||
创建时空可变系多线矢物理学(83)相应推广的运动方程
(接(82))
设在L积分边界上,[矢A(X,n)],[矢B(X,n)],各分量模长的变分为零,
按变分法有:
变分L=[偏L/偏A(X,n)(x)]变分A(X,n)(x)
+[偏L/偏(W(A(X,n)(x))A(X,n)(x)时间导数)]
变分(W(A(X,n)(x))A(X,n)(x)时间导数)
+[偏L/偏B(X,n)(x)]变分B(X,n)(x)
+[偏L/偏(W(B(X,n)(x))B(X,n)(x))时间导数]
变分(W(B(X,n)(x))B(X,n)(x)时间导数)
=变分A(X,n)(x)([偏L/偏A(X,n)(x)]
-(d/dt(X))[偏L/偏(W(A(X,n)(x))A(X,n)(x)时间导数)])
+变分B(X,n)(x)([偏L/偏B(X,n)(x)]
-(d/dt(X))[偏L/偏(W(B(X,n)(x))B(X,n)(x)时间导数)])=0,
变分H=[偏H/偏A(X,n)(x)]变分A(X,n)(x)
+[偏H/偏(W(A(X,n)(x))A(X,n)(x)时间导数)]
变分(W(A(X,n)(x))A(X,n)(x)时间导数)
+[偏H/偏B(X,n)(x)]变分B(X,n)(x)
+[偏H/偏(W(B(X,n)(x))B(X,n)(x))时间导数]
变分(W(B(X,n)(x))B(X,n)(x)时间导数)
=变分A(X,n)(x)([偏L/偏A(X,n)(x)]
+(d/dt(X))[偏L/偏(W(A(X,n)(x))A(X,n)(x)时间导数)])
+变分B(X,n)(x)([偏L/偏B(X,n)(x)]
+(d/dt(X))[偏L/偏(W(B(X,n)(x))B(X,n)(x)时间导数)])=0,
分别以前式代入后式,对于任意的变分A(X,n)(x), 变分B(X,n)(x),分别得到其相应推广的运动方程:
[偏L/偏A(X,n)(x)]-(d/dt(X))[偏L/偏(W(A(X,n)(x))A(X,n)(x)时间导数)]=0,
[偏L/偏B(X,n)(x)]-(d/dt(X))[偏L/偏(W(B(X,n)(x))B(X,n)(x)时间导数)]=0,
[偏H/偏A(X,n)(x)]+(d/dt(X))[偏H/偏(W(A(X,n)(x))A(X,n)(x)时间导数)]=0,
[偏H/偏B(X,n)(x)]+(d/dt(X))[偏H/偏(W(B(X,n)(x))B(X,n)(x)时间导数)]=0,
(未完待续)
Archiver|手机版|科学网 ( 京ICP备07017567号-12 )
GMT+8, 2024-6-30 22:22
Powered by ScienceNet.cn
Copyright © 2007- 中国科学报社