ρ ( a )
a ( t )
H ( t )
1 / ( a H )
w ≡ p / ρ
Λ
constant
eHt
a − 1
−1
Radiation
a − 4
t1/2
1/(2t)
a
1/3
Matter
a − 3
t2/3
2/(3t)
a 1 / 2
0