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Comment by jdjdjdhhd | Hacker News Reader

They are overvalued until you understand how to use them

“There are lots of great crypto projects, just look for the builders!”

Sorry, I’m not convinced. Over a decade of media puffery about how quantum computing will break encryption and nothing to indicate this is actually a claim based in reality.

We know quantum algorithms can break some forms of asymmetric encryption. The only issue is the practical problem of engineering a quantum computer with enough qubits to run them.

Now, it may be very, very hard to do this, and it may take decades more, or it may never be realised. Or a breakthrough may happen next year. There are no theoretical reasons it is impossible.

From a cryptography perspective, it takes a long time to create new cryptographic algorithms and gain trust in them. Many years of cryptanalysis are required by many people. So we are gradually moving towards quantum safe versions of asymmetric crypto. This is the only prudent thing to do.

In what sense do you feel that there is a claim not based in reality?

> The only issue is the practical problem of engineering a quantum computer with enough qubits to run them.

> In what sense do you feel that there is a claim not based in reality?

“Should be theoretically possible” - I’ll believe it when I see it. Anything quantum is always littered with qualifiers that “this isn’t possible now but the math checks out!” and hand waves potential issues.

Every few years I do a deep dive to learn that nothing has really changed, and the machines still have some fundamental limitation that nobody has solved for how to scale them to a useful # qubits.

I'd argue that a lot is changing, but it's a hard thing to do. We have processors with hundreds of (noisy) qubits. We have error correction schemes (that are not realisable yet though). We're exploring multiple different approaches to qubits, from superconducting ones to topological qubits.

I don't think I've seen any hand waving of potential issues by anyone. Everyone acknowledges it is hard.

Is your complaint simply that it's taking a long time? Or can you point me to some of the "hand waving" claims you refer to?

Are these systems delicate? Is this a higher form of "solid state device" Are they simple to manufacture.

I'm curious about them but I'm skeptical on their usefulness compared to existing things that can actual be observed with the naked eye. I'm a big fan of trouble shooting with an ohm meter and I could apply the same to a techniques to a visible light optical circuit.

What tools are used to trouble shoots a qubit?

"I'm skeptical on their usefulness compared to existing things that can actual be observed with the naked eye. I'm a big fan of trouble shooting with an ohm meter and I could apply the same to a techniques to a visible light optical circuit."

What you are measuring with an ohm meter is not visible to the naked eye. Electricity is not visible to the naked eye. Neither is heat. Neither are x-rays. Neither is math. Their effects might be, but they themselves aren't.

It's easy to come up with more examples of things not visible to the naked eye which are very useful.

The ohm meter is visible and it is one of many ways of detecting electron flow. I was trying to ask how the qubits are observed.

Observing the phenomena whether directly or indirectly we built a sophisticated society. I want to know how hard it is to observe a qubit. The directness is what I want.

What indirect effects of a qubit can one observe with the naked eye?

Some qubits are Doppler cooled, causing it to fluoresce. In these case you can observe the emitted light using a special camera. Check this out: https://petapixel.com/2018/02/12/picture-single-atom-wins-sc...

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