Infinite Universe and Parallel Universes

[RyanH42]

If we suppose universe is infinite than there will be no parallel universes.So I know that If ##Ω_k##→Universe will be infinite.Then there will be no parallel universes cause there's one universe.
I am confused.Is that mean the parallel universe idea is wrong ?

 

[Chalnoth]

If we suppose universe is infinite than there will be no parallel universes.So I know that If ##Ω_k##→Universe will be infinite.Then there will be no parallel universes cause there's one universe.
I am confused.Is that mean the parallel universe idea is wrong ?

It's wrong on a few counts.

1. There's no way to know whether or not the universe is infinite. For example, we can't measure a curvature of identically zero: there will always be some error in our measurements, so we can never say that the curvature is perfectly flat. And even if we could, there are ways to write down a universe that is perfectly flat but is, nevertheless, finite (such as the toroidal universe).
2. It's perfectly plausible to write down models where our universe is infinite, but that there are other, disconnected regions which our universe cannot communicate with. One such model would be from string theory, where our universe is a 4-dimensional brane. This brane could be infinite in extent, and there could be another infinite brane that is separated from our own across a fifth direction that we can't access within our four dimensions of space-time. This sort of universe would be parallel in the literal meaning.
3. The quantum multiverse occupies the same space and time, but is separated into "worlds" that cannot communicate with one another.

 

[tom aaron]

If we suppose universe is infinite than there will be no parallel universes.So I know that If ##Ω_k##→Universe will be infinite.Then there will be no parallel universes cause there's one universe.
I am confused.Is that mean the parallel universe idea is wrong ?

Being in the sciences my first response is the same as most issues. The need to define a term. What do you mean by 'universe'. What is meant by 'Infinite'...what is meant by 'parallel', etc.

The above question needs to be posed with reference to some author's work.

 

[RyanH42]

Think a box, box is space time.Its not important box is finite or infinite.If we call universe is infinite I mean our universe is equal size as box.If I said finite universe it means our universe is a sphere in that box and there can be other spheres (parallel universes).So I mean If our universe is infinite then there will be no place to make a new unverse.But If our universe is finite then there will be a place. ##Ω_k=0## Means our universe is infinite so size will be equal as box and there will be no place to new universe.There one universe and its ours.

here's no way to know whether or not the universe is infinite. For example, we can't measure a curvature of identically zero: there will always be some error in our measurements, so we can never say that the curvature is perfectly flat. And even if we could, there are ways to write down a universe that is perfectly flat but is, nevertheless, finite (such as the toroidal universe).

This make sense

3. The quantum multiverse occupies the same space and time, but is separated into "worlds" that cannot communicate with one another.

I am talking about this situation. Parallel universe.If our universe is infinite then there will be no thing here a pic.If you look the pic I am askig If
##Ω_k=0## Means our universe is infinite so size will be equal as box and there will be no place to new universe.There one universe and its ours. Is this true

I know Chalnoth gave the answer but I want to clarify my question

 

[Chalnoth]

I am talking about this situation. Parallel universe.If our universe is infinite then there will be no thing here a pic.If you look the pic I am askig If
##Ω_k=0## Means our universe is infinite so size will be equal as box and there will be no place to new universe.There one universe and its ours. Is this true

In quantum mechanics, systems can be in a superposition of states. For an overly-simplified example of a system with two states:

[tex]\langle\Psi | = \langle 1| + \langle 2|[/tex]

This is analogous to the "both alive and dead" cat in the Schrodinger's cat thought experiment. If the two states have different energies, then the system will oscillate between them. Sometimes it'll mostly be in state ##\langle 1|##, sometimes it'll mostly be in state ##\langle 2|##. But if we ever perform an observation on this system that distinguishes between the two states, we'll only ever see one or the other.

Let's say that we've put this system into another system in state ##\langle A|##. The way we'd write this is:

[tex]\langle\Psi|\langle A| = \langle 1|\langle A| + \langle 2|\langle A|[/tex]

What this does is it changes the oscillation. Previously, we might go between the two states in microseconds. But now we've combined this state with another, and for the system to oscillate we have to wait until the oscillation of the 1-2 system is in sync with the A system's oscillations to see any oscillation. If the state ##\langle A|## is complex enough (say, hundred to thousands of atoms at room temperature), then the oscillation time will quickly grow to larger than the age of the universe. This means that this system, even though it is still in both states ##\langle 1|## and ##\langle 2|##, those two states can no longer interact with one another and each behaves almost entirely as if the other state doesn't exist.

