# Transit String Dark Energy Models in $f(Q)$ Gravity

## TL;DR

This paper explores an anisotropic $f(Q)$ gravity model with string fluid, constraining it with observational data, and finds it describes a quintessence dark energy universe with a transition phase.

## Contribution

It introduces a specific $f(Q)$ gravity model with string fluid, constrains it using observational data, and analyzes its cosmological implications including dark energy behavior.

## Key findings

- Model fits observational H(z) and SNe Ia data well.
- The universe exhibits a quintessence dark energy phase.
- The model indicates a transition phase in cosmic evolution.

## Abstract

In this paper, we have investigated an anisotropic cosmological model in $f(Q)$ gravity with string fluid in LRS Bianchi type-I universe. We have considered the arbitrary function $f(Q)=Q+\alpha\sqrt{~Q}+2\Lambda$ where $\alpha$ is model free parameter and $\Lambda$ is the cosmological constant. We have established a relationship between matter energy density parameter $\Omega_{m}$ and dark energy density parameter $\Omega_{\Lambda}$ through Hubble function using using constant equation of state parameter $\omega$. We have made observational constraint on the model using $\chi^2$-test with observed Hubble datasets $H(z)$ and SNe Ia datasets, and obtained the best fit values of cosmological parameters. We have used these best fit values in the result and discussion. We have discussed our result with cosmographic coefficients and found a transit phase dark energy model. Also, we analyzed the Om diagnostic function for anisotropic universe and found that our model is quintessence dark energy model.