Can Lorentzian Relativity Unify Quantum Mechanics and Einsteinian Relativity?

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In summary: It's like saying that "length" is what rulers measure. They might be able to tell you the length, but they can't really measure it. Why is 'time is what clocks measure' any less satisfactory than 'length is what rulers measure'?I would say that "length", like "time" is just a concept, and not a... real thing. It's like saying that "length" is what rulers measure. They might be able to tell you the length, but they can't really measure it.
  • #1
mangaroosh
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I've been discussing Lorentzian and Einsteinian relativity here on PF, as well learning about them elsewhere, and a question occurred to me, and I thought that this might be the place to post it.

The problem of time, as I understand it, is based on the fact that quantum mechanics and Einsteinian relativity use different concepts of time; I've read that QM uses "a more Newtonian" concept. I'm just wondering if this issue would be the same under Lorentzian relativity, which also seems to incorporate a more Newtonian concept of time?

Given that both Lorentzian and Einsteinian relativity are not distinguished by means of experimental evidence, would it be possible to unify QM with Lorentzian relativity; are there any such attempts?

EDIT: I was going to add a point on the Wheeler-DeWitt equation, but I didn't think it was relevant, but if my understanding, that the mathematics of Einsteinian and Lorentzian relativity are the same, then perhaps it might be relevant.

My basic understanding if the Wheeler-DeWitt equation is that time does not appear in it, suggesting that the universe is timeless; while Lorentzian relativity includes the notion of absolute time, it is a short distance from the notion of absolute time to timelessness.
 
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  • #2
I like talking about time,

I can't make a question out of "The problem of time, as I understand it, is based on the fact that quantum mechanics and Einsteinian relativity use different concepts of time; I've read that QM uses "a more Newtonian" concept. I'm just wondering if this issue would be the same under Lorentzian relativity, which also seems to incorporate a more Newtonian concept of time?"

So what's up for discussion?
 
  • #3
Einstein defined time as the movement of a clock hand. In other words, the best he could come up with is that 'time is the measurement of time'. It struck me as completely unsatisfactory, and yet I've never heard any better. Hardest concept ever to define.
 
  • #4
Why is 'time is what clocks measure' any less satisfactory than 'length is what rulers measure'?
 
  • #5
Einstein defined time as the movement of a clock hand.

hmmmmm... and from that, clocks are variable but c is not?

what became of those Cern neutrinos that stepped to a different drummer ?
 
  • #6
russ_watters said:
Why is 'time is what clocks measure' any less satisfactory than 'length is what rulers measure'?

Then what do rulers do? Measure length? Seems a little hand-wavy to me? That's like in Thermodynamics when a book tries to define a state in terms of properties and then the next chapter defines the properties in terms of states. :tongue2: Just a thought, though. Maybe I am missing something (I usually do!).
 
  • #7
russ_watters said:
Why is 'time is what clocks measure' any less satisfactory than 'length is what rulers measure'?

hear hear

(of course ignoring the "human" aspect of the question)
 
  • #8
Hello mangaroosh,

Don't be confused, but QM works, and works quite well, when combined with Einstein's special relativity. And any Lorentzian form of physics is trumped by special relativity; so there's no point in going backwards.

Summary: relativistic QM and Einstein's special relativity use the same concepts of time (and spacetime, for that matter).

Points of interest:
  • Combining special relativity with quantum mechanics give rise to many predictions such as antimatter. And with a little more work (quantizing the fields themselves) give rise to quantum field theory which leads to things like photons and other force particles.
  • In academia, non-relativistic QM (which is more Newtonian) is taught first, since it's a lot easier. But it doesn't mean that special relativity and QM don't work together, it just means that you haven't gotten there yet.

It's QM and Einstein's general relativity that don't fit together well. QM, even relativistic QM, assume a flat spacetime (special relativity assumes a flat spacetime too), but with GR spacetime can be, and generally is, curved.

But spacetime (and time) in GR is really more-or-less the same interpretation of spacetime (and time) in special relativity; it's just that spacetime in GR is curved is all.
 
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  • #9
nitsuj said:
I like talking about time,

I can't make a question out of "The problem of time, as I understand it, is based on the fact that quantum mechanics and Einsteinian relativity use different concepts of time; I've read that QM uses "a more Newtonian" concept. I'm just wondering if this issue would be the same under Lorentzian relativity, which also seems to incorporate a more Newtonian concept of time?"

So what's up for discussion?

It's a topic I enjoy myself nit.

Up for discussion is anything to do with the nature of time really, but the question in the above is whether or not it would be possible to unify Lorentzian relativity with QM and to resolve the "problem of time"?
 