This is the many worlds of quantum mechanics. The entire wavefunction occupies the same space, it's just that observers in some branches cannot observe what's going on in other branches.

 

[RyanH42]

This is the quantum multiverse idea.This idea and my Pic 2 (1) is same thing.or different ??

 

[Chalnoth]

That picture isn't specific enough for me to say.

 

[RyanH42]

 

[RyanH42]

There's many universes but we cannot contact with other universes

 

[Chuckstabler]

Wait, is there ANY evidence that there are "multiple parallel" universes that exist? Is it even a testable hypothesis?

 

[Chronos]

By most accounts the multiverse hypothesis is untestable in principle. That is not make it wrong. The better question. scientifically speaking, is whether any evidence exists to suggest the need for a multiverse. The multiverse hypothesis does not suffer a lack of motivation, just none sufficient to elevate it above the level of fringe science, IMO.

 

[Chalnoth]

Wait, is there ANY evidence that there are "multiple parallel" universes that exist? Is it even a testable hypothesis?

There are multiple different multiverse concepts, and their testability varies. In particular, most multiverse ideas are part of a larger framework, and that framework has other features that are very much testable.

The quantum multiverse, for example, is a direct consequence of wavefunction dynamics. Those wavefunction dynamics are testable and have been tested in a wide variety of experiments. It is possible to add assumptions to get rid of the extra "worlds", but there is no reason whatsoever to do that. So absent other evidence, the most reasonable conclusion is that the many worlds of quantum mechanics exist.

Edit: Also, I should mention that the decoherence procedure that leads to the many worlds has been observed.

 

[Quds Akbar]

Think of the universe as a balloon, it expands and you are a bug at the 2D surface (3D or 4D in our case but 2D to make it easier to imagine), it is infinite to you, because wherever you go, you will not find an edge, and as the balloon expands the distances between places will expand too. This idea is called the balloon analogy. And that means that for the balloon to expand extra dimensions are needed and from this point it gets a bit more complicated.

 

[Chalnoth]

Think of the universe as a balloon, it expands and you are a bug at the 2D surface (3D or 4D in our case but 2D to make it easier to imagine), it is infinite to you, because wherever you go, you will not find an edge, and as the balloon expands the distances between places will expand too. This idea is called the balloon analogy. And that means that for the balloon to expand extra dimensions are needed and from this point it gets a bit more complicated.

There's a difference between being infinite and having a horizon. What you've described is having a horizon. This isn't a feature of any expanding universe, by the way: it only appears due to the accelerated expansion. If there were no cosmological constant (or dark energy), then the expansion would continuously slow such that there would always be new galaxies to pass by if you were traveling at a high rate (well, until the universe got old enough that galaxies no longer existed, or the universe recollapsed).

 

[julcab12]

The quantum multiverse, for example, is a direct consequence of wavefunction dynamics. Those wavefunction dynamics are testable and have been tested in a wide variety of experiments. It is possible to add assumptions to get rid of the extra "worlds", but there is no reason whatsoever to do that. So absent other evidence, the most reasonable conclusion is that the many worlds of quantum mechanics exist.

We only have interpretation(indecisive) for quantum multiverse/worlds not evidence or at least not yet or it will never be. We can't really say much about. I can't deny that it is a direct assumption from some observable phenomenon in QM -- multiplicity(abstract). Exist is a strong word for QM's worlds -- perhaps silent?. I'm always advice to be very careful of the full observable ensemble. For instance, the Einstein cross. We can directly assume that quasars really do exist in multiple space at the same time and add multiple universes from direct interpretation standpoint. Luckily, we have lensing that produces this weird natural phenomenon and we have 1 quasar projected in multiple images when computed/realized. It's not about adding assumption to get rid of something we understand from one perspective but consider other interpretations and what it might lead.

 

[tom aaron]

There are multiple different multiverse concepts, and their testability varies. In particular, most multiverse ideas are part of a larger framework, and that framework has other features that are very much testable.

