
We’d have more quantum computers if it weren’t so hard to find the damn cables - respinal
https://www.technologyreview.com/s/612760/quantum-computers-component-shortage/
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stwe_
I am working with one of these dilution refrigerators of Oxford Instruments in
my PhD thesis (not directly quantum computing, but a related topic in the
direction of quantum computing). They are an incredible piece of machinery,
with the push of a button they cool down your sample from room temperature to
about 20 mK (admittedly, it takes ~30 Hours). That's 0.002 degrees above
absolute zero.

I wonder how much of the 500k$ is really the material cost. As it was said in
the article, the Helium-3 gas is already 40k$. And there is a lot of high-
purity metals used: gold-plated oxygen-free copper for the main parts, silver
wire for thermal anchoring and heat exchangers, indium wire for vacuum seals
etc.

And thats just for the cryostat. To really use the cryostat for quantum
computing experiments, you need to buy all of the cryogenic high-frequency
electronic stuff. The cryogenic cables mentioned in the article by Coax, Ltd.
are indeed really really expensive. Our last batch of NbTi-NbTi cables (i.e.
superconducting inner + outer conductor) were about 1500$ per meter. Cryogenic
microwave amplifiers (they operate at ~3.5 K to reduce microwave noise) cost
about 5000$ per piece. Microwave circulators run at about 1500$ per piece.
(According to the google paper, they used 9 cryogenic amps and 45 cryogenic
circulators).

It's really very fascinating. But on the other side, I guess there is just not
enough demand to justify founding another company building these fridges or
superconducting cables. Unless of course at some point you manage to build
these systems in large scale. But right now, that is just not feasible because
it's no plug-and-play system. You have to constantly adjust and recalibrate
the electronics to make the chip work.

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madengr
The article talks about superconducting cables, but these cryogenic cables are
not superconducting. Seem like regular Kapton flex cables, either strip line
or broadside coupled.

[https://www.delft-circuits.com/wp-
content/uploads/2019/08/Da...](https://www.delft-circuits.com/wp-
content/uploads/2019/08/Datasheet-CrioFlex-CF2.pdf)

I suppose you could use superconducting ribbon, or sputter thin film
superconductor onto a Kapton core.

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anonytrary
Misleading title; also the article is mostly fluff. TLDR; quantum computers
are expensive because superconductors are expensive to maintain, and companies
like IonQ and Delft Circuits are looking into some solutions.

~~~
fsh
IonQ uses trapped ions, not superconducting circuits. Completely different
technology.

~~~
anonytrary
That's still a potential solution.

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yskchu
[https://archive.is/YVWm8](https://archive.is/YVWm8)

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p1mrx
I usually try Monoprice, or eBay.

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smabie
Don’t go for the monster quantum cables, they are usually a rip-off!

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dvh
You mean more than zero?

~~~
AlEinstein
Are you saying that you personally have zero quantum computers or that nobody
has more than zero quantum computers?

~~~
MisterTea
You can't tell if someone has a quantum computer until you observe it.

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unnouinceput
Quote: "The problem is that these huge cylinders, which can cost between
$500,000 and $1 million each, are custom-made, and researchers say that only a
few companies, like BlueFors in Finland and Oxford Instruments in the UK, are
producing high-quality ones."

There, the next unicorn - why only UK & Finland and not a Silicon Valley
start-up as well? In the end it's just tech that requires investment, and God
help us, there are plenty of venture capitalists looking for next unicorn. I
mean the quantum computing field is so hot these days that everyday you find a
new article about it.

~~~
imglorp
I'm a little unclear on the benefit here. Say I have a hard problem and want
to spend say $15 million for one machine, and further say that my problem
might be suitable for a quantum algorithm, and further say I'm okay restocking
all the exotic cryogenics etc.

At that price, I could buy at least 15,000 boring old machines using a boring
distributed algorithm.

Is that quantum algorithm really worth it?

~~~
yjftsjthsd-h
I assume the idea is that the technology is still in its infancy and in a few
years it will be competitive.

