Tachyon field in loop quantum cosmology: An example of traversable singularity

TL;DR

This paper explores a new quantization scheme in loop quantum cosmology using a tachyon field, demonstrating that the universe can pass through a quantum singularity that is weaker than classical big bang singularity.

Contribution

It provides a concrete example of a traversable quantum singularity in LQC using a tachyon field, highlighting a novel type of weak singularity.

Findings

Universe evolves through the quantum singularity regularly

The quantum singularity is weaker than classical big bang

Supports the viability of the new quantization scheme in LQC

Abstract

Loop quantum cosmology (LQC) predicts a nonsingular evolution of the universe through a bounce in the high energy region. But LQC has an ambiguity about the quantization scheme. Recently, the authors in [Phys. Rev. D 77, 124008 (2008)] proposed a new quantization scheme. Similar to others, this new quantization scheme also replaces the big bang singularity with the quantum bounce. More interestingly, it introduces a quantum singularity, which is traversable. We investigate this novel dynamics quantitatively with a tachyon scalar field, which gives us a concrete example. Our result shows that our universe can evolve through the quantum singularity regularly, which is different from the classical big bang singularity. So this singularity is only a week singularity.