The quantum multiverse, for example, is a direct consequence of wavefunction dynamics. Those wavefunction dynamics are testable and have been tested in a wide variety of experiments. It is possible to add assumptions to get rid of the extra "worlds", but there is no reason whatsoever to do that. So absent other evidence, the most reasonable conclusion is that the many worlds of quantum mechanics exist.

Edit: Also, I should mention that the decoherence procedure that leads to the many worlds has been observed.

There are multiple different multiverse concepts, and their testability varies. In particular, most multiverse ideas are part of a larger framework, and that framework has other features that are very much testable.

The quantum multiverse, for example, is a direct consequence of wavefunction dynamics. Those wavefunction dynamics are testable and have been tested in a wide variety of experiments. It is possible to add assumptions to get rid of the extra "worlds", but there is no reason whatsoever to do that. So absent other evidence, the most reasonable conclusion is that the many worlds of quantum mechanics exist.

Edit: Also, I should mention that the decoherence procedure that leads to the many worlds has been observed.

Not really. The most reasonable approach is 'not' to add assumptions of extra 'worlds' but to try and explain the Universe through the known properties of matter and energy.

Yes, there may be multiple universes, parallel, etc. but at this stage there is no scientific basis to add them...science is about a testable hypothesis. Adding a multiverse theory is like adding a god variable...nice to speculate, philosophize about...but at the end of the day...all untestable and no more than great conversation disguised by pseudo-science gobbledygook that sounds important.

I enjoy reading about alternative universes but, being in the sciences, I have a file in my brain marked 'fun stuff'.

 

[Chalnoth]

We only have interpretation(indecisive) for quantum multiverse/worlds not evidence or at least not yet or it will never be. We can't really say much about.

Sure we can. We can test and measure the way quantum wavefunctions behave.

Not really. The most reasonable approach is 'not' to add assumptions of extra 'worlds' but to try and explain the Universe through the known properties of matter and energy.

Except the extra worlds of quantum mechanics are not an assumption. They're a consequence of the way that quantum wavefunctions behave. You get them automatically from quantum mechanics unless you add extra rules to quantum mechanics to get rid of them.

Without evidence there's no reason to add the extra rule or rules to quantum mechanics that gets rid of the other worlds.

 

[OCR]

Also, I should...

...make it a habit of citing your sources.

 

[Chalnoth]

You could ask for a source in a non-passive-aggressive way, you know.

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.77.4887

Unfortunately this one doesn't appear to be open-access.

 

[julcab12]

Sure we can. We can test and measure the way quantum wavefunctions behave.

... Evidence? Not quite. Common misconception on wavefunction. Some would argue that the quantum state is just a probability distribution others objectively real(Hilbert space). To be precise we are not certain on what were directly looking at (to some extent). The same reason i mentioned about Einsteins Cross, under any circumstances that we don't have any knowledge on lensing/SR we could easily fall for 'multiplicity enigma' surely because it looks that way and we could easily proposed Quasars being in places at the same time, assign some statistical distribution and remain valid. But we all know for a fact that the image is just a projection http://physics.stackexchange.com/qu...itational-lensing-account-for-einsteins-cross.

.. I find the idea and limit of SR to be convincing relating to CI interpretation on behavior of 'things'. For instance, "when objects travel the speed of light. It just happens that quantum uncertainty is more prevalent when it comes to particles traveling the speed of light, and it is negligible for objects with mass that don’t. Then if it is impossible to describe a particle accurately when it is traveling the speed of light using The Special Theory of Relativity and the theory itself breaks down, then if it was a truly accurate theory, it would mean that classical physics as we know it would break down. Say an object is traveling the speed of light at a constant speed. It is traveling at a constant speed so it assumes that it has a velocity of zero. Then from that frame everything else is traveling the speed of light. Everything contracts to zero. Then it would appear to the object that it is everywhere at once. Then it would seem like it had infinite speed, but from the other frame of reference it is only traveling at about 300,000 km/s. The theory breaks down. The two observers do not agree on a single state of reality. Then it just so happens that particles traveling the speed of light can be measured to travel at 300,000 km/s, and those particles can also have an action at a distance instantaneously through things like entanglement at the same time. Then the solution is simple. Both states of realities are actually happening at the same time, and as a direct consequence we observe this type of non-classical behavior. Particles that travel the speed of light can also have an action at a distance that is instantaneous at the same time.

After all. MWI will remain indecisive, interpretation(MW "I" --stands for anyways)..

