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I'm not sure about the next 20 years, but quantum computers are really good at running calculations in parallel and finding a result. I'm not 100% sure I'm accu

I'm not sure about the next 20 years, but quantum computers are really good at running calculations in parallel and finding a result. I'm not 100% sure I'm accurate, but I believe if an algorithm is a good candidate to run on, say, a Spark cluster, a quantum computer would be much better at it. I think the biggest change will be that quantum computing can really kill at machine learning, upping the numbers of nodes in neural networks with an exponential relationship to the number of qubits. It might turn neural nets into a neat toy that Facebook uses to show us sort-of good ad predictions to something that really cuts into a wide range of things that only humans are capable of doing.

lacker 7y ago
Quantum computers are not generically good at all parallel problems. They have better asymptotic runtime for “brute force search” type problems, where you know there is some answer but you have to guess-and-check repeatedly. Roughly they change a 2^n brute force algorithm to a 2^(n/2) algorithm in that case. The main area these problems are important is cryptography.
- asdfman123 7y ago
  So what you're saying is I should short sell Bitcoin?
  - insulanus 7y ago
    You can read more about this issue here: https://en.bitcoin.it/wiki/Quantum_computing_and_Bitcoin https://en.bitcoin.it/wiki/Quantum_computing_and_Bitcoin
    - henryw 7y ago
      The article says "Attacking Bitcoin keys would require around 1500 qubits". So with 28 of these, Bitcoin is compromised?
      - whaddawhat 7y ago
        No, you need 1500 coherent qubits, in a single system.
- krzat 7y ago
  Would it be possible to evalute n randomly generated neural nets to find the best one?
  - Arelius 7y ago
    Maybe in theory, but you'd at least have to fit the entire neural net into the width of the computer. So we'd need a maching with millions of qubits? That's a bit hard to fathom.
- deleted 7y ago
  [deleted]
tempay 7y ago
> if an algorithm is a good candidate to run on, say, a Spark cluster, a quantum computer would be much better at it. This is not true. Some parallelizable tasks will benefit from massive speed ups but most won't.

lacker 7y ago

Quantum computers are not generically good at all parallel problems. They have better asymptotic runtime for “brute force search” type problems, where you know there is some answer but you have to guess-and-check repeatedly. Roughly they change a 2^n brute force algorithm to a 2^(n/2) algorithm in that case. The main area these problems are important is cryptography.

asdfman123 7y ago
So what you're saying is I should short sell Bitcoin?
- insulanus 7y ago
  You can read more about this issue here: https://en.bitcoin.it/wiki/Quantum_computing_and_Bitcoin https://en.bitcoin.it/wiki/Quantum_computing_and_Bitcoin
  - henryw 7y ago
    The article says "Attacking Bitcoin keys would require around 1500 qubits". So with 28 of these, Bitcoin is compromised?
    - whaddawhat 7y ago
      No, you need 1500 coherent qubits, in a single system.
krzat 7y ago
Would it be possible to evalute n randomly generated neural nets to find the best one?
- Arelius 7y ago
  Maybe in theory, but you'd at least have to fit the entire neural net into the width of the computer. So we'd need a maching with millions of qubits? That's a bit hard to fathom.
deleted 7y ago
[deleted]

tempay 7y ago

> if an algorithm is a good candidate to run on, say, a Spark cluster, a quantum computer would be much better at it. This is not true. Some parallelizable tasks will benefit from massive speed ups but most won't.