  • #10
russ_watters said:
Why is 'time is what clocks measure' any less satisfactory than 'length is what rulers measure'?
I would say that "length", like "time" is just a concept, and not a physical property of an object.

The question I would ask is, how exactly does a clock measure time; that is, how is the physical property of time measured by a clock?

If we take an atomic clock for example, it is the number of oscillations of a caesium atom which are measured (or counted), not some secondary physical property called "time".
 
  • #11
collinsmark said:
Hello mangaroosh,

Don't be confused, but QM works, and works quite well, when combined with Einstein's special relativity. And any Lorentzian form of physics is trumped by special relativity; so there's no point in going backwards.

Summary: relativistic QM and Einstein's special relativity use the same concepts of time (and spacetime, for that matter).

Points of interest:
  • Combining special relativity with quantum mechanics give rise to many predictions such as antimatter. And with a little more work (quantizing the fields themselves) give rise to quantum field theory which leads to things like photons and other force particles.
  • In academia, non-relativistic QM (which is more Newtonian) is taught first, since it's a lot easier. But it doesn't mean that special relativity and QM don't work together, it just means that you haven't gotten there yet.

It's QM and Einstein's general relativity that don't fit together well. QM, even relativistic QM, assume a flat spacetime (special relativity assumes a flat spacetime too), but with GR spacetime can be, and generally is, curved.

But spacetime (and time) in GR is really more-or-less the same interpretation of spacetime (and time) in special relativity; it's just that spacetime in GR is curved is all.
thanks Mark.

are you familiar with the term "the problem of time"; just wondering what your interpretation of it is?
 
  • #12
mangaroosh said:
are you familiar with the term "the problem of time";
Okay, I think I see what you're saying: things get weird near Planck scales. Under the hypothesis of quantum foam, spacetime is anything but flat at Planck scales. And since QM and GR don't play well together, GR isn't about to try and rescue anything.

I guess my original point though was that above Planck scales, QM and special relativity are already together, so there's no point in taking a step backwards into Lorentzian aether. That was really my only point.
 
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  • #13
collinsmark said:
Okay, I think I see what you're saying: things get weird near Planck scales. Under the hypothesis of quantum foam, spacetime is anything but flat at Planck scales. And since QM and GR don't play well together, GR isn't about to try and rescue anything.

I guess my original point though was that above Planck scales, QM and special relativity are already together, so there's no point in taking a step backwards into Lorentzian aether. That was really my only point.
Just to start with an extract from a paper:
Time is absolute in standard quantum theory and dynamical in general relativity. The combination of both theories into a theory of quantum gravity leads therefore to a “problem of time”.
Does time exist in Quantum Gravity?

Unfortunately, I don't fully understand the issue, but my understanding is that standard quantum theory doesn't incorporate the notion of gravity, while it is a central part of GR, to the extent that both are incompatible as they are i.e. quantum theory would require some formulation of gravity in order to be unified with GR - I'm not sure what would need to be changed in GR to marry it with quantum theory.

I was more just wondering if the aforementioned "problem of time" could be resolved through Lorentzian relativity, because it also uses the concept of absolute time.

From discussing it with some people on here, and according to the wiki entry (I haven't searched further yet) it appears that "neo-Lorentzian relativity" has effectively been stripped of everything but the concept of an undetectable, absolute rest frame - that includes the aether I think. Again, from discussing it with people, the postulation of this absolute rest frame appears to be one of the main reasons (the only one I have heard raised actually) as to why Einsteinian relativity is preferred over Lorentzian. I'm wondering, if the absolute rest frame were done away with, would it put Lorentzian relativity on par with Einsteinian, given that experiments do not distinguish between either?
 
  • #14
russ_watters said:
Why is 'time is what clocks measure' any less satisfactory than 'length is what rulers measure'?
It's not any less satisfactory. "Length is the measurement of length" would be just as unsatisfactory. Length can be explained relative to points and to the other dimensions, but there is nothing in the same class as time to compare it to. "Time is the measurement of time" is basically saying "time is time".
 
  • #15
zoobyshoe said:
It's not any less satisfactory. "Length is the measurement of length" would be just as unsatisfactory. Length can be explained relative to points and to the other dimensions, but there is nothing in the same class as time to compare it to. "Time is the measurement of time" is basically saying "time is time".

Did anyone ever try to define time in terms of (amount of) state change? From my armchair, that seems the most natural to me.
 
  • #16
MarcoD said:
Did anyone ever try to define time in terms of (amount of) state change? From my armchair, that seems the most natural to me.
There's ideas like that floating around out there, yes. Time and entropy, time and the second Law of Thermodynamics. (I would have to stand up and reposition my armchair to get a good look at them, and that's not going to happen.)
 