 

[Chalnoth]

... Evidence? Not quite. Common misconception on wavefunction. Some would argue that the quantum state is just a probability distribution others objectively real(Hilbert space). To be precise we are not certain on what were directly looking at (to some extent). The same reason i mentioned about Einsteins Cross, under any circumstances that we don't have any knowledge on lensing/SR we could easily fall for 'multiplicity enigma' surely because it looks that way and we could easily proposed Quasars being in places at the same time, assign some statistical distribution and remain valid. But we all know for a fact that the image is just a projection http://physics.stackexchange.com/qu...itational-lensing-account-for-einsteins-cross.

.. I find the idea and limit of SR to be convincing relating to CI interpretation on behavior of 'things'. For instance, "when objects travel the speed of light. It just happens that quantum uncertainty is more prevalent when it comes to particles traveling the speed of light, and it is negligible for objects with mass that don’t. Then if it is impossible to describe a particle accurately when it is traveling the speed of light using The Special Theory of Relativity and the theory itself breaks down, then if it was a truly accurate theory, it would mean that classical physics as we know it would break down. Say an object is traveling the speed of light at a constant speed. It is traveling at a constant speed so it assumes that it has a velocity of zero. Then from that frame everything else is traveling the speed of light. Everything contracts to zero. Then it would appear to the object that it is everywhere at once. Then it would seem like it had infinite speed, but from the other frame of reference it is only traveling at about 300,000 km/s. The theory breaks down. The two observers do not agree on a single state of reality. Then it just so happens that particles traveling the speed of light can be measured to travel at 300,000 km/s, and those particles can also have an action at a distance instantaneously through things like entanglement at the same time. Then the solution is simple. Both states of realities are actually happening at the same time, and as a direct consequence we observe this type of non-classical behavior. Particles that travel the speed of light can also have an action at a distance that is instantaneous at the same time.

After all. MWI will remain indecisive, interpretation(MW "I" --stands for anyways)..

I think you've confused yourself here. This makes no sense. SR doors not have inconsistency problems, and quantum behavior isn't especially important at high velocities (it makes a much bigger difference at low velocities, especially low temperatures).

Anyway, I'll just leave this here:
http://www.preposterousuniverse.com...ion-of-quantum-mechanics-is-probably-correct/

 

[julcab12]

I think you've confused yourself here. This makes no sense. SR doors not have inconsistency problems, and quantum behavior isn't especially important at high velocities (it makes a much bigger difference at low velocities, especially low temperatures).
Anyway, I'll just leave this here:
http://www.preposterousuniverse.com...ion-of-quantum-mechanics-is-probably-correct/

...Carol has a strong opinion on MWI of which is not equally shared in the science community. https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics( Tabular comparison)

Well, going back.., we do have have 2 states for instance but the requirement for each state doesn't necessarily be in two separate states each having its own unique Hilbert spaces. It could also be simultaneity in time/observer dependent -- each state could not exist simultaneously at the same time(asumming time is not absolute like QFT -- where it uses both formalism exception of nonrelativistic QM/probabilistic). We would have interval dependent state and since our detectors(time/space affects the outcome/picture of an observer) are not absolute we won't be able to detect a very small time interval of a state. Hence, we are observing weird phenomenon/quantum behavior -- smeared/multiplicity on low scales using direct postulate of the observation. Staying true to SR -- which is compatible to Quantum Field Theory. It has the approximate effect on large/strong gravitational field

where spacetime is distorted following an image of multiple quasars. At first glance we could easily say it is 5 quasars due to direct detection but in reality it is just 1 when considering SR and lensing -- (which is more to do with formalism and variable treatment on Quantum postulates explained onwards). I always got the doubt the quantum picture is incomplete. This becomes effective solely on how to formulate QFT. We have a choice in making spatial coordinate into parameters(eventually multiple Hilbert spaces), or making time into an observable(satisfies unitarity). I didn't mention any inconsistencies but discontinuity of the formalism. Anyways going back..

