Cold electron degeneracy pressure
For an ideal spin-½ electron gas with k_BT much smaller than its kinetic Fermi energy, occupied momentum states extend to p_F=ℏ(3π²nₑ)¹ᐟ³.
Key knowledge
For an ideal spin-½ electron gas with k_BT much smaller than its kinetic Fermi energy, occupied momentum states extend to p_F=ℏ(3π²nₑ)¹ᐟ³. The nonrelativistic limit has P=ℏ²(3π²)²ᐟ³nₑ⁵ᐟ³/(5mₑ); the ultrarelativistic limit has P=ℏc(3π²)¹ᐟ³nₑ⁴ᐟ³/4. These leading pressures are temperature-independent.
Values and equations
p_F=ℏ(3π²nₑ)¹ᐟ³; P_NR=ℏ²(3π²)²ᐟ³nₑ⁵ᐟ³/(5mₑ); P_UR=ℏc(3π²)¹ᐟ³nₑ⁴ᐟ³/4
- p_F
- electron Fermi momentum kg m s⁻¹
- nₑ
- electron number density m⁻³
- ℏ
- reduced Planck constant J s
- mₑ
- electron rest mass kg
- P_NR,P_UR
- cold nonrelativistic and ultrarelativistic pressure limits Pa
- c
- vacuum light speed m s⁻¹
Conditions and scope
- Use p_F≪mₑc or p_F≫mₑc for the corresponding limit, ideal isotropic electrons, and negligible thermal/nonideal corrections.
- Electron number density and total stellar mass density differ: composition determines nₑ. These formulas alone do not determine a neutron-star equation of state or an exact white-dwarf limiting mass.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read the spin multiplicity, number-density and pressure integrals and both limits. Re-expressed h as2πℏ and checked coefficients. Excluded the notes' Pauli-as-force wording, wrong-sign thermal wavelength criterion and μₑ=1/2 ionized-medium assertion.
2026-10-10 · Independent AI editorial review: All44 exact root-authored compact records, equations/variable units/conditions and140 origin edges accepted after independently reading final6/18 with bounded primary bodies and matching prior38/122 scientific fingerprints unchanged. Exact claim/edge review is distinct from combined inventory scope and separate CLE26 approval; no entire cited books or old-corpus experimental revalidation is asserted. Receipt: cosmos-completion-independent-content-and-inventory-review.1.
Entry details
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- uni-cosmos-degenerate-electron-pressure
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- Structured reference record
- University core expansion