What phenomenon supports a White Dwarf against further gravitational collapse?

Electron degeneracy pressure

A White Dwarf represents the remnant core of a low-to-intermediate mass star, packed into a volume roughly the size of Earth despite containing solar mass material. This extreme compactness is only resisted by a quantum mechanical effect known as electron degeneracy pressure. This pressure arises because the electrons within the matter cannot be squeezed into the same quantum states according to the Pauli exclusion principle, creating an outward resistance that successfully halts the relentless crushing force of gravity once fusion energy production has ceased. If this pressure were overcome, the object would proceed to collapse further, likely into a neutron star, but this specific quantum resistance is what defines the stable end state of stellar embers like the Sun's future corpse.