If time becomes an operator, In relativistic theories, there is more than one notion of time. We can use the proper time τ of the particle (the time measured by a clock that moves with it) as the time parameter. The coordinate time T (the time measured by a stationary clock in an inertial frame) is then promoted to an operator. In the Heisenberg picture (where the state of the system is fixed, but the operators are functions of time that obey the classical equations of motion), we would have operators Xμ(τ), where X0=T. Relativistic quantum mechanics can indeed be developed along these lines, but it is surprisingly complicated to do so. (The many times are the problem; any monotonic function of τ is just as good a candidate as τ itself for the proper time, and this infinite redundancy of descriptions must be understood and accounted for.) The difference come from the interpretation of the formalisms which affects generalization directions. Take for example, Xμ(τ), why not consider adding some more parameters? Then we would have, for example, Xμ(σ,τ). Classically, this would give us a continuous family of worldlines, what we might call a worldsheet, and so Xμ(σ,τ) -- string picture. The other choice is demoting position to a label or operator. Consider assigning an operator x in space; call these operators ϕ(x). A set of operators like this is called a quantum field. In the Heisenberg picture, the operators are also time dependent: ϕ(x,t)=eiHt/ℏϕ(x,0)e−iHt/ℏ . Thus, both position and (in the Heisenberg picture) time are now labels on operators; neither is itself the eigenvalue of an operator. So, now we have two different approaches to relativistic quantum theory, approaches that might, in principle, yield different results. This, however, is not the case: it turns out that any relativistic quantum physics that can be treated in one formalism can also be treated in the other. Which we use is a matter of convenience and taste. And, quantum field theory, the formalism in which position and time are both labels on operators, is much more convenient and efficient for most problems but could be said the other way around.

Why should assuming absolute time(consequent generalization of multiple unique states-- multiverse/manyworlds anything with many on it lol) or some cutoff and/or idealization treatment on time be the only alternative? BTW I'm not saying macro weirdness/phenomenon(Einstien cross) is on par with quantum weirdness. I'm only stating a critical aspect of spacetime/ problem with taking a strong commitment to direct picture of an observation and how distortions of spacetime could produces weird phenomenon only to be known that is not to be the case..

 

[Chalnoth]

...Carol has a strong opinion on MWI of which is not equally shared in the science community. https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics( Tabular comparison)

A number of these reduce to MWI, but just use different words for the same things. The rest modify quantum mechanics in ways that are not suggested by any evidence, and are thus unlikely.

But really, this state of affairs is positively embarrassing for physics. I think it's only been maintained because a) The idea of multiple worlds makes a lot of people uncomfortable, and b) It is only very recently that any experimental or engineering problems have required thinking carefully about wavefunction collapse. But because understanding how and why wavefunctions collapse has become important for quantum computing, it makes sense to me that this issue has been revived relatively recently (to build a quantum computer, its useful to prevent the wavefunction from collapsing for as long as possible).

Well, going back.., we do have have 2 states for instance but the requirement for each state doesn't necessarily be in two separate states each having its own unique Hilbert spaces. It could also be simultaneity in time/observer dependent -- each state could not exist simultaneously at the same time(asumming time is not absolute like QFT -- where it uses both formalism exception of nonrelativistic QM/probabilistic).

It could be a lot of things. But there's no reason to add new dynamics to quantum mechanics when the Schroedinger equation explains the (non-relativistic) experiments just fine, especially as those new dynamics (usually) don't change the expected experimental outcomes.

There are some semi-decent arguments against MWI. Specifically related to the interpretation of probability in the model. But with the recent work of Deutsch and others, I've become convinced that that problem is largely solved. If it were impossible to derive a probability rule from MWI, we might well need some of those other assumptions to make the theory work. What I find sad is that I almost never hear any of the more decent arguments against the model. All I ever do hear are specious attacks, such as the idea that the theory is complex because of the many worlds.

 

[Finny]

RyanH: "Think a box, box is space time.Its not important box is finite or infinite.If we call universe is infinite I mean our universe is equal size as box. If I said finite universe it means our universe is a sphere in that box and there can be other spheres (parallel universes). So I mean If our universe is infinite then there will be no place to make a new unverse..."

Why just a box?? That's a way too simplified view of what a 'universe' might really be like. I don't personally know how to 'picture' a universe, but for the reasons below, a sphere inside a box does not lead to valid perspectives. If you start off with an incorrect model, you'll likely draw incorrect conclusions.

Consider this for starters: YOUR testable universe, one in which you you can make measurements and observations, is limited to your past lightcone. Light signals must be able to reach you. 'My universe', in a galaxy far far away, might be completely different and we may never have a causal connection to enable us compare notes. Whose to confirm or deny that's 'a universe' or 'two'.

