Is Time Real?

[rajnz00]

hyksos, according to Wikipedia, Semiclassical gravity treats matter fields as being quantum and the gravitational field as being classical. No great logic behind it and it apparently doesn't work.

Quantum gravity theories are still unproven and problematic. They usually take space and time to either both continuous or both discrete. But some have only space or only time as discrete.

In quantum theory there is something called the Correspondence Principle, which says when you use quantum theory to describe things that can be described with classical mechanics, then quantum theory must give the classical result, which it does.

But I think the Correspondence Principle should be a general rule for all theories which yield greater insights. They must accommodate the theory they are replacing. Even the round Earth accommodates the flat Earth, but not vice-versa.

[rajnz00]

DragonFly on January 17th, 2017, 4:58 pm wrote: We have a free lunch, if not a universal feast:

"...matter’s very readily made—
Underlying energy raising the shades."

Dave is complaining he has no bread. Methinks let him eat cake.

[Dave_Oblad]

Hi Raj,

And the most famous person that said something like that got their head chopped off.. lol.

I have plenty of Bread and Cake, I just don't have a lot of Time ;)

I'm trying to extract myself from this thread.. I've said what I needed to say.. anything more would have to be redundant.

Please: Don't poke the sleeping bear. (it's rude among other things)

Best Regards,
Dave :^)

[hyksos]

But I think the Correspondence Principle should be a general rule for all theories which yield greater insights. They must accommodate the theory they are replacing. Even the round Earth accommodates the flat Earth, but not vice-versa.

This would fork away from the thread. I don't have any solid indication a new thread on this topic would draw readers and replies.

Richard Feynman is really going to have a lot to say about this. If you take Feynman Path integral and pretend like the Planck's Length goes to zero, then after about 2 chalkboards of algebra and other mathematical manips, the Principle of Least Action pops out at the end.

On some philosophical/ontological level , (or say in the context of "watercooler philosophy") we all pretend like Quantum Mechanics is somehow absolutely opposed to classical physics. Even contrary to it. But inside the technical discipline of physics, quantum mechanics contains classical Hamiltonian mechanics as a limiting case. The method of taking-planck-length-to-zero is basically an approximation, justified because the Planck length is "essentially" zero compared to objects that are the size of trees, cars, and basketballs.

I have a (amusing) PDF about this topic if this topic is of interest to you. In the PDF the author basically says

Thus, classical mechanics becomes a short-wave approximation of quantum mechanics,

[rajnz00]

Dave_Oblad » January 18th, 2017, 5:17 am]I've said what I needed to say.. anything more would have to be redundant.

I think we all have.

If there is one thing that needs to be pointed out - it's that when we refer to Time we are talking about two different things, while using the same word. One is that which is used to measure the ordering of events, which is not the same as the “Time” used to measure duration.

While the cosmological, thermodynamic, electromagnetic, memory, and biological, arrows of time still exist, ronjanec has convinced us there is no such thing as time.

Funnily enough though I have run out of it. Let me know when Ligo spots our past, I'll come back to admit I was wrong.

Cheers

Raj

[mitchellmckain]

I have a (amusing) PDF about this topic if this topic is of interest to you. In the PDF the author basically says

Thus, classical mechanics becomes a short-wave approximation of quantum mechanics,

Truth be told, all of physics is an approximation to real life -- however enticing its mathematical precision, it is no substitute for actual living.

[ronjanec]

A very interesting and excellent thread Raj! Nice job. I really enjoyed both participating here, and learning some new things from you and others.

[hyksos]

hyksos, according to Wikipedia, Semiclassical gravity treats matter fields as being quantum and the gravitational field as being classical. No great logic behind it and it apparently doesn't work.

rajnz00, ignore Semiclassical Gravity theory at your own peril. The theory predicts very exotic things having to do with accelerated observers. These predictions could give rise to technologies which would be unimaginable in the 20th century.

For example : https://en.wikipedia.org/wiki/Sokolov%E ... nov_effect

[rajnz00]

hyksos, from the link you have given, the Sokolov–Ternov effect does not appear to have any relation to semi classical gravity. Its applications so far are that it "provides a unique capability for creating polarized beams of high-energy electrons and positrons that can be used for various experiments."

And semi classical gravity theory is being used to "understand the Hawking radiation of black holes and the generation of random gaussian-distributed perturbations in the theory of cosmic inflation, which is thought to occur at the very beginnings of the big bang." https://en.wikipedia.org/wiki/Semiclass ... plications

Nothing in those to indicate "The theory predicts very exotic things having to do with accelerated observers. These predictions could give rise to technologies which would be unimaginable in the 20th century."

