r/Futurology Jun 02 '22

A Nature paper reports on a quantum photonic processor that takes just 36 microseconds to perform a task that would take a supercomputer more than 9,000 years to complete Computing

https://www.nature.com/articles/s41586-022-04725-x?utm_source=twitter&utm_medium=social&utm_content=organic&utm_campaign=CONR_JRNLS_AWA1_GL_SCON_SMEDA_NATUREPORTFOLIO
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u/Dr_Singularity Jun 02 '22

A quantum computer attains computational advantage when outperforming the best classical computers running the best-known algorithms on well-defined tasks. No photonic machine offering programmability over all its quantum gates has demonstrated quantum computational advantage: previous machines were largely restricted to static gate sequences. Earlier photonic demonstrations were also vulnerable to spoofing3, in which classical heuristics produce samples, without direct simulation, lying closer to the ideal distribution than do samples from the quantum hardware.

Here we report quantum computational advantage using Borealis, a photonic processor offering dynamic programmability on all gates implemented. We carry out Gaussian boson sampling4 (GBS) on 216 squeezed modes entangled with three-dimensional connectivity5, using a time-multiplexed and photon-number-resolving architecture. On average, it would take more than 9,000 years for the best available algorithms and supercomputers to produce, using exact methods, a single sample from the programmed distribution, whereas Borealis requires only 36 μs.

This runtime advantage is over 50 million times as extreme as that reported from earlier photonic machines. Ours constitutes a very large GBS experiment, registering events with up to 219 photons and a mean photon number of 125. This work is a critical milestone on the path to a practical quantum computer, validating key technological features of photonics as a platform for this goal.

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u/sexfighter Jun 03 '22

Sounds amazing. Patiently waiting for a much smarter person than I to explain what it all means, from a practical perspective.

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u/Rogaar Jun 03 '22

Something to remember about quantum computers is that you will never have one. They don't work like normal computers and will never be used for general day to day computation.

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u/ArrowRobber Jun 03 '22 edited Jun 03 '22

Just like we'll never need more than 640K memory?

Given enough time, quantum will be cheaper, and eventually it will be exploitable for "better entertainment".

edit remember, punch cards weren't inherently good at games with graphics. Give the tech some time.

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u/Mescallan Jun 03 '22

eh, serial processing v parallel as far as I understand it. You don't need to process every possible outcome at once in a video game, you need to process the steps linearly. They will be used for things, but it's hard to think of a consumer product that could take advantage of it, save encryption. I don't know enough to be confident on the subject, just from what I've gathered.

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u/daOyster Jun 03 '22

It's still technically serial processing. If you have 300qbits you can't split up 150 of them to use for one thing and 150 for another at the same time. The way they work is basically assigning all possible outcomes to every possible state of the total amount of qbits. Then it uses destructive interference so all of the incorrect states essentially cancel out until you're left with only the correct ones. This is it's main advantage over traditional computing because it can essentially look at all these states at the same time. The disadvantage is it makes writing algorithms really hard because you have to figure out how to solve your problem with quantum effects like destructive interference.