
Quantum Computing in the NISQ era and beyond [pdf] - mathgenius
https://quantum-journal.org/papers/q-2018-08-06-79/
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mathgenius
I really like this description of entanglement:

"To understand the concept of entanglement, imagine a system with many parts,
for example a book which is 100 pages long. For an ordinary classical 100-page
book, every time you read another page you learn another 1% of the content of
the book, and after you have read all of the pages one by one you know
everything that’s in the book. But now suppose instead that it’s a quantum
book, where the pages are very highly entangled with one another. Then when
you look at the pages one at a time you see only random gibberish, and after
you have read all the pages one by one you know very little about the content
of the book. That’s because the information in the quantum book is not
imprinted on the individual pages; it is encoded almost entirely in how the
pages are correlated with one another. If you want to read the book you have
to make a collective observation on many pages at once. That’s quantum
entanglement, the essential feature making information carried by quantum
systems very different from information processed by ordinary digital
computers."

