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Comment by laurentoget | Hacker News Reader

"Problem is, a lot of CEOs in industry and the financial sector can’t tell a bra from a ket"

i do not know enough about quantum computing to judge whether this article is accurate or not, but it certainly is well written and entertaining

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I highly recommend "Quantum computing for the very curious"[0] for an introduction to quantum mechanics. I went through it years ago and can still remember the main ideas thanks to the built-in spaced repetition.

[0] https://quantum.country

It is remarkable how everybody only seems to comment on "spaced repetition" rather than anything involving quantum computing when they discuss that site.

Regardless, memorizing a few facts won't help with reasoning about "is quantum computing even possible".

Maybe because it's pretty much the only essay that offers built-in spaced repetition?

I'm familiar with bras I think... what is a "ket"?

https://en.wikipedia.org/wiki/Bra%E2%80%93ket_notation

a ket is |v>

It seems I was NOT familiar with what a bra is...

It's the hermitian conjugate of the corresponding ket.

And a monad is an endofunctor of a monoid

With that at least I can be nearly certain we are not discussing an alternative brassiere.

It's physicist notation for inner products: https://en.wikipedia.org/wiki/Bra%E2%80%93ket_notation

I agree that many in the financial sector do not know much about quantum computing, but it also does not seem that some in the quantum that do not understand the details of the problems that the financial sector has either. For instance, those in the capital markets/trading floors in Europe and North America do significant risk calculations with hundreds or a thousand variables on up to 100,000 positions with a certain confidence. Many of these risk calculations need to be reported nightly to regulators. These financial companies are paying many millions per year to AWS, Azure, or Google to do these calculations on classical computers. However, many parts of these calculations could be done with quantum computers relatively instantly, given enough qubits. I realize that the technology and reliability is not there today, but hopefully it will come soon. I would not be surprised if by 2035 using quantum computers to do many variable risk calculations would become (almost) mandatory for major European and North American financial companies.

What makes you say this? Which particular quantum algorithm do you think gives an exponential speedup for multi-variate risk predictions? And why do you think there is any chance in hell that a quantum computer would exist by 2035 that could even store an input of the size you're talking about, nevermind have spare qubits to actually process it?

On a semi-related note, bra-kets are just magical. Programmers who deride mathematical notations, and claim we should abolish equations in favor of pseudocode, should try to get a glimpse of their power.

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