[hyksos]

hyksos, from the link you have given, the Sokolov–Ternov effect does not appear to have any relation to semi classical gravity.

Woops@ I guess the effect can be derived purely from SR considerations. The bottom of the article mentions both Hawking Radiation as well as the Unruh effect. (see See Also).

The amount of additional heat from Unruh is a formula that looks totally identical to the formula for the temperature of a black hole. My mistake is totally forgivable given that there exist peer-reviewed articles which suggest that Sokolov-Ternov is the same effect as Hawking radiation for an circularly-accelerating observer. (e.g. https://arxiv.org/abs/hep-ph/0610391 ) In this sense you are technically not right in your claim that it "does not have any relation to".

Taking all such elements as a whole, you can see why I would have mistakenly attributed the Sokolov-Ternov effect to a prediction of semi-classical gravity. Pardon me for the mixup.

[dandelion]

If interested, this may help with some impression of Barbour’s views, and in the audience, Smolin asks questions towards the end.
http://www.perimeterinstitute.ca/videos ... relativity

[rajnz00]

Now here is something interesting:

Scientists Create A New Kind Of Matter: Time Crystals

two teams of researchers have figured out that crystals' repeating patterns can also exist through time. These "time crystals," detailed in a new paper in Physical Review Letter, are an entirely new kind of matter, one that can never reach equilibrium.

To create the time crystals, researchers at University of Maryland hooked together 10 ytterbium atoms and hit them with two lasers multiple times to keep them out of equilibrium. Though the atoms did settle into a pattern, they could not reach equilibrium, meaning that the crystals perpetually remain in motion, though they don't contain any energy. Almost all of physics is based in studying matter that is at equilibrium, so the ability to create these non-equilibrium crystals is a huge deal for the future of physics.

"This is a new phase of matter, period, but it is also really cool because it is one of the first examples of non-equilibrium matter," lead researcher Norman Yao from the University of California, Berkeley told EurekaAlert!.

The idea of time crystals—a form of matter that appears to move even at its energy-less ground state—was first proposed by Nobel-Prize winning theoretical physicist Frank Wilczek in 2012. Usually, if matter is in its ground state, movement should be impossible, because it contains no energy.

The researchers say that time crystals resemble Jell-O. When you tap Jell-O, it jiggles. The only difference is that the crystals are jiggling without using any energy, without any tap. By definition, time crystals can never stop oscillating, no matter how little energy they contain.

Right now, it's unclear what the practical use of this discovery will be [Yep but they will be huge. Stuff the discoverers could never dream of], but it's possible that these crystals could serve a function in quantum computers.

Source: Physical Review Letters via EurekaAlert!

[rajnz00]

Time Crystals - are these perpetual motion machines, that tap into the energy of space? The Big Bang?

[rajnz00]

Physicists Haruki Watanabe at the University of California at Berkeley and Masaki Oshikawa at the University of Tokyo "proved" in 2015 that Time crystals cannot exist. Just like scientists had "proved" that heavier than air flight was "impossible" just before 2 bicycle mechanics flew their plane anyway.

But here's the interesting thing about their paper.

The only difference between the two [ordinary crystals and time crystals] is that the first involves spatial long-range order while the second involves temporal long-range order. Although space and time are often considered to be closely related, together forming the "fabric of spacetime," the findings here emphasize a subtle yet fundamental difference between space and time—with a result that allows for the existence of crystals in one dimension, but forbids them in the other. -(You were WRONG buddy boys.)

They are 2 separate things. Methinks Smolin was right - Time is real and Time exists, this probably proves it.

[mitchellmckain]

Time Crystals - are these perpetual motion machines, that tap into the energy of space? The Big Bang?

No they are not! They are driven by an external source of energy via the lasers. This is what is meant by a non-equilibrium state of matter -- constantly getting energy input from an external source. Frankly this discovery does not look very extraordinary to me. It looks like a pretty simple extension of some very basic physics of simple harmonic oscillators.

However, the potential use for quantum computers is intriguing. It makes sense to me because it would move electronics towards living organisms in a very fundamental way because living organisms are definitely in the regime of non-equilibrium matter.

[rajnz00]

mitchellmckain on January 31st, 2017, 4:00 pm wrote: No they are not! They are driven by an external source of energy via the lasers. This is what is meant by a non-equilibrium state of matter -- constantly getting energy input from an external source.

I see? Much like you taking a quartz crystal and tapping it continuously with a hammer? Maybe you could do that and produce a quantum computer.

