> So a time crystal is a phase of matter that spontaneously breaks this translation symmetry in time, to show you some kind of periodic, pulsing forever.
As long as people understand this means perpetual motion which is incapable of doing work is possible, because there's no indication that you can somehow extract anything from this.
It does make me wonder whether this could help with reversible computing, which reverses out everything except its output, which is all you pay energy for. In theory that would be vastly more efficient.
observation requires the transmission of information to the observer, how is it being proposed to do this without force? The question on the table is "constructing a toy which demonstrates" and demonstration requires observation, I think is what is being said
he's saying you can't observe the phenomenon you are talking about without some additional work being done, which you might say is not part of the system, but it is part of the system that G*P proposed
I suspect it should be possible to have something that reflects light without doing work, or at worst absorbs a small portion of the incoming light and reflects the rest. Since it will sit on a desk, it will always be under light when observed by humans.
To my very lay understanding, many quantum phenomena effectively "borrow" energy and then "repay" it. I wonder if one day we might find a way to delay that repayment long enough to accomplish things we otherwise couldn't.
That's only one plausible ending to the universe, while perhaps favored, certainly far from being determined.
Then there's handwaving about given a large enough time scale energy should randomly concentrate enough to 'restart' the universe or something silly along those lines.
For myself I like the notion of the universe starting from a breaking of symmetry of whatever base form of energy the universe is built out of.
This allows for scattering of information, increasing diversity and complexity of the system, while also not adding or creating any new energy.
So if the universe can start in a place of equilibrium I'd imagine after heat death leads to a static state then 'restarting' is possible since it's happened at least once.
That's perpetual motion machines, not perpetual motion. As a closed system, the universe (as a whole, not in parts) absolutely qualifies as being in perpetual motion, you just can't take energy out of the system.
(which is convenient for us, because we're part of the system)
Okay sure, it’s just that no one uses the term “perpetual motion” except to refer to perpetual motion machines as I described. Even the Wikipedia article on the topic is titled “perpetual motion.” And the entire universe, as far as we know, is not in perpetual motion. i.e. does not violate the laws of thermodynamics.
No (serious) person uses it for the quantum scale either. Same problem, just other end of the scale. The very idea of "motion" doesn't even apply to quantum particles.
Lol, you think this it's the physicist choosing the headline? I mean, there are some dumbass physicists out there that will do anything for attention (max tegmark, Neil Tyson, etc.), but come on.
The alchemist Cornelis Drebbel successfully harnessed what he considered to be the perpetual motion of the universe for his perpetual motion machine...
... that now we know to have been changes in temperature and atmospheric pressure, both concepts which were very fuzzy at the time, especially the pressure.
Sadly, his machine had made such an impression, that the legend of it then continued to plague patent applications for centuries !
Everything in this universe is in perpetual motion. Perpetual motion is trivial. Now, perpetual motion energy... now we have something to which the answer is and will always be "no".
Remember how superconductivity is about the complete (?) removal of friction thanks to quantum behaviour ?
Also this talk of quantum toys convinces me even more that the right framing is instead how our (subjective) information about a system can only decrease with time (or stay unchanging for exceptional systems such as these).
I was surprised superconductivity wasn't mentioned.
The new part here isn't the "perpetual motion" it's the complexity of the pattern.
I guess in some highly abstract sense it's like exciting a more complex resonance mode in a bounded system. The simplest mode gives you a simple output, more complex modes give you more complex outputs.
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[ 2.7 ms ] story [ 101 ms ] threadIsn't this Maxwell's Demon?
Pulsing is just standing still, but with a bit extra flair.
https://news.ycombinator.com/item?id=26908886
https://en.wikipedia.org/wiki/Landauer%27s_principle#Challen...
https://en.wikipedia.org/wiki/Reversible_computing
> Due to the unitarity of quantum mechanics, quantum circuits are reversible, as long as they do not "collapse" the quantum states they operate on.
If so, then you could only have one that contains an unobservable perpetual quantum process; well, you’d need to trust that the seller that it does!
I mean, it hasn’t stopped yet, right? And it technically does all the work we do?
Seriously thou: it seems reasonable to assume that our current models of the universe may be incomplete.
Then there's handwaving about given a large enough time scale energy should randomly concentrate enough to 'restart' the universe or something silly along those lines.
For myself I like the notion of the universe starting from a breaking of symmetry of whatever base form of energy the universe is built out of.
This allows for scattering of information, increasing diversity and complexity of the system, while also not adding or creating any new energy.
So if the universe can start in a place of equilibrium I'd imagine after heat death leads to a static state then 'restarting' is possible since it's happened at least once.
(which is convenient for us, because we're part of the system)
First there was nothing, then there was everything. For currently undefined values of "first" and "then."
It's very much an out-of-scope problem.
The alchemist Cornelis Drebbel successfully harnessed what he considered to be the perpetual motion of the universe for his perpetual motion machine...
https://antonhowes.substack.com/p/age-of-invention-why-wasnt...
... that now we know to have been changes in temperature and atmospheric pressure, both concepts which were very fuzzy at the time, especially the pressure.
Sadly, his machine had made such an impression, that the legend of it then continued to plague patent applications for centuries !
Also this talk of quantum toys convinces me even more that the right framing is instead how our (subjective) information about a system can only decrease with time (or stay unchanging for exceptional systems such as these).
The new part here isn't the "perpetual motion" it's the complexity of the pattern.
I guess in some highly abstract sense it's like exciting a more complex resonance mode in a bounded system. The simplest mode gives you a simple output, more complex modes give you more complex outputs.