Here are some other thoughts about 'parallel' universes:

The Elegant Universe, Brian Greene
"The special theory of relativity declares the laws of physics appear identical to all observers undergoing constant velocity motion. Since there is no difference between an accelerated vantage point without a gravitational field and a non accelerated vantage point with a gravitational field, all observers regardless of their state of motion may proclaim they are stationary and the rest of the world is moving by them so long as they include a suitable gravitational field..."

[Hmm, so gravity and acceleration are linked in some way. Even coincident observers may make different valid observations. Are the universes of an inertial observer and an adjacent [coincident] accelerating observer 'identical"...depends how you want to define things. Those two will measure different particle counts and temperatures: See Unruh effect They seem to have different vacuum states. How can that be in 'one universe'. Again, depends how you want to define things.]

"...uniquely-defined particle states do not exist in general, in QFT on a curved spacetime. {Accelerating observers will not agree on particle counts with inertial observers.}
Do you even need 'volume'..and what does that mean??

Holographic Principle: The Black Hole War Chapter 18 Leonard Susskind
EVERYTHING INSIDE A REGION OF SPACE CAN BE DESCRIBED BY INFORMATION BITS ON THE BOUNDARY.

The maximum amount of information that can be stored in any region of space is determined by the area of the boundary enclosing the space rather than the enclosed volume. All information is stored on the boundary of space. Where a particular bit of information is located does not have a unique answer. At each level of space, everything enclosed may be described as a holographic image but when we go looking for the hologram it is always out at the next level.
String theory mathematics places every bit of information at the outer edges of the universe or infinity if the universe is unbounded. ...
Similar idea, different perspective:

Fabric of the Cosmos, Greene, p 481-485
"..If the maximum entropy in any given region of space is proportional to the region’s surface area rather than its volume, perhaps the fundamental degrees of freedom that give rise to that disorder (entropy) reside on the surface and not within the volume. Maybe all the physical processes of the universe take place on a thin distant surface that surrounds us. All we experience is merely a projection of those distant processes from a bounding surface.

Or maybe it’s better to think of holography as articulating a kind of duality between the more familiar description of fundamental laws here in the four dimensional bulk (which our intuition and perceptions suggests) and an unfamiliar description in which fundamental physics takes place on some kind of boundary of the universe.
Juan Maldacena found a hypothetical realization of holography within string theory. He showed a particular quantum theory without gravity is a translation of – is indistinguishable from - another quantum theory that includes gravity but is formulated with one more space dimension.
Not only can the size and shape of spacetime change in translation from one formulation to another equivalent form but the number of space dimensions can change too. So it seems the form of spacetime, the number of dimensions for example, is an adorning detail that can change from one formulation to another rather than being a fundamental constituent of reality. ..."

Lots to think about. Good luck.

 

[OCR]

Lots to think about.

Lots to listen to, also ...

Say what you want, but Leonard Susskind is an interesting fellow ...

All from YouTube, some good, some not so...

Holographic Principle:

The Black Hole War:

 

[tom aaron]

Lots to listen to, also ...

Say what you want, but Leonard Susskind is an interesting fellow ...

All from YouTube, some good, some not so...

Holographic Principle:

The Black Hole War:

I'm never sure what to think of Leonard. I find him fascinating at one level but then catch myself wondering if he isn't off on some tangent of his own making. He can be funny but, again, a bit self absorbed complaining about some Power Point set up or not having a blackboard at his disposal.

Most of these personalities are good at explaining things in understandable terms but I have the feeling they really need hours to answer the simplest of questions from the audience. Just about every sentence in theoretical physics needs to be accompanied by a dozen 'if' or 'perhaps' type qualifications.

I do like the way Susskind isn't afraid to trot out the math for the audience. He doesn't dumb things down as much as some physicists to silly analogies that may sound informative but actually can be misleading.

 

[Chronos]

Susskind offers more than a few silly argument in physics.

 

[julcab12]

A number of these reduce to MWI, but just use different words for the same things. The rest modify quantum mechanics in ways that are not suggested by any evidence, and are thus unlikely.