  • #17
zoobyshoe said:
It's not any less satisfactory. "Length is the measurement of length" would be just as unsatisfactory. Length can be explained relative to points and to the other dimensions...
Could you provide such a definition please? I can't see how what you describe is possible.
 
  • #18
russ_watters said:
Could you provide such a definition please? I can't see how what you describe is possible.

Length is one of the three physical dimensions. It's at right angles to width, and they are both at right angles to height. All three together describe a volume. Any two points that are not congruent can be said to delineate a length. A length is not a point, though. (A point has no length. It's a dimensionless location.) Length can be measured, but it isn't automatically a measure. All these concepts help define the others, and they can be illustrated with tangible objects and any x y z coordinates.

Time doesn't have a group of things in the same class that help define it.
 
  • #19
H. Minkowski said:
Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality.

So if if you accept that time is the measurement of time, then then you should also accept that length is the measurement of length.
 
  • #20
H. Minkowski said:
Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality.
I guess this hasn't happened yet because I've been staring at a ruler since you posted this and I still can't tell what time it is.
 
  • #21
zoobyshoe said:
Length is one of the three physical dimensions. It's at right angles to width, and they are both at right angles to height. All three together describe a volume. Any two points that are not congruent can be said to delineate a length. A length is not a point, though. (A point has no length. It's a dimensionless location.) Length can be measured, but it isn't automatically a measure. All these concepts help define the others, and they can be illustrated with tangible objects and any x y z coordinates.

Time doesn't have a group of things in the same class that help define it.
Having a group of things that all mean the same thing does not make the definition any less recursive, especially since you can rotate any object and just say "length is width." All three are just different names for distance when it is useful to differentiate by orientation. You're still just left with "length, width, height and distance are what rulers measure."

I find similar issues (not problems) with other properties like mass and volume.
 
  • #22
Jimmy Snyder said:
So if if you accept that time is the measurement of time, then then you should also accept that length is the measurement of length.

I think what Zooby is getting at is, we typically use length to measure length (e.g., a meterstick).

But we don't typically use time to measure time. Typically, we use a length and a rate of movement.
 
  • #23
zoobyshoe said:
I guess this hasn't happened yet because I've been staring at a ruler since you posted this and I still can't tell what time it is.
Really? An interval in the fourth dimension just like the other three. I could just as easily complain that my clock doesn't tell me length (except, of course, that it does :wink:).
 
  • #24
lisab said:
I think what Zooby is getting at is, we typically use length to measure length (e.g., a meterstick).

But we don't typically use time to measure time. Typically, we use a length and a rate of movement.
I doubt that's what he meant, especially since we do use time to measure time. I suppose you could make a clock that measured distance and speed, but I don't think I've ever seen one.

A quartz watch counts oscillations.
 
  • #25
You know, actually we already use time to measure length, sort of.

"No, we use meter sticks to measure length," one might say. Well, how long is a meter?

Since 1982, A meter is defined as ""The metre is the length of the path traveled by light in vacuum during a time interval of 1/299792458 of a second."

That's because the quantity c, the speed of light in a vacuum, is not a measured quantity anymore. It is a defined quantity.

c = 299792458.0000000... m/s, exactly.

So how is a second defined? A second is the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

I guess the point is, that if you hypothetically separate time and the measurement of time, in your mind's eye, and you let time somehow change such that it takes "longer" (whatever that means) for the 9192631770 periods to take place, a second would correspondingly be longer. But the meter stick would grow longer too. You desk, computer screen, house, earth, everything would be longer. Days and years would be longer too. But when you stop and look at it, nothing has changed.

I don't think there's any way to separate time from "measurement of time", and length from "measurement of length."

----------------

Now off on a side note tangent:

It was mentioned earlier that space can be represented in three dimensions that are perpendicular to each other. And in relativity anyway, time can be added as a fourth dimension, also perpendicular to the other three. Together they form spacetime. A differential length of spacetime, dS can be calculated using something similar to the Pythagorean theorem,

[tex] dS^2 = dx^2 + dy^2 + dz^2 - c^2dt^2 [/tex]

where time t is measured with the different units than length is measured with. But c is just a constant. It doesn't have to be measured in m/s. It could be measured in light seconds per second. Or light years per year. In other words, we can easily make c = 1 (no units). and in that case you can measure time in the same units that you use to measure length. Both time and length can have the same units. And with that, the line equation becomes.

[tex] dS^2 = dx^2 + dy^2 + dz^2 - dt^2 [/tex]
 
  • #26
collinsmark said:
It could be measured in light seconds per second. Or light years per year. In other words, we can easily make c = 1 (no units).
So which is it? Units of light seconds per second, or no units?
 
