
Ask HN: Quantum Order of Operations - cwt
My primary goal is to gain a better understanding of why people study the quantum field.<p>I am interested in understanding how quantum process happen. My understanding at this point is that they are simultaneous (not sure if correct but its definitely next to nothing). My math background is decent (aka I will try to understand any answer you throw at me). Links, books, comments, and anything else you have to offer is welcome. Thanks
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ivan_ah
Not sure of what model you have in mind, but simultaneous doesn't seem
appropriate: there is definitely a notion of _sequence_ of operations.

For example, applying the X operator followed by the Y operator on a quantum
state |ѱ> can be written as:

    
    
        YX|ѱ>
    

(You don't need to know what X and Y are for the purpose of this example, but
think matrix multiplication, X "touching" the state before Y.)

RE books, this is a good one: [http://www.michaelnielsen.org/qcqi/QINFO-book-
nielsen-and-ch...](http://www.michaelnielsen.org/qcqi/QINFO-book-nielsen-and-
chuang-toc-and-chapter1-nov00.pdf)

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pjungwir
_Quantum Computing since Democritus_ by Scott Aaronson is excellent. If you
start reading his stuff you'll learn his mission in life is to teach people
that quantum doesn't mean simultaneous. :-)

