The
lF
4
and sine-Gordon
Field Equation
•
The simplest examples are:
•
J =
lF
4
which leads to the cubic KG equation:
•
¶
m
¶
m
F
+ m
2
F
+
lF
3
= 0
•
And
J
sG
= (sin
lF
) m
2
/
l
-m
2
F
•
which leads to the sine-Gordon equation:
•
@
¹
@
¹
©
+
m
2
¸
s
i
n
¸
©
=
0
When
l
approaches
zero they both reduce to the
usual
linear KG equation:
¶
m
¶
m
+m
2
f
=0