But really, this state of affairs is positively embarrassing for physics. I think it's only been maintained because a) The idea of multiple worlds makes a lot of people uncomfortable, and b) It is only very recently that any experimental or engineering problems have required thinking carefully about wavefunction collapse. But because understanding how and why wavefunctions collapse has become important for quantum computing, it makes sense to me that this issue has been revived relatively recently (to build a quantum computer, its useful to prevent the wavefunction from collapsing for as long as possible).

... I hope it's that simple. There are 3 general characteristic of QM's interpretation; multiplicity, holographic, singular/unitarty. QFT explains a system with all those 3 and gives pretty much the same result and goes beyond also. Multiplicity is a direct consequence of the wave and renormalized using wavefunction. We can detect strange behavior and that's about it but that doesn't mean it is all there is(like most theory does -- GR and SR regardless of Non-thingy). We try to make sense out of it by applying the formalism of wavefunction and obeying postulates. Eventually we get expected satisfactory result. The same could be said to QFT with a bit of modification (no adds) -- that is instead of particle/wave it is replaced by fields or field operators which replaces the huge constraints of having each worlds to single huge hilbert space arguably infinite -- including the fact that it is compatible to SR. The intuitive thing about QFT is it does work without position operator which is the main gist for having multiple things at once. The reason i raised the issue on time here simply because it affects our perception of 'observer --/observation' being not absolute which follows perhaps things might not appear directly. So i said, its silent for now or indecisive.. It's the same motivation that gives other interpretations each with their own merits not just because its unsettling. Anyways, all of this are math that works in both ways. I think it is a healthy suspicion and motivation.

 

[PeterDonis]

Say an object is traveling the speed of light at a constant speed. It is traveling at a constant speed so it assumes that it has a velocity of zero. Then from that frame everything else is traveling the speed of light. Everything contracts to zero. Then it would appear to the object that it is everywhere at once.

This is not correct. You are assuming that you can construct a reference frame in which a lightlike object (one moving at the speed of light) is at rest. That assumption is false.

 

[julcab12]

This is not correct. You are assuming that you can construct a reference frame in which a lightlike object (one moving at the speed of light) is at rest. That assumption is false.

..

Of course. SR won't allow that since it is C; Where E becomes undefined and Mo -- rest mass becomes zero. We conclude that photon has no rest frame thus C becomes the same in all inertial frame Anyways. I just imagined what would it look like having zero time or maybe non zero, infinite time dilation and length contraction--gamma. In the case of microscale no well defined time. Would it had any visual effect on microscale for instance like how GR lensing effects causing image to appear multiple?

 

[PeterDonis]

it is C; Where E becomes undefined and Mo -- rest mass becomes zero.

The energy of a photon is not undefined. The general formula ##E^2 = p^2 c^2 + m^2 c^4## applies equally well to photons, with ##m = 0##, and to timelike objects, with ##m > 0##. If you are looking at the formula ##E = \gamma m c^2##, that formula is not applicable to photons, so the fact that it is undefined for ##v = c## is irrelevant.

I just imagined what would it look like having zero time or maybe non zero, infinite time dilation and length contraction--gamma. In the case of microscale no well defined time.

I'm not sure what this means. SR doesn't suddenly stop working for objects like photons that move at ##c##, and QFT doesn't suddenly stop being based on the spacetime of SR for photons. If you are talking about proposed quantum gravity theories in which spacetime is no longer fundamental but emerges from something else, that still doesn't change how spacetime behaves once it emerges. So I don't see the point of imagining what you are trying to imagine.

 

[julcab12]

The energy of a photon is not undefined. The general formula E2=p2c2+m2c4E^2 = p^2 c^2 + m^2 c^4 applies equally well to photons, with m=0m = 0, and to timelike objects, with m>0m > 0. If you are looking at the formula E=γmc2E = \gamma m c^2, that formula is not applicable to photons, so the fact that it is undefined for v=cv = c is irrelevant.