Somehow I thought it was different. The lasers were only used to produce the effect and the crystals were in perpetual motion thereafter, though their atoms were in a ground state. But maybe you know better since you are so emphatic about it. Wonder what the fuss was all about?

[mitchellmckain]

mitchellmckain on January 31st, 2017, 4:00 pm wrote: No they are not! They are driven by an external source of energy via the lasers. This is what is meant by a non-equilibrium state of matter -- constantly getting energy input from an external source.

I see? Much like you taking a quartz crystal and tapping it continuously with a hammer? Maybe you could do that and produce a quantum computer.

Somehow I thought it was different. The lasers were only used to produce the effect and the crystals were in perpetual motion thereafter, though their atoms were in a ground state. But maybe you know better since you are so emphatic about it. Wonder what the fuss was all about?

Media and science writers always add a lot of hype in order to grab the attention of non-scientists. It produces misunderstanding but most would say that is better than just being ignored. Misunderstandings can be corrected but being ignored shows how a lack of misunderstanding does not equal more understanding -- quite the opposite.

This news is not without intriguing aspects and every new avenue of scientific investigation opens up new possibilities for research and technology.


The difference from a quartz crystal is that instead of just vibrating without changing the crystalline structure, in the time crystal the molecules are actually moving to different locations in the whole structure. It means the theoretical physics describing crystals might be altered in a significant way and that means the possibility of new discoveries coming from the altered mathematics.

[rajnz00]

mitchellmckain on January 31st, 2017, 4:00 pm wrote: No they are not! They are driven by an external source of energy via the lasers. This is what is meant by a non-equilibrium state of matter -- constantly getting energy input from an external source.

You are wrong about that, despite being so emphatic about it,

There is no "constantly getting energy input from an external source". There would be absolutely nothing spectacular about that. Very mundane like continuously hitting a quartz crystal with a hammer.

And the difference with a quartz crystal is not "that instead of just vibrating without changing the crystalline structure, in the time crystal the molecules are actually moving to different locations in the whole structure." but that 1. the molecules in crystals of quartz are not in a ground state and 2. not in perpetual motion without an external power source.

[mitchellmckain]

mitchellmckain on January 31st, 2017, 4:00 pm wrote: No they are not! They are driven by an external source of energy via the lasers. This is what is meant by a non-equilibrium state of matter -- constantly getting energy input from an external source.

You are wrong about that, despite being so emphatic about it,

There is no "constantly getting energy input from an external source". There would be absolutely nothing spectacular about that. Very mundane like continuously hitting a quartz crystal with a hammer.

Yes there is. It is what a non-equilibrium state means! What you are imagining with the words "perpetual motion machine" would be an equilibrium state. And just because it isn't as spectacular to the impossible degree you chose to imagine, does not mean that it isn't a significant scientific breakthrough.

What you are thinking of is the original idea of a time-crystal in thermal equilibrium by Watanabe and Oshikawa which they proved could not actually exist. The new discovery is an extension of this idea to a non-equilibrium system (i.e. driven by an external source of energy). You can follow the link there to the MIT article. Energy enters the system via the lasers flipping the spin of ions in the material. The startling discovery was that the frequency of changes in the time structure of the crystal was not sensitive to the frequency of the driving lasers flipping the spins of the ions. So there definitely is energy entering the system but it is not directly driving the oscillations of the time crystal.

And the difference with a quartz crystal is not "that instead of just vibrating without changing the crystalline structure, in the time crystal the molecules are actually moving to different locations in the whole structure." but that 1. the molecules in crystals of quartz are not in a ground state and 2. not in perpetual motion without an external power source.

Incorrect. That is NOT the difference from a time-crystal that is the difference between a quartz crystal vibrating due other things and the driven vibration in the quartz used in a applications like a watch.

[rajnz00]

mitchellmckain on January 31st, 2017, 6:20 pm wrote: What you are thinking of is the original idea of a time-crystal in thermal equilibrium by Watanabe and Oshikawa which they proved could not actually exist.

Where did you get thermal equilibrium from? What they claimed to have “proved” was crystals can exist in the spatial dimension but cannot exist in the temporal dimension.

Theoretically though, if they could, then, like crystals breaking spatial symmetry, they would break time symmetry. If then they were cooled down to their ground state, they could be made to, if arranged in a ring, to “vary periodically in time”. In other words, move periodically, perpetually, without any input of energy.’

