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While breathless press announces are indeed often too hyped, I think we should keep in mind the history of the transistor. We went from fragile expensive single

by ArnoVW 5y ago

While breathless press announces are indeed often too hyped, I think we should keep in mind the history of the transistor. We went from fragile expensive single transistors to VLSI in half a century. And we consider that amazing. That doesn't mean the same thing will happen with QC, it just means that maybe we should QC some slack, and keep cheering for the incremental improvements that arrive every couple of years? https://en.wikipedia.org/wiki/History_of_the_transistor https://en.wikipedia.org/wiki/History_of_the_transistor

sgt101 5y ago
Yup - agree, and also "genetics tech" 70 years from Crick and Watson to mRNA vaccines and then actual genetic engineering in adults with CRISPR [1]. This kind of progress is amazing, I think we should start the clock on QC from either Shor's paper or maybe from the first 2 bit QC in 1998 - so that takes us to say 2060? [1] https://www.nature.com/articles/d41586-021-01776-4 https://www.nature.com/articles/d41586-021-01776-4
grungegun 5y ago
There's one big issue with QC currently. There is no mathematical demonstration that QC is scalable. All the speed-ups need some form of error correction to scale the way digital computation has. All hardware advances are just increases in computational fidelity so far to allow more useful qubits. Shor has an error correction algorithm for a single qubit, and there have been improvements to that, but nothing general enough to show that QC can even scale like digital computers can.
- throw149102 5y ago
  From my understanding, the quantum threshold theorem states that if you have a low base error rate (1-3%) you can apply multiple levels of a single quantum error correcting code to get arbitrarily low levels of errors on a logical qubit ("remove errors faster than you introduce them"). Right now that means that you need approximately 1000x physical qubits for 1 logical qubit, but to me that's a solid mathematical/theoretical demonstration that you can scale QC.
  - grungegun 5y ago
    You're right. I've looked at quantum codes before, but apparently my understanding was lacking - thanks for the info.

by ArnoVW 5y ago

sgt101 5y ago

Yup - agree, and also "genetics tech" 70 years from Crick and Watson to mRNA vaccines and then actual genetic engineering in adults with CRISPR [1]. This kind of progress is amazing, I think we should start the clock on QC from either Shor's paper or maybe from the first 2 bit QC in 1998 - so that takes us to say 2060? [1] https://www.nature.com/articles/d41586-021-01776-4 https://www.nature.com/articles/d41586-021-01776-4

grungegun 5y ago

There's one big issue with QC currently. There is no mathematical demonstration that QC is scalable. All the speed-ups need some form of error correction to scale the way digital computation has. All hardware advances are just increases in computational fidelity so far to allow more useful qubits. Shor has an error correction algorithm for a single qubit, and there have been improvements to that, but nothing general enough to show that QC can even scale like digital computers can.

throw149102 5y ago
From my understanding, the quantum threshold theorem states that if you have a low base error rate (1-3%) you can apply multiple levels of a single quantum error correcting code to get arbitrarily low levels of errors on a logical qubit ("remove errors faster than you introduce them"). Right now that means that you need approximately 1000x physical qubits for 1 logical qubit, but to me that's a solid mathematical/theoretical demonstration that you can scale QC.
- grungegun 5y ago
  You're right. I've looked at quantum codes before, but apparently my understanding was lacking - thanks for the info.