4 ms·

Looking at the paper linked to in the article[1], I'm having a hard time not dismissing this immediately. There are several implications to this theory: - Info

by chroma 5y ago

Looking at the paper linked to in the article[1], I'm having a hard time not dismissing this immediately. There are several implications to this theory: - Information has mass. - Information cannot exist at absolute zero. Does this mean that bringing a hard drive to absolute zero changes its mass and erases its contents? Does the information somehow come back after the drive is warmed up? Also there are many ways to represent information: magnetic charges on a spinning platter, electrical charges in SSDs, physical impressions on metal, graphite on paper, etc. Do all of these get destroyed at absolute zero? I don't know how that's reconcilable with the rest of physics. 1. https://aip.scitation.org/doi/10.1063/1.5123794 https://aip.scitation.org/doi/10.1063/1.5123794

traskjd 5y ago
Armchair interest only, so please tell me if I'm wrong or at least we theorize how I could be wrong. My understanding is that even in the full vacuum of space, we do not get to absolute zero. Quantum fluctuations keep it ever so slightly above it. So perhaps information does actually not exist at absolute zero?
- chroma 5y ago
  According to the paper, the amount of information that can be stored decreases as one gets closer to absolute zero. Our current information storage technologies and refrigeration technologies don't let us actually test this, but with a high enough information density and a low enough temperature, one should expect to lose information if this theory were true.
- beaconstudios 5y ago
  Well I understand that information, like energy, cannot be destroyed (hence Hawking radiation) so it couldn't just be reduced to zero, it'd have to be transformed. Also the parent's argument about freezing and then reheating to destroy and restore information is a good one because that would be reversing entropy in a closed system (assuming the info was indeed destroyed) and thus impossible. IANA physicist though, just a lay person with an interest in information theory.
- zamalek 5y ago
  > My understanding Correct. The current zero point energy is believed to be a false vacuum (local minimum). One of the end-of-the-universe scenarios involve it tunelling to a lower state (bubble nucleation). Things become progressively more dire the lower the energy of the next (false or real) vaccum is, including matter and gravity ceasing to exist. Not only does this sound a lot like "no information at absolute zero," it is also a terrifying existential crisis (you're welcome).
doctoboggan 5y ago
As far as I understand it nothing can really ever be at absolute zero, it can only be asymptotically approached.
deleted 5y ago
[deleted]
colechristensen 5y ago
An atom cannot be at absolute zero, it is an unreachable extreme and all sorts of weird quantum effects go on as you try harder and harder.
jmf1sh 5y ago
Former mathematical physicist here. I haven't read the article yet so don't take this comment as a defense nor as a rebuttal, but I just want to point out that your reasons for immediate dismissal are not obviously valid. - The Bekenstein-Hawking black hole entropy directly relates information to entropy. There has been an "it from bit" program (and more recently "it from qubit") dating back decades that tries to treat information as somehow fundamental with matter/energy emergent. The jury is still out, but I wouldn't consider it to be particularly controversial (at least not moreso than other speculative theoretical physics). - To me it seems absolutely physically plausible that cooling a hard drive to absolute zero would destroy its contents. As another example, you can destroy the information contained in DNA at much warmer temperatures than absolute zero. Why would heating it back up restore the information? Most thermodynamic processes are irreversible. And by the way, thermodynamic irreversibility is related to entropy change, which is a measure of information lost.
- JohnHaugeland 5y ago
  > To me it seems absolutely physically plausible that cooling a hard drive to absolute zero would destroy its contents. Cool, cool. It doesn't, but enjoy. Why would you imagine this would happen? The magnetic domain is not affected thus, and neither are MOSFETs. You're a mathematical physicist? You're the single least likely person on Earth in my imagine to say "oh, you reduced the speed of some atoms? That must mean magic happens." What could possibly wipe a hard drive from the action of cooling it down? . > Why would heating it back up restore the information? In short form "it doesn't." You may be confusing that some heating processes create damage with the idea that warming something up will harm it. As any schoolchild can tell you, DNA has survived billions of years on this planet, being heated and cooled somewhat rapidly throughout.   > And by the way, thermodynamic irreversibility is related to entropy change, which is a measure of information lost. This is a very "consider a spherical cow" approach to physics. The reason physicists are made fun of on those grounds is that the abstractions they bring to the discussion are frequently so far divorced from the real world situation that by the time you start bringing the real world back to the discussion, their abstractions fall apart. Real world objects that were not designed for durability have not suffered this damage on the timescale of a fifth of the length of the universe. That things are irreversible and related to one another isn't much use when you look at the real world and the things you're describing aren't actually happening at large scale, even in uncontrolled natural conditions. An insect that's been in amber for 500 million years typically has DNA loss on the order of ~5%. It has been exposed to a wild range of temperatures. If you genuinely believe that exposing a hard drive to absolute zero would destroy it, help us understand why Voyager is still running. Maybe it's because it's still a tenth of a degree kelvin above absolute, or something?
rcxdude 5y ago
The connection between information entropy and thermodynamics entropy is pretty well established, as well as theories which relate the destruction of information to irreversability. This part of the article is actually not particularly controversial. The idea of a storage device gaining some mass when information in placed on it is not particularly new, but it is something which would be extremely difficult to measure. In terms of the question of absolute zero, you have to consider that the physical reality of a system at zero temperature (truely zero, not femtokelvin) and thus zero entropy is extremely weird: it would basically require a perfect crystal lattice extending infinitely in all directions. This is one of the reasons why it can't be reached. So the answer is basically that if you were to cool a hard disk to absolute zero (which is impossible), it would first require turning it into something not recognisable as a hard disk. (And if you're thinking we've come close to absolute zero in experiments, remember that the difference in scales between thermodynamic information/entropy and other information (even the information contained in the shape of a solid object, let alone any amount of information our current technology could store) is incredibly vast: the temperatures reached in labs don't really come close to that. So while this is still basically a theoretical idea (and likely will stay that way for some time without a very clever experimental design and a lot of resources: notice they basically propose building a LIGO to perform their experiment), it's not as weird as you might think, and the ways in which it is apparently weird reflect a weirdness that is already present in thermodynamics.