Now whereas Munroe and co (and some other guys with diamond), haven’t quite done that, they have shown that “[there was] no driving force with that period, the only explanation is that the time symmetry must have been broken, thereby allowing these longer periods. In other words, Monroe and co had created a time crystal.”

It seems to me that they have proven, in principle, that Watanabe and Oshikawa were wrong. And that Time crystals, (crystals that exist in the temporal dimension, a new state of matter), can exist and thus be capable of perpetual motion, if shaped in a ring at least.

[mitchellmckain]

I give up. I tried to explain it to you, but you either cannot understand, don't want to hear or both. Everything I explained is there in the report by the scientists who made the discovery. I don't see any point in continuing to explain it when all that is left is to repeat myself. So that is the end of the discussion on the matter with me.

[rajnz00]

I have quoted exactly from the link you sent me and that is precisely what it says. You jumped in with your own explanation. First you say "Frankly this discovery does not look very extraordinary to me. It looks like a pretty simple extension of some very basic physics of simple harmonic oscillators." Though it's nothing like that. Then you said it was "a significant scientific breakthrough". Make up your mind. And then stuff like Watanabe and Oshikawa talking about crystals in thermal equilibrium and all that nonsense about quartz crystals. Seems like you just make up things as you go along.

[hyksos]

rajnz00,

Watanabe and Oshikawa showed that time crystals are forbidden in thermal equilibrium. The researchers at Maryland agree with the proof.

How do I know this? Because the lab techs at University of Maryland said this exact thing -- in the abstract of their paper in 2016. Given your energy and emotional fireworks, I would suppose you have read this paper. (Good lord, I hope you have read the paper.)

The outer ring of ytterbium ions will have a periodic circular motion. The researchers refer to this as a "global rotation". If the global rotaiton is "sub-harmonic" to the frequency of the ions in their ground state, then those ions will neither absorb energy from the rotation, nor give any back,and that is an expected outcome due to the discrete nature of quantum particles. When the dust settles, a very long stability is expected in those systems. (..eternal stability? )

What does all of this mean? Generally, the Space-Time Crystal experiments are messing around in the boundary between classical and quantum systems. Despite all the cavalier grandstanding of modern physics, this boundary is not really understood. The research is fundamentally part of something called Condensed Matter physics. Secondarily , it can be referred to as "periodically-driven quantum systems". Googling such phrases will crack open a portal into the world of this branch of physics research.

Nobody in this thread is "out for blood" (although this can't be said of all regular users present on this forum.. cough-cough) Your text is becoming increasingly drenched in italicized words and bold-face. For the sake of your own blood pressure, my honest suggestion is to disengage yourself from having a personal stake in the topic of Space-Time Crystals. Try to avoid a situation where any and all challenges and clarifications of the research are received by you as a direct attack on your character.

[rajnz00]

Hyksos, so these time crystals that were produced were not in equilibrium, big deal. There is no such thing as an isolated system anyway. Everything interacts with everything else eventually. Gravity waves get through the thickest of walls, stars, you name it. That doesn’t mean that that this guy mitchellmckain can come charging in and get away with spouting loads of garbage. Claptrap such as “Yes there is. It is what a non-equilibrium state means!”. A non-equilibrium state is simply one where energy flows from one direction to another. It can flow in or out. Fellow makes out like he’s Einstein, unfortunately he doesn't appear to be so.

To my saying that “1. the molecules in crystals of quartz are not in a ground state and 2. not in perpetual motion without an external power source.” Which is precisely correct. He responded “that is the difference between a quartz crystal vibrating due other things [what “other things”??] and the driven vibration in the quartz used in a applications like a watch.” What claptrap. Somewhere else he claimed he could work out that the apparent diameter of the Sun was 1/720 that of a circle using his naked eye and lines on the ground for counting, or some such thing. The guy must be a genius.

Rather like a conman fortune-teller who tells you one thing correct about your past, because he has planted an accomplice outside his room and you have told him, (in this case looked it up online) and then proceeds to spout a whole lot of hogwash about your future. Utterly missing the point that time symmetry was broken by these guys.

First he says "Frankly this discovery does not look very extraordinary to me. It looks like a pretty simple extension of some very basic physics of simple harmonic oscillators." Simple harmonic oscillators! Then after having shot his mouth off with that garbage, he must have read further and comes out with "a significant scientific breakthrough". Indeed!

[TheVat]

Mod note: the above post doesn't meet the basic level of courtesy expected at SPCF. The ban is for 7 days.

[mitchellmckain]

Let's sum things up.

