4 ms·

Xanadu's main thing is that they are really good at getting money from Canadian VCs and government. They often make insane claims like: https://arxiv.org/abs/18

Xanadu's main thing is that they are really good at getting money from Canadian VCs and government. They often make insane claims like: https://arxiv.org/abs/1810.10644 https://arxiv.org/abs/1810.10644 I'd take anything coming from them with a grain of salt.

ianai 4y ago
What about that is insane?
- latenightcoding 4y ago
  https://en.wikipedia.org/wiki/Boson_sampling https://en.wikipedia.org/wiki/Boson_sampling boson sampling was introduced for quantum supremacy experiments. it does not have any practical applications and it's supposed to be easy for QCs. Well the guys at Xanadu believe that for some bizarre reason it can be used to solve all sort of useful problems.
  - deepspace 4y ago
    Exactly. To use an analogy from simulation - as I understand it - one can do a very detailed finite element analysis of a component using hours of computing time to determine its failure mode -- or you can stress it until it breaks, and get your answer in a few seconds. That does not mean that breaking things is a good method to solve general problems; it is just very well suited for this specific problem.
    - krastanov 4y ago
      I do not think this is a good example. You and OP are making two orthogonal points (both of which are good, but not both apply to Bosonic Sampling). 1. You were making an argument about analog computers. There is big difference between a digital computer and an analog simulator. See this comics https://www.smbc-comics.com/comic/2013-07-19 https://www.smbc-comics.com/comic/2013-07-19 -- We have went through this with classical computers over the last 100 years. The first computers were analog simulators that were just rescaled physical experiments: instead of measuring the flow of a river you made a scale model; instead of measuring the trajectory of a bomb you made an analog electronic model. These computers were great time-savers, but they were single-purpose and not "scalable" (i.e. the precision of their results was very limited due to fundamental physical reasons). When digital computers become sophisticated enough, we stopped using analog computers: a digital fluid model of the river is better than an analog scale model because by "just" increasing the mesh resolution you get more precise results, infeasible in the analog case; the digital bomb trajectory simulator is better because by "just" adding a new term and changing a data type you get more realistic results. Basically, digital computers are (a) scalable and (b) reprogrammable. Analog computers are not -- they are just rescaled physical experiments. Much of quantum computation today is just that: an analog experiment too far from the digital regime. 2. The point that OP was making is that Boson sampling, while it can be considered "digital" and "programmable" is too "boring". It shows a computation that can not be done by a classical computer efficiently, but the computation itself is just some silly sampling problem from a probability distribution that we would probably never care about. However, to me at least, it is a very big deal that we can reprogram (change the parameters) on the fly the probability distribution. And it is an even bigger deal that this is a scalable computation: a simple analog computer just starts giving chaotic results when you add too many degrees of freedom, unlike here where you start sampling from even more complicated distributions.
ironSkillet 4y ago
If anything that paper looks really cool (not that I understand it). Transforming classical problems like graph isomorphism into a quantum algorithm is legit science and potentially extremely valuable.
- latenightcoding 4y ago
  Yeah their papers and github repos look cool alright. still pretty useless, read my other comment.
- bawolff 4y ago
  Did they actually find a quantum algorithm for graph isomorphism? I was under the impression that was a major unsolved problem and would be a pretty big deal. I have my doubts...
  - gilleain 4y ago
    It's now a _solved_ problem - both theoretically (with Babai et al's paper a few years ago) and practically (with nAUTy/Bliss, and similar software). Not sure what the key paper is, but "Graph isomorphism in quasipolynomial time" is at leas relevant: https://dl.acm.org/doi/10.1145/2897518.2897542 https://dl.acm.org/doi/10.1145/2897518.2897542 or perhaps, this arxiv paper: https://arxiv.org/abs/1512.03547 https://arxiv.org/abs/1512.03547 No idea about a quantum algorithm for GI
ttul 4y ago
I went camping with one of their software engineers. I think they are legit.
walrus01 4y ago
If the Canadian government suddenly grows some skepticism, they can just take the money and continue to shovel more funds at Telesat, which is now about 7 years behind schedule on its starlink-competitor LEO network.
- pkaye 4y ago
  How will Telesat launch their satellites?
  - walrus01 4y ago
    They seem to conveniently hand wave away that rather vital part.
  - itsoktocry 4y ago
    >How will Telesat launch their satellites? How does anyone launch satellites? You pay someone to do it. Are you under the impression you need to have a rocket company to do this? One of the mandates of SpaceX (and others) is to lower the cost of these things.

