanding the applications of these formulas and their potential impact on the study of de Sitter amplitudes at both tree-level and loop-level.

5. Role of Universal Formulas in Tree-Level and Loop-Level Amplitudes

Investigating the role played by the universal formulas in tree-level and loop-level de Sitter amplitudes is crucial for understanding their significance and potential applications in cosmology and quantum field theory. Readers should explore the implications and limitations of these formulas in various physical scenarios.

6. Future Developments and Applications

As research in de Sitter amplitudes related to inflation progresses, there will be opportunities to develop new techniques and apply existing methods to address open questions in the field. Readers should stay updated with these advancements and contribute to further developments in this area of research.

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