Black holes: from event horizons to trapping horizons - LUTH ...
Black holes: from event horizons to trapping horizons - LUTH ...
Black holes: from event horizons to trapping horizons - LUTH ...
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Angular momentum and area evolution laws<br />
Area evolution law for an <strong>event</strong> horizon<br />
A(t) : area of the 2-surface St; S ɛ : volume element of St; ¯κ(t) := 1<br />
<br />
κ<br />
A(t) St<br />
S ɛ<br />
Integrating the null Raychaudhuri equation on St, one gets<br />
d2 <br />
A<br />
− ¯κdA = −<br />
dt2 dt<br />
<br />
8πT (ℓ, ℓ) + σ (ℓ) :σ (ℓ) − (θ(ℓ) ) 2<br />
2 + (¯κ − κ)θ(ℓ) S<br />
ɛ (1)<br />
St<br />
[Damour, 1979]<br />
Eric Gourgoulhon (<strong>LUTH</strong>) <strong>Black</strong> <strong>holes</strong>: <strong>trapping</strong> <strong>horizons</strong> CERN, 17 March 2010 34 / 38