# Exploring the deviation of cosmological constant by a generalized pressure dark energy model

## TL;DR

This paper introduces a generalized pressure dark energy (GPDE) model to study universe evolution, showing it can mimic quintessence or phantom fields, with observational constraints indicating a universe leaning towards quintessence and potential future rip scenarios.

## Contribution

The paper develops a unified GPDE model covering common pressure parameterizations, reconstructs it as scalar fields, and constrains it using cosmic data, revealing its compatibility with $ ext{Lambda}$CDM and possible future fates.

## Key findings

- GPDE model fits late-universe data within 1$\sigma$
- Model aligns with $ ext{Lambda}$CDM when combined with Planck data
- Future universe scenarios include pseudo rip, little rip, and big rip

## Abstract

We bring forward a generalized pressure dark energy (GPDE) model to explore the evolution of the universe. This model has covered three common pressure parameterization types and can be reconstructed as quintessence and phantom scalar fields, respectively. We adopt the cosmic chronometer (CC) datasets to constrain the parameters. The results show that the inferred late-universe parameters of the GPDE model are (within $1\sigma$): The present value of Hubble constant $H_{0}=(72.30^{+1.26}_{-1.37})$km s$^{-1}$ Mpc$^{-1}$; Matter density parameter $\Omega_{\text{m0}}=0.302^{+0.046}_{-0.047}$, and the universe bias towards quintessence. While when we combine CC data and the $H_0$ data from Planck, the constraint implies that our model matches the $\Lambda$CDM model nicely. Then we perform dynamic analysis on the GPDE model and find that there is an attractor or a saddle point in the system corresponding to the different values of parameters. Finally, we discuss the ultimate fate of the universe under the phantom scenario in the GPDE model. It is demonstrated that three cases of pseudo rip, little rip, and big rip are all possible.