by chroma 5y ago

traskjd 5y ago

Armchair interest only, so please tell me if I'm wrong or at least we theorize how I could be wrong. My understanding is that even in the full vacuum of space, we do not get to absolute zero. Quantum fluctuations keep it ever so slightly above it. So perhaps information does actually not exist at absolute zero?

chroma 5y ago
According to the paper, the amount of information that can be stored decreases as one gets closer to absolute zero. Our current information storage technologies and refrigeration technologies don't let us actually test this, but with a high enough information density and a low enough temperature, one should expect to lose information if this theory were true.
beaconstudios 5y ago
Well I understand that information, like energy, cannot be destroyed (hence Hawking radiation) so it couldn't just be reduced to zero, it'd have to be transformed. Also the parent's argument about freezing and then reheating to destroy and restore information is a good one because that would be reversing entropy in a closed system (assuming the info was indeed destroyed) and thus impossible. IANA physicist though, just a lay person with an interest in information theory.
zamalek 5y ago
> My understanding Correct. The current zero point energy is believed to be a false vacuum (local minimum). One of the end-of-the-universe scenarios involve it tunelling to a lower state (bubble nucleation). Things become progressively more dire the lower the energy of the next (false or real) vaccum is, including matter and gravity ceasing to exist. Not only does this sound a lot like "no information at absolute zero," it is also a terrifying existential crisis (you're welcome).

doctoboggan 5y ago

As far as I understand it nothing can really ever be at absolute zero, it can only be asymptotically approached.

deleted 5y ago

[deleted]

colechristensen 5y ago

An atom cannot be at absolute zero, it is an unreachable extreme and all sorts of weird quantum effects go on as you try harder and harder.

jmf1sh 5y ago

Former mathematical physicist here. I haven't read the article yet so don't take this comment as a defense nor as a rebuttal, but I just want to point out that your reasons for immediate dismissal are not obviously valid. - The Bekenstein-Hawking black hole entropy directly relates information to entropy. There has been an "it from bit" program (and more recently "it from qubit") dating back decades that tries to treat information as somehow fundamental with matter/energy emergent. The jury is still out, but I wouldn't consider it to be particularly controversial (at least not moreso than other speculative theoretical physics). - To me it seems absolutely physically plausible that cooling a hard drive to absolute zero would destroy its contents. As another example, you can destroy the information contained in DNA at much warmer temperatures than absolute zero. Why would heating it back up restore the information? Most thermodynamic processes are irreversible. And by the way, thermodynamic irreversibility is related to entropy change, which is a measure of information lost.

JohnHaugeland 5y ago
> To me it seems absolutely physically plausible that cooling a hard drive to absolute zero would destroy its contents. Cool, cool. It doesn't, but enjoy. Why would you imagine this would happen? The magnetic domain is not affected thus, and neither are MOSFETs. You're a mathematical physicist? You're the single least likely person on Earth in my imagine to say "oh, you reduced the speed of some atoms? That must mean magic happens." What could possibly wipe a hard drive from the action of cooling it down? . > Why would heating it back up restore the information? In short form "it doesn't." You may be confusing that some heating processes create damage with the idea that warming something up will harm it. As any schoolchild can tell you, DNA has survived billions of years on this planet, being heated and cooled somewhat rapidly throughout.   > And by the way, thermodynamic irreversibility is related to entropy change, which is a measure of information lost. This is a very "consider a spherical cow" approach to physics. The reason physicists are made fun of on those grounds is that the abstractions they bring to the discussion are frequently so far divorced from the real world situation that by the time you start bringing the real world back to the discussion, their abstractions fall apart. Real world objects that were not designed for durability have not suffered this damage on the timescale of a fifth of the length of the universe. That things are irreversible and related to one another isn't much use when you look at the real world and the things you're describing aren't actually happening at large scale, even in uncontrolled natural conditions. An insect that's been in amber for 500 million years typically has DNA loss on the order of ~5%. It has been exposed to a wild range of temperatures. If you genuinely believe that exposing a hard drive to absolute zero would destroy it, help us understand why Voyager is still running. Maybe it's because it's still a tenth of a degree kelvin above absolute, or something?

rcxdude 5y ago

The connection between information entropy and thermodynamics entropy is pretty well established, as well as theories which relate the destruction of information to irreversability. This part of the article is actually not particularly controversial. The idea of a storage device gaining some mass when information in placed on it is not particularly new, but it is something which would be extremely difficult to measure. In terms of the question of absolute zero, you have to consider that the physical reality of a system at zero temperature (truely zero, not femtokelvin) and thus zero entropy is extremely weird: it would basically require a perfect crystal lattice extending infinitely in all directions. This is one of the reasons why it can't be reached. So the answer is basically that if you were to cool a hard disk to absolute zero (which is impossible), it would first require turning it into something not recognisable as a hard disk. (And if you're thinking we've come close to absolute zero in experiments, remember that the difference in scales between thermodynamic information/entropy and other information (even the information contained in the shape of a solid object, let alone any amount of information our current technology could store) is incredibly vast: the temperatures reached in labs don't really come close to that. So while this is still basically a theoretical idea (and likely will stay that way for some time without a very clever experimental design and a lot of resources: notice they basically propose building a LIGO to perform their experiment), it's not as weird as you might think, and the ways in which it is apparently weird reflect a weirdness that is already present in thermodynamics.