Problem of time: No-time theories?

[Schreiberdk]

Hi there PF :)

Are there currently any physical theories trying to get rid of time, since time is not actually a measureable quantity
(one measures the frequency of a quartz crystal in a wristwatch, not time, one measures the frequency of a pendulum in a tower clock, not time, one measure the frequency of radioactive decay in atomic clocks, not time)?

\\Schreiber

 

[Fra]

You may find this interesting.

On the reality of time and the evolution of laws
Speaker(s): Lee Smolin
Abstract: There are a number of arguments in the philosophical, physical and cosmological literatures for the thesis that time is not fundamental to the description of nature. According to this view, time should be only an approximate notion which emerges from a more fundamental, timeless description only in certain limiting approximations. My first task is to review these arguments and explain why they fail. I will then examine the opposite view, which is that time and change are fundamental and, indeed, are perhaps the only aspects of reality that are not emergent from a more fundamental, microscopic description. The argument involves several aspects of contemporary physics and cosmology including 1) the problem of the landscape of string theory, 2) cosmological inflation and the problem of initial conditions, 3) the interpretation of the “wavefunction of the universe,” and the problem of what is an observable in classical and quantum general relativity. It also involves issues in the foundations of mathematics and the issue of the proper understanding of the role of mathematics in physics. The view that time is real and not emergent is, I will argue, supported by considerations arising from all these issues It leads finally to a need for a notion of law in cosmology which replaces the freedom to choose initial conditions with a notion of laws evolving in time. The arguments presented here have been developed in collaboration with Roberto Mangabeira Unger .
-- http://pirsa.org/08100049/

/Fredrik

 

[tom.stoer]

http://arxiv.org/abs/0903.3832
"Forget time"
Authors: Carlo Rovelli
(Submitted on 23 Mar 2009 (v1), last revised 27 Mar 2009 (this version, v3))
Abstract: Following a line of research that I have developed for several years, I argue that the best strategy for understanding quantum gravity is to build a picture of the physical world where the notion of time plays no role. I summarize here this point of view, explaining why I think that in a fundamental description of nature we must "forget time", and how this can be done in the classical and in the quantum theory. The idea is to develop a formalism that treats dependent and independent variables on the same footing. In short, I propose to interpret mechanics as a theory of relations between variables, rather than the theory of the evolution of variables in time.

 

[James A. Putnam]

All empirical evidence arrives as patterns in changes of velocity. These changes are delivered incrementally by photons. The information supplied by each photon consists of an increment of time and an increment of distance. The point is that both of these measurements have to do with the motion of objects. Neither space nor time are available for experimentation. Neither change their velocities. Neither can be shown to have velocities. So, the information delivered via photons is about particles. There are measurements of distance and duration made in both time and space; but, those measurements are always about distance between objects and the duration of physical events.

James

 

[atyy]

http://arxiv.org/abs/0711.0757
Universal quantum mechanics
Steven B. Giddings
"There is no intrinsic notion of time or history in this description. Such notions may emerge for certain UQM theories in certain states."

 

[S.Daedalus]

There's also Julian Barbour's ideas on time-less physics as derived from a special formulation of the action principle; http://www.platonia.com/nature_of_time_essay.pdf" that won the FQXi institute contest on the topic of the nature of time.

 

[Fra]

The reason I posted the Smolin link is because it contrasts the other timeless and "forget time" views (Rovelli, Juilian etc).

Both sides in fact have somewhat plausible arguments. I suggest that one constructive task is to see the good arguments of both sides; then try to come up with a conclusion. Is one wrong and one right, or do we need a new way to understnad this?

Smolins talk is good, as it acknowledges _when_ the timeless law formulation (that he also explicitly admits was most cleanly phrased by people such as Julian Barbour), and when it doesn't; and what comes next?

/Fredrik

 

[eiyaz]

Hi there PF :)

Are there currently any physical theories trying to get rid of time, since time is not actually a measureable quantity
(one measures the frequency of a quartz crystal in a wristwatch, not time, one measures the frequency of a pendulum in a tower clock, not time, one measure the frequency of radioactive decay in atomic clocks, not time)?

\\Schreiber

Is this suggesting that time doesn't exist and that time does not flow, but is merely a human perception?

Is this generally embraced in physics? I was under the impression that the fourth dimension is time and that time does flow, hence the arrow of time. Also these theories would suggest that time travel is impossible correct?

 

[gregorygregg1]

Is this suggesting that time doesn't exist and that time does not flow, but is merely a human perception?

Is this generally embraced in physics? I was under the impression that the fourth dimension is time and that time does flow, hence the arrow of time. Also these theories would suggest that time travel is impossible correct?

In regard to your question, I have three additional questions regarding time:
1. If, as Einstein suggested, time stops at the speed of light, does that mean that at the speed of light it would always be now, and like a photograph, nothing would change?

2. If so, does this mean that now travels at the speed of light, and since we are only aware of now, that awareness happens at the speed of light?

3. Is our perception of time caused by the difference between the speed of our awareness and the speed of mater as recorded by our memories, since mater cannot travel at light speed?

 

[Prawn]

I found this unanswered topic interesting and my apologies for bringing it back but due to the recent news articles regarding time and time travel I felt it relevant and hoped that it warranted further discussion.

In answer to your questions in my opinion and hopefully it makes sense to you, time itself would not stop at the speed of light. Our similar perception of space/time exists as we share a similar position within it. Each of us traveling at the same speed under the same gravity so from this we can share in a similar interpretation of what time is and how it flows from or vantage point.

For talking sakes however let's say I escaped Earth traveling at 99% the speed of light to an observer on Earth if they could watch me I would appear be moving extremely slow almost frozen but not quite while still hurtling through space/time. I however would not know this. I would think that I was functioning as normal but in reality the signals from my brain, assuming they travel at the speed of light, would be traveling at 1% of their normal speed.

Upon reaching the speed of light I would have no awareness of time at all because at a molecular level I would have come to a complete stop those electrical signals would be moving at 0% therefore i would have no notion of time. I would however still be traveling through space/time but would not become aware of that until I decelerated below the light barrier.

I don't know if that counts as time travel because theoretically I could travel at the speed, the speed of light forever and not be aware of it until I slowed.

 

[bapowell]

For talking sakes however let's say I escaped Earth traveling at 99% the speed of light to an observer on Earth if they could watch me I would appear be moving extremely slow almost frozen but not quite while still hurtling through space/time. I however would not know this. I would think that