Dirac notation is very expressive: not only does it allow to write quantum states and operations more concisely, it can also be used to shorten written English words and phrases! Here are some examples:

Dirac notation puzzle

What is shown on the hidden photo?

  • 3
    $\begingroup$ My friend and I created this puzzle for a Christmas-themed mini-escape-room, in which you had to help Santa escape from a quantum lab. Enjoy! $\endgroup$ Mar 6, 2021 at 18:29
  • $\begingroup$ Can you change image hosting, please? There are problems with accessing imgur.com in my country. $\endgroup$ Mar 8, 2021 at 17:18
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    $\begingroup$ I'm sorry about that, but i.stack.imgur.com is how Stack Exchange images should be hosted; converting the images would make the question less self-contained which is the opposite of what we would want. $\endgroup$
    – bobble
    Mar 8, 2021 at 17:23

1 Answer 1


The answer is

Silver Tinsel


treating <Ψ| as "BRA" and |Ψ> as "KET" (their names from Dirac notation, as they form the begining and ending "BRAcKET")

We get

coBRA basKET
BRAclet trinKET
celeBRAtion rocKET
viBRAnt marKET
BRAin locKET
zeBRA sKETch

Taking the

letters from the numbered blanks from the pictures


the Christmassy SILVER TINSEL

  • $\begingroup$ "Shorten", as in rot13(ercynpr guerr yrggref jvgu guerr flzobyf? Abg rknpgyl fubegre...) $\endgroup$ Mar 8, 2021 at 14:56

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