degeneracy pressure

American  

noun

1. Physics. the outward pressure exerted by fermions in dense material, conforming to the Pauli exclusion principle that in any system described by quantum mechanics no two identical particles having spin equal to half an odd integer can be in the same quantum state.

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degeneracy pressure Scientific  

/ dĭ-jĕn′ər-ə-sē /

1. A pressure exerted by dense material consisting of fermions (such as electrons in a white dwarf star). This pressure is explained in terms of the Pauli exclusion principle, which requires that no two fermions be in the same quantum state. The more densely fermions are packed together and must share the same space, the more they must differ from each other in terms of their momentum. In turn, the greater the range in momentum, the greater the fraction of particles with high momentum, and these exert pressure on their surroundings.

2. See also neutron star white dwarf

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Example Sentences

Normally a quantum mechanical property called degeneracy pressure makes the electrons resist compression, adding support to the core.

From Scientific American • Nov. 10, 2023

Hence, in the white dwarf stage of stellar evolution, it is the degeneracy pressure of the electrons, and not of the nuclei, that halts the collapse of the core.

From Textbooks • Oct. 13, 2016

As a result, in white dwarfs, the nuclei do not exhibit degeneracy pressure.

From Textbooks • Oct. 13, 2016

As the core is stabilized by degeneracy pressure, a last shudder of fusion passes through the outside of the star, consuming the little hydrogen still remaining.

From Textbooks • Oct. 13, 2016