ianai 4y ago

What about that is insane?

latenightcoding 4y ago
https://en.wikipedia.org/wiki/Boson_sampling https://en.wikipedia.org/wiki/Boson_sampling boson sampling was introduced for quantum supremacy experiments. it does not have any practical applications and it's supposed to be easy for QCs. Well the guys at Xanadu believe that for some bizarre reason it can be used to solve all sort of useful problems.
- deepspace 4y ago
  Exactly. To use an analogy from simulation - as I understand it - one can do a very detailed finite element analysis of a component using hours of computing time to determine its failure mode -- or you can stress it until it breaks, and get your answer in a few seconds. That does not mean that breaking things is a good method to solve general problems; it is just very well suited for this specific problem.
  - krastanov 4y ago
    I do not think this is a good example. You and OP are making two orthogonal points (both of which are good, but not both apply to Bosonic Sampling). 1. You were making an argument about analog computers. There is big difference between a digital computer and an analog simulator. See this comics https://www.smbc-comics.com/comic/2013-07-19 https://www.smbc-comics.com/comic/2013-07-19 -- We have went through this with classical computers over the last 100 years. The first computers were analog simulators that were just rescaled physical experiments: instead of measuring the flow of a river you made a scale model; instead of measuring the trajectory of a bomb you made an analog electronic model. These computers were great time-savers, but they were single-purpose and not "scalable" (i.e. the precision of their results was very limited due to fundamental physical reasons). When digital computers become sophisticated enough, we stopped using analog computers: a digital fluid model of the river is better than an analog scale model because by "just" increasing the mesh resolution you get more precise results, infeasible in the analog case; the digital bomb trajectory simulator is better because by "just" adding a new term and changing a data type you get more realistic results. Basically, digital computers are (a) scalable and (b) reprogrammable. Analog computers are not -- they are just rescaled physical experiments. Much of quantum computation today is just that: an analog experiment too far from the digital regime. 2. The point that OP was making is that Boson sampling, while it can be considered "digital" and "programmable" is too "boring". It shows a computation that can not be done by a classical computer efficiently, but the computation itself is just some silly sampling problem from a probability distribution that we would probably never care about. However, to me at least, it is a very big deal that we can reprogram (change the parameters) on the fly the probability distribution. And it is an even bigger deal that this is a scalable computation: a simple analog computer just starts giving chaotic results when you add too many degrees of freedom, unlike here where you start sampling from even more complicated distributions.

ironSkillet 4y ago

If anything that paper looks really cool (not that I understand it). Transforming classical problems like graph isomorphism into a quantum algorithm is legit science and potentially extremely valuable.

latenightcoding 4y ago
Yeah their papers and github repos look cool alright. still pretty useless, read my other comment.
bawolff 4y ago
Did they actually find a quantum algorithm for graph isomorphism? I was under the impression that was a major unsolved problem and would be a pretty big deal. I have my doubts...
- gilleain 4y ago
  It's now a _solved_ problem - both theoretically (with Babai et al's paper a few years ago) and practically (with nAUTy/Bliss, and similar software). Not sure what the key paper is, but "Graph isomorphism in quasipolynomial time" is at leas relevant: https://dl.acm.org/doi/10.1145/2897518.2897542 https://dl.acm.org/doi/10.1145/2897518.2897542 or perhaps, this arxiv paper: https://arxiv.org/abs/1512.03547 https://arxiv.org/abs/1512.03547 No idea about a quantum algorithm for GI

ttul 4y ago

I went camping with one of their software engineers. I think they are legit.

walrus01 4y ago

If the Canadian government suddenly grows some skepticism, they can just take the money and continue to shovel more funds at Telesat, which is now about 7 years behind schedule on its starlink-competitor LEO network.

pkaye 4y ago
How will Telesat launch their satellites?
- walrus01 4y ago
  They seem to conveniently hand wave away that rather vital part.
- itsoktocry 4y ago
  >How will Telesat launch their satellites? How does anyone launch satellites? You pay someone to do it. Are you under the impression you need to have a rocket company to do this? One of the mandates of SpaceX (and others) is to lower the cost of these things.