A new theoretical model suggests quantum entanglement helps hold DNA together | Hacker News Reader

A new theoretical model suggests quantum entanglement helps hold DNA together

technologyreview.com

68 pointsjonbaer34 comments

I recently finished my PhD on quantum effects in biology (my focus was on photosynthesis). This article and the many others like it are full of poorly substantiated hype.

Yes, quantum mechanics is important to some biological processes. But (1) many physicists in this field have blatantly ignored vital chemical and biological details when constructing their models and (2) it's not entirely clear who should be "surprised" by this sort of quantum entanglement, which is not that different from standard notions of chemical bonds.

Also note that this news piece is actually from 2010, and the preprint article it refers to (http://arxiv.org/abs/1006.4053) was never published in a peer-reviewed journal -- presumably because the authors couldn't get it past peer review.

> Yes, quantum mechanics is important to some biological processes.

I'm not quite sure how to parse this statement. Wouldn't quantum mechanics underlie all biological processes?

The point is that, while quantum rules sit at the bottom of most macroscopic objects, quantum rules aren't important for most objects on an everyday basis. Similarly, if entanglement is important for explaining the behavior of DNA, that would be novel factual information.

Yes, exactly. You don't need to understand quantum mechanics to understand most biological processes (within the limits of our current knowledge). Biologists don't need to learn quantum mechanics.

that is not true at all. I'm engineering a better hydrogenase and had to explain marcus theory to the biology profs (i.e. all of them, since I work at a biology institute). Totally hopeless, because they didn't know quantum. Knowing quantum from chemistry, I taught the basic principles to myself in a few minutes.

He said most. Look at what the Anton CPU can do with just force fields and spring modeled bonds. They have found some cases where quantum matters, buy not all.

electron transfer is a basic concept in metabolism, my specific application notwithstanding.

it would have been more accurate for them to have said "nonclassical quantum mechanics".

Atoms aren't stable in a classical universe.

that's a nonsense phrase.

Saying "quantum rules aren't important for most objects" just isn't true. I understand what you're trying to say -- that we mostly use imprecise metaphors in place of what's really going on -- but that's a statement about our understanding, not reality.

For example, solids are "solid" largely because of the Pauli exclusion principle, which says that two fermions (such as electronics) can't occupy the same state at the same time. These effects are so familiar, and we explain them with simple words like "solid," that we forget that quantum mechanics makes it work. Without quantum mechanics, we'd fall through the floor.

How about "the higher-level abstractions of biochemistry encapsulate quantum-mechanical effects pretty well, and rarely leak"?

That's hitting the nail on the head that is - right there. But telling a pedant what they do or don't need to be pedantic about is a losing game

Per a comment down thread that without quantum effects we'd all fall through the floor. Yes. But I don't need to solve Shroedinger's equation every time I go for a walk. In the same way, Biologists don't always have to take into account quantum mechanical effects, but the times that they do are very interesting and worth hearing about.

I briefly scanned the PDF looking for "base stacking" because this seemed so analogous. The only mention of the phrase was in the title of a reference. It would have been nice for them to address this.

I hate when people talk about entanglement as some separate phenomenon, while it is actually an effect of considering non-local QM in local approximation -- such post should be titled "considering entanglement improves DNA model accuracy" which is catchy adequately to the true value of the paper. This way it is like calling a sports article "Goalkeeper foiled by... angular momentum!".

A more accurate title would be "We've found parameters for our simulation that gives a role to room-temperature entanglement a shot at being somewhat relevant to base pairing", by and large ignoring all that chromatin structure that also holds DNA together as well ( http://en.wikipedia.org/wiki/Chromatin )

Only eukaryotes have chromatin. Besides, even eukaryotic DNA doesn't spend all its time as chromatin. Base pairing is still important, especially during replication and translation.

Yes, fully agreed. Base-pairing as a regular chemical process is vital.

This is probably a naïve question, but what examples exist of room-temperature entanglement naturally occurring? In other words, are we dealing with an entirely new phenomena or is this a "routine" phenomena being postulated to be found in a really cool place?

It's worth noting that entanglement happens pretty much all the time, all around you. Long-lived entanglement is a lab phenomenon though - it's only significant when we arrange the system so we actually preserve it for a usefully long amount of time.

Yes, this is something I wish was elaborated upon more. Entanglement isn't some strange process that rarely occurs. It occurs with all particles of matter at once due to the fact that the wavefunction that describes a system is a function of all particles. It just so happens that if some portions of matter are well isolated from another portion, then you can approximate the overall wavefunction by writing it as the product of two independent wavefunctions of two subsystems.

When there are noticeable effects that deviate from this approximation, that's what most articles are referring to as "entanglement".

If quantum mechanics is truly random at that level, and these mechanics affect biological processes, would that mean we do not live in a deterministic universe?

So if we restarted the universe from the exact starting conditions (imagine this can be done for sake of my point) then does this mean the universe would be different every single time?

> So if we restarted the universe from the exact starting conditions (imagine this can be done for sake of my point) then does this mean the universe would be different every single time?

Assuming there's such a thing as a universal wavefunction (which seems to be kind of debated), then yes, that is what quantum mechanics predicts at least.

If nothing else, radioactive decay is a quantum random process that has a biological effect when it alters DNA.

My understanding is that their work is more like "coupling" than "entanglement" (as the media describes entanglement). From the abstract of their arXiv article, it sounds like what they're looking at is the motion of the base pairs together. This is certainly pretty cool, but it's not quite the same as some of the other results on quantum entanglement where two particles are entangled and by observing one, you can infer the other, etc etc.

>There was a time, not so long ago, when biologists swore black and blue that quantum mechanics could play no role in the hot, wet systems of life.

When was this? Last February 31st? I don't recall any biologists discounting the last Nobel prize in Chemistry (which was biology and classical/quntum physics related as well).

the only example i can think of is the ongoing debate about whether or not a proton can undergo quantum mechanical tunneling in enzymes, which has been on and off debated for about 30 or 40 years. That electrons undergo quantum mechanical tunnelling in enzymes, though, has been uncontroversial for just as long, so it would be tough to say that biologists have rejected 'quantum mechanics' en banc.

There has been an on and off big deal about the so called Fenna-Matthews-Olson complex. Some people were big proponents of quantum coherence playing a role in its photosynthetic energy transfer mechanism (based on extrapolating from close to 0 K measurements, mind!)

Others (http://condensedconcepts.blogspot.com/2012/07/details-do-mat...) cast some doubt.

Ok, I'm vary far from expert in QM or physics for that matter and talking out of ass here. But here's my thought: Can we look at quantum entanglement as a result from a process that occurs between two objects in a different dimension free from dimension of spacetime. Currently we define entanglement as two objects effectively sharing the same existence, no matter how far apart they might be. But "far" (or distance) applies to the dimension of space which is limited by current known laws of relativity (speed of light) that's why entanglement sounds bazarre and spooky.

Entanglement is not limited by speed of light, since no information nor mass nor energy is exchanged.

You'd probably enjoy the wiki article on Implicate and Explicate Order: http://en.wikipedia.org/wiki/Implicate_and_explicate_order .

I wonder how many more decades it will take until a "technology" magazine ceases to put "weird" in front of quantum mechanics.

There was a time, not so long ago, when biologists swore black and blue that quantum mechanics could play no role in the hot, wet systems of life

Seems an odd thing to declare. Quantum mechanics is part of reality. Why would evolving things not eventually mutate to utilize aspects of reality -- especially those that operate at the atomic level?

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