Live data from Hacker News

An important quantum algorithm may be a property of nature

technologyreview.com

1–10 of 80 posts

Re: An important quantum algorithm may be a property of nature

#2
This is a bit of a tangent (that the author takes): “But during protein assembly, each amino acid must be chosen from a soup of 20 different options. Grover’s algorithm explains these numbers: a three-step quantum search can find an object in a database containing up to 20 kinds of entry. Again, 20 is the optimal number.”

20 is the number of amino acids, but this is ignoring stop codons (and specialized amino acids used for initiation).

It’s not super clear to me at what level of abstraction the search is taking place - it can’t be the tRNA space because that’s not just 20 options.

The point that electrons seem to follow a Grover search is cool. I’m just unclear on whether the biological part holds up.

Re: An important quantum algorithm may be a property of nature

#4
A reason why I allow myself some skepticism on the feasibility of quantum computing is that if it were possible, I would have expected evolution to have used it somehow.

If it turns out that protein folding really use a quantum computation, I'll move quantum computers from the "too good to be true" category to the "probably revolutionary stuff that I will see in my lifetime" alongside with nuclear fusion and strong AI.

Re: An important quantum algorithm may be a property of nature

#5
post #4

A reason why I allow myself some skepticism on the feasibility of quantum computing is that if it were possible, I would have expected evolution to have used it somehow. If it turns out that protein folding really use a quantum computation, I'll move quantum computers from the "too good to be true" category to the "probably revolutionary stuff that I will see in my lifetime" alongside with nuclear fusion and strong A…

> if it were possible, I would have expected evolution to have used it somehow.

That seems reasonable as long as you're consistent in applying the same skepticism to other inventions, such as the internal combustion engine and the wheel.

Re: An important quantum algorithm may be a property of nature

#6
Hmm, there are several things I find strange about this article.

There are 22 proteinogenic amino acids (admittedly two are rare, selenocysteine and pyrrolysine, but with rarity comes importance when they do occur).

The search for the correct amino acid is not class balanced, e.g. the aromatics are much less common.

The tRNAs are also not equally distributed, neither in the codon-anticodon pairing, the aromatics are coded for by only one or two, I suppose this is somewhat reflected in the frequency (see above).

Even within one amino acids possible tRNA the ratio's are species dependant to a remarkable degree (see codon optimisation in genetic engineering. You can also tell by sequence analysis if horizontal transfer has occurred if the frequencies are all wrong) and is used to regulate synthesis. e.g. if a species has tRNA UUU : tRNA UUC of 3 : 1 then (classically) one would expect a protein incorporating phenylalanine as UUC to take 3 times longer than UUU to incorporate.

Re: An important quantum algorithm may be a property of nature

#7
post #4

A reason why I allow myself some skepticism on the feasibility of quantum computing is that if it were possible, I would have expected evolution to have used it somehow. If it turns out that protein folding really use a quantum computation, I'll move quantum computers from the "too good to be true" category to the "probably revolutionary stuff that I will see in my lifetime" alongside with nuclear fusion and strong A…

Your argument doesn't stand up to cursory examination. There are all sorts of tricks of physics that evolution never found out how to use. Natural systems don't use the (macroscopic) wheel either, but that works great. Refrigeration works great, but nature doesn't use that either. Complex life has barely been around 540 million years ago. Why would you suppose evolution would have had time to explore the entire space of techniques that physics allows?

Re: An important quantum algorithm may be a property of nature

#8
post #4

A reason why I allow myself some skepticism on the feasibility of quantum computing is that if it were possible, I would have expected evolution to have used it somehow. If it turns out that protein folding really use a quantum computation, I'll move quantum computers from the "too good to be true" category to the "probably revolutionary stuff that I will see in my lifetime" alongside with nuclear fusion and strong A…

Your argument doesn't stand up to cursory examination. There are all sorts of tricks of physics that evolution never found out how to use. Natural systems don't use the (macroscopic) wheel either, but that works great. Refrigeration works great, but nature doesn't use that either. Complex life has barely been around 540 million years ago. Why would you suppose evolution would have had time to explore the entire space…

Actually, rolling things, from seeds to eggs, including whole shrimps is a locomotion technique used by nature since a long time. The axle is something it does not use, and I would argue does not need. In all natural terrains, legs are a superior option.

The physical principles behind refrigeration are witnessed in several places in nature.

Re: An important quantum algorithm may be a property of nature

#9
post #5
post #4

A reason why I allow myself some skepticism on the feasibility of quantum computing is that if it were possible, I would have expected evolution to have used it somehow. If it turns out that protein folding really use a quantum computation, I'll move quantum computers from the "too good to be true" category to the "probably revolutionary stuff that I will see in my lifetime" alongside with nuclear fusion and strong A…

> if it were possible, I would have expected evolution to have used it somehow. That seems reasonable as long as you're consistent in applying the same skepticism to other inventions, such as the internal combustion engine and the wheel.

The physical principles behind combustion engines and the wheel are displayed in many life forms. Their engineering constraints and goals differ.

It is, however, reasonable to expect evolution to find a way to exploit quantum algorithms as it is very useful to several fitness advantages and is something that you would expect to be achievable through protein manipulations.

Re: An important quantum algorithm may be a property of nature

#10
post #5
post #4

A reason why I allow myself some skepticism on the feasibility of quantum computing is that if it were possible, I would have expected evolution to have used it somehow. If it turns out that protein folding really use a quantum computation, I'll move quantum computers from the "too good to be true" category to the "probably revolutionary stuff that I will see in my lifetime" alongside with nuclear fusion and strong A…

> if it were possible, I would have expected evolution to have used it somehow. That seems reasonable as long as you're consistent in applying the same skepticism to other inventions, such as the internal combustion engine and the wheel.

Bacterial flagella are rotary, so very close to being wheels.
Post reply on HN