An epic haiku


This is an epic haiku composed by Kevin Brake as a study aid for a quantum mechanics subject. Suprisingly he passed the subject.

Quantum Mechanics

Write quantum haikus
To make the concepts easy
To be remembered

Ket describes some state
Bra represents the same state
Complex conjugates

A ket by constant
Still describes the same state as
Just the ket alone

A bra by a ket
Gives the part of bra in ket
A complex number

This combination
A ket with some other bra
Is called a bra

A ket can be thought
Of just like a row vector
Maybe very long

A bra it may be
Concieved as merely being
A column vector

An operator
Can change the state described
Whenever you want

The eigenstates of
An operator do not
Change when it does act

Except a slight change
A constant before the ket
the eigenvalue

From now I'll write
An arbitary oper-
ator as A^

A ket that's called |a>
Is the arbitary ket
That I will now use

|a>'s an eigenstate
Of A^ and A^|a>
Will give you A|a>

Sum brackets of all
the eigenstates of A^
And you will get one

And now for A^
And all it's properties
This will take a while

Represent A^
By a matrix if you wish
Elements complex

Just like matrix math
Operators don't commute
Unlike plain numbers

The commutator
A^B^ less B^A^
It is important

The expectation
Value is <a|B^|a>
For all of the |a>s





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