Ah, ok. Maybe that's the cause of my confusion. Since photon (photoelectric effect) rest mass of the photon is zero while it has inertial mass -- nothing with rest mass can travel at C(pythagorean). A photon clocks happens to travel along paths of zero spacetime interval. At C, the math breaks down 0/0. Well we can say 2 things about it. Either, You imagine it as zero(strongly implied) second or you could simply say that the equations of SR breaks down irretrievably at relative speeds of C. If that's the case. Would it be possible to say that lengths goes to undefined(lengths get shorter and shorter doesn't mean they get to zero)? A massless particle has no well defined distance or frozen in time. They appear in all places or hidden(we just don't know) until it interacts with something (like higgs field and by virtue of motion or momentum) and time deviates in that process and can be detected as particle. We can't say anything meaningful from a photons perspective except to speculate under its limit time > 0 non zero. I just imagined that 'time' intervals created by interactions creates that nonlocal picture or at least has something to do with nonlocality and why particle behave in peculiar way. Generally, I was imagining it to be this way.; At time zero(assuming, let's just say zero interaction approx). A 'thing' single particle could appear in all places at once/flat/spread out indefinitely-- (normally it will appear FLAT ) and when it interact with something, 'time' starts to move and particle will gradually collapse from its spread state to a local state. In MWI the spreading out is composed of unique infinite states; that can only be possible if time is absolute but why?. In what I am imagining(regardless of me being relationalist); time is an step state and 'relative' to the amplitude/field not spread in unique infinite states having its own time. The higher(time slows as it get higher) the peak the greater the probability of a particle be detected. They only appear 'as if' (IMO) they are in places or spread out because time is jittery to them and we get that picture (mulitplicity) until it is computed as we get obvious singular result like for example -- Einstein cross. It appears in multiple because spacetime is distorted having projected as 5 images by our detector until computed.

 

[PeterDonis]

At C, the math breaks down 0/0.

No. At c some of the math breaks down 0/0. But not all of it. And we can describe photons perfectly well using the math that does not break down at c.

All the rest of your post appears to be based on this misconception you have that all the math breaks down at c. It doesn't.

 

[julcab12]

But not all of it. And we can describe photons perfectly well using the math that does not break down at c.
.

Sorry for the late reply. Yes. I'm aware of that but i haven't gotten much on the detail (introductory). The rest of my post is from standard QFT concerning on the interpretation of time. Notice that i didn't add or change anything. It's just how time is represented in the equation. My main motivation comes from this paper http://lanl.arxiv.org/pdf/1309.0400v2.pdf which is discussed in QM forum with regards to photon without having any trajectories. According to the paper-- "To understand the main idea, let us first reformulate the problem as follows. Suppose that one wants to interpret |ψ| 2 as probability density conserved in time. But the theory of relativity asserts that the time coordinate is not unique. So the question is: which time?". According to the paper, Time is a spacelike hypersurface of constant time and the time is experienced by the particle starting at x^0 trajectory Or the proper time is associated with particle trajectories. For obvious reasons, a massless particle is always at time 0(standard convention). Details shown 1.2 pg 5 onward). We can therefore say that a particle is spread out at time 0. For instance, Photon (boson field). I was imagining this way. Instead of particle. It is just fields. A true field (boson field) is global @ time 0 and the hypersurface is flat in a hypothetical absence of any excitation or interaction. There are no particle just fields. Particle is created from interactions and excitation of the field. I imagined a 'field to particle' transformation not a particle in a field. The information is spread out/hypersurface and it doesn't travel since distance is contracted to 0 or maybe infinite(natural consequence of SR). From a psuedo perspective of a 0 time field -- entanglement. What does it have to do with particle in superposition? Distance/time no longer applies. Interactions cause the field to deviate to a particle and time emerges. Label state(QFT) is not a multi state (MWI -QM). We can just have fields(minimal structure LQG) and energy in hilbert space(probably infinite).https://www.physicsforums.com/threads/some-sins-in-physics-didactics-comments.812627
https://www.physicsforums.com/threads/comments-how-fundamental-is-the-arrow-of-time.819255/

 

[PeterDonis]

The rest of my post is from standard QFT concerning on the interpretation of time.

No, it isn't; it's your personal (mis)interpretation of QFT. QFT is perfectly consistent with SR and with how SR handles null worldlines and particles with zero rest mass that move on null worldlines. The only complication with QFT is that massless particles, like the photon, only move on null worldlines when they are on shell; off-shell photons can move on timelike or even spacelike worldlines. (Similarly, off shell particles with nonzero rest mass can move on null or spacelike worldlines.)

My main motivation comes from this paper http://lanl.arxiv.org/pdf/1309.0400v2.pdf

This paper isn't about QFT; it's about "relativistic Bohmian mechanics". They're not the same thing.