  • #27
Perhaps the point of that last rant of mine can be summarized in a hypothetical situation. Suppose you visit one of the TAI (International Atomic Time) laboratories, and say, "Oh, my. These atomic clocks in here keep pretty good time, huh?"

The answer you are likely to get back is, "No. These atomic clocks don't keep good time. Rather they define the passage of time. Oh, and we also use them to define length too, as long as we're at it."
 
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  • #28
Of course, i have been reading all of this and i still don't think that anyone has truly succeeded in answering what time is, so i will take a shot at it
OK, we live in the 3rd dimension, correct? if you currently are not in the 3rd dimension, please leave this forum and go to your respective dimension
back to the topic, we live in 3 dimensions. those dimensions can be described as length, height, and width.
if you don't know where I am going with this, there is a 4th dimension; time
as we live in the 3rd dimension, we move through the 4th dimension. we use seconds as a fundamental interval of this movement.
now, if you try to describe how general relativity works, imagine a grid that is all over this universe, that grid is affected by mass. whenever there is mass on this grid, it creates a depression just as a heavy person makes on a trampoline. of course, you probably already know this.
how this grid relates to the 4th dimension is that the grid itself moves through the 4th dimension.
now connecting this to correlations in QM time and relativity is quite simple...
unifying the time concepts would just be taking everything from one part of the two and mashing it with the others, work out the kinks with simple equations and algorithmic thinking and there you go, a unified concept of time. terrible explanation i know, but i am not very intellectual on QM's concept of time, i just use Einsteins theory of relativity because to me, it just seems the most correct. of course, until we can find a definite answer, which may never happen, both theories can be used to describe time. the ether theory just suggests a different form of a 4th dimensional medium of time, or at least that is how it can be interpreted.
hope this helps and correct me if I am wrong anywhere
 
  • #29
Jimmy Snyder said:
So which is it? Units of light seconds per second, or no units?
It depends on how you look at it I suppose. But once one realizes that they are one in the same (which is true for relativity anyway), the answer is "no units."

Time is definitely special though. Note the minus sign in the line equation, for example. I'm not saying time and length are exactly the same thing. But they can be measured with the same units. You can measure time in meters, or length in seconds if you wanted to.

Relativity (both special and general) shows us that time and length can warp into each other depending on the observers' frames of reference. For example, one observer might observe two events happening simultaneously, and at some distance apart. But another observer (in a different frame) observes the events happening at different times -- but the spatial separation is different than what the first observer observed.
 
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  • #30
This thread has been sufficiently answered.
 
  • #31
Evo said:
This thread has been sufficiently answered.
Not quite.

https://www.youtube.com/watch?v=oqeSUAlI5uI
Guess Who - No Time

https://www.youtube.com/watch?v=ARgiPJobKnE
Chambers Brothers - Time has come today

Turn up the volume :tongue2: according to preference - or not.


Now the problem is sufficiently answered. :biggrin:
 

1. Can Lorentzian Relativity unify quantum mechanics and Einsteinian relativity?

This is a highly debated and complex question in the field of physics. Some scientists believe that Lorentzian relativity, also known as Lorentz symmetry, can provide a framework for unifying quantum mechanics and Einsteinian relativity. However, others argue that a complete unification is not possible or necessary.

2. How does Lorentzian Relativity differ from Einsteinian relativity?

Lorentzian relativity is based on the work of Hendrik Lorentz and Albert Einstein, while Einsteinian relativity is solely based on Einstein's theories. Lorentzian relativity includes the concept of Lorentz symmetry, which states that the laws of physics are the same for all observers in uniform motion. This differs from Einsteinian relativity, which proposes that the laws of physics are the same for all observers, regardless of their motion.

3. What evidence supports the idea of Lorentzian Relativity unifying quantum mechanics and Einsteinian relativity?

There is currently no conclusive evidence that supports the idea of Lorentzian relativity fully unifying quantum mechanics and Einsteinian relativity. However, some studies have shown that Lorentz symmetry may play a role in certain phenomena, such as the behavior of high-energy particles.

4. Are there any challenges or limitations to using Lorentzian Relativity as a unifying theory?

One of the main challenges to using Lorentzian relativity as a unifying theory is that it does not fully account for the principles of quantum mechanics, such as uncertainty and entanglement. Additionally, there is no consensus among scientists on whether Lorentz symmetry is a fundamental principle or an emergent phenomenon.

5. How does the concept of Lorentzian Relativity impact our understanding of the universe?

The concept of Lorentzian relativity has greatly impacted our understanding of the universe, particularly in the fields of cosmology and particle physics. It has played a crucial role in developing theories such as the Standard Model and the Big Bang theory. However, its exact role in unifying quantum mechanics and Einsteinian relativity is still a topic of debate and further research.

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