作者anticigo (水饺)
看板Physics
标题[题目] 两个问题
时间Wed Sep 16 10:24:14 2009
[领域] 量子力学,狭义相对论 (题目相关领域)
[来源] 期中考试的一些题目 (课本习题、考古题、参考书...)
[题目]
1.(Lorentz Transformation)
Lorentz transformation in the x-direction can be capturde by a 2x2 matrix
[ γ -γu ]
[-γu γ ]
where γ=1/√((1-u)^2) and u is the relative velocity between two inertia
frames. For simplicity, I have set the speed of light to be unity c=1. For a
particle moving at velocity v in the (x,t) frame, find its corresponding
velocity v' in the (x',t')frame by the reduced Lorentz matrix in above.
2.(Relativistic Electrons)
The kinetic energy of a relativistic electron is described by the 4x4 matrix
k= [ mI σ‧P ]
[σ‧P mI ]
where I is the identity matrix of dimension two and the Pauli matrices σ are
σx=[ 0 1 ] σy=[ 0 -i ] σz=[ 1 0 ]
[ 1 0 ] [ i 0 ] [ 0 -1 ]
The rest mass of motion of the electron is m and its momentum in P=(px,py,pz).
(a)Bring the kinetic matrix k to diagonal form and find out the corresponding
energies.
(b)Choose the coordinate system so that the electron is moving along the
positive z-axis. Find all eigenstates for a relativistic electron in motion.
[瓶颈] (写写自己的想法,方便大家为你解答)
1.我不知道如何下手啊= =+
2.我虽然已经算出来这个矩阵对角化的形式,但是不知道後面到底在讲些什麽...
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1F:推 abc2090614:把v写成4-velocity, say V 然後用V=lambda(-v)V' 作 09/16 14:13
2F:→ abc2090614:lambda就是lorentz tran matrix 09/16 14:13
3F:→ abc2090614:打错了 lambda(-u)才对 09/16 14:14