Generalized Uncertainty Principle and White Dwarfs Redux: How Cosmological Constant Protects Chandrasekhar Limit

TL;DR

This paper demonstrates that including a cosmological constant in the generalized uncertainty principle can restore the Chandrasekhar limit for white dwarfs, providing an upper bound on the cosmological constant based on white dwarf existence.

Contribution

It introduces an alternative method using extended GUP with a cosmological constant to preserve the Chandrasekhar limit, contrasting previous approaches with negative GUP parameters.

Findings

A small nonzero cosmological constant restores the Chandrasekhar limit.

White dwarf existence constrains the upper bound of the cosmological constant.

The bound is significantly smaller than the natural scale, yet still large compared to observations.

Abstract

It was previously argued that generalized uncertainty principle (GUP) with a positive parameter removes the Chandrasekhar limit. One way to restore the limit is by taking the GUP parameter to be negative. In this work we discuss an alternative method that achieves the same effect: by including a cosmological constant term in the GUP (known as "extended GUP" in the literature). We show that an arbitrarily small but nonzero cosmological constant can restore the Chandrasekhar limit. We also remark that if the extended GUP is correct, then the existence of white dwarfs gives an upper bound for the cosmological constant, which -- while still large compared to observation -- is approximately 86 orders of magnitude smaller than the natural scale.