1. This is not an example of a perpetual motion machine.
2. Time-crystals cannot exist in the conditions of thermal equilibrium.
3. Time-crystals can exist in non-equilibrium conditions (i.e. with an outside source of energy).
4. It is a significant breakthrough for two important reasons.
a. There is the extension of the science for crystals into the time dimension.
b. It advances the development of non-equilibrium physics.
5. Media hype serves a purpose, but it should lead us to get the actual facts from the scientific papers.

[RoccoR]

Good Morning All,

It took me a while to read all the posting.(Metaphysics & Epistemology --- Is Time Real.)

Many of the contributors have it (in various ways) correct. Time is merely the duration between two (or more) events.

It is simply part of the universal coordinate. When you give the "x" by "y" by "z" coordinate location of something in the universe, we generally leave off the "t" for time. Everything in the universe moves; to give an accurate coordinate, you must include "t" for time. Otherwise, we consider "t" irrelevant. (t) = ∆s/∆t The formula is Time is equal to Distance divided by Speed.

The question is not "is time real." The question is what unit of measure we use with what standard; such that every one can replicate the computation and agree on a time. there are several to choose from in the universe. One such might be the radio sources [Cepheid Variables, Pulsars, or fast radio bursts (FRBs)] that pulsated very regularly with periods of just fractions of a second to a few seconds; with Speed being an expression for the rate at which an object moves relative in a frame of reference.

Everything in the universe is in motion. The duration between one coordinate and the next coordination is a man-made increment called time.

Most Respectfully,
R

[rajnz00]

Let’s sum things up:

1. Watanabe, Oshikawa, in their paper never mentioned “thermal equilibrium”.
2. What they did was to “first propose a definition of time crystals in the equilibrium” They then “proved” that time crystals defined as such, “in the equilibrium with respect to an arbitrary Hamiltonian which consists of not-too-long-range interactions”, whatever the heck that means, could not exist.
3. Before that, Frank Wilczek had proposed theoretically that Time crystals could exist and Tongcang Li,et al, had proposed how, by confining ions in a ring, with a static magnetic field, in a ground state, a space-time crystal could be created experimentally. These ions, aka “time crystals” would be periodic both in time and space.
4. Time crystals can exist therefore theoretically, and be in constant motion, without an outside source of energy.
5. Scientists following up on their suggestions have created A New Kind of Matter: Time Crystals.
6. It is significant because
a) It is a new kind of matter
b) We have no idea what the future uses or implications might be
c) Anything else stated about its significance, is trite meaningless drivel.
7. It would be terribly unimaginative not to realise this.

[rajnz00]

RoccoR, "The duration between one coordinate and the next coordination is a man-made increment called time." What do you mean by that? What do you mean by the "next coordination"
It seems to me you are talking about Time as duration, which is fine, but what about the Time as that thing which determines the order of events? That ensures that we are born and grow old before we die, that separates the past from the future and which determines the fleeting Now?

[RoccoR]

rajnz00, et al,

Yes, you are understanding correctly. Time is not a thing. Time is is a component to a coordinate.

IF you understand that the universe, all of it, including that which is beyond of (the 14B year) visible horizon, is in motion --- THEN Time is equal to Distance divided by Speed; calculated in any uniform increments you wish. Which the universe, the standard pulse of a cepheid star can be considered a galactic standard (with a regular radial-pulsating stars, defined period-luminosity which can be used as primary distance --- standard candle).

The order of events cannot be observed as ordered until they are compared in time with a defined standard. Otherwise, time has no meaning and the concept of your "order of events" has not meaning. Time DOES NOT order events. Events are considered ordered using time.

The duration between one coordinate and the next coordination is a man-made increment called time." What do you mean by that? What do you mean by the "next coordination?"

(ANSWERS)

I am on the side of Einstein in the argument with Bohr–Einstein debates; “I like to think that the moon is there even if I am not looking at it.”

Everything in the universe is in motion; including any Cepheid Star you choose as a standard candle.

• The distance a Cepheid Star moves between its pulses can be used be used by any sentient being that has it under observation.
• The observance of a duration between pulses can be used as a universal increment in time by any sentient being.
• The distance it moves between the its pulse (zero) and the pulse (pulse one), (two different coordinates) can be used as an standard increment is distance.

Now you have everything a sentient being, here on Earth or elsewhere in the universe, to agree upon in terms of time, distance, and speed --- under the Euclidean Geometry, Newtonian Mechanics and General Relativity.

Time means nothing if there is no observing sentient being. Yet the duration between the location of any two events, or the pulses rate of a Cepheid Star are still there even if there are no sentient beings in the universe to discover and measure them.

Most Respectfully,
R