# Physical condition for the slowing down of cosmic acceleration

## TL;DR

This paper investigates whether cosmic acceleration is slowing down using a model-independent approach, finding no evidence for slowdown within current observational data and explaining the source of previous model tensions.

## Contribution

It introduces a derivative analysis of the deceleration parameter to clarify tensions and limitations in current data regarding cosmic acceleration slowdown.

## Key findings

- No evidence of slowing down within 95% confidence level.
- Identifies the source of tension between different dark energy models.
- Current data are insufficient to convincingly measure acceleration slowdown.

## Abstract

The possible slowing down of cosmic acceleration was widely studied. However, the imposition of dark energy parametrization brought some tensions. In our recent paper, we test this possibility using a model-independent method, Gaussian processes. However, the reason of generating these tensions is still closed. In the present paper, we analyse the derivative of deceleration parameter to solve the problems. The reconstruction of the derivative again suggests that no slowing down of acceleration is presented within 95\% C.L. from current observational data. We then deduce its constraint on dark energy. The corresponding constraint clearly reveals the reason of tension between different models in previous work. We also study the essential reason of why current data cannot convincingly measure the slowing down of acceleration. The constraints indicate that most of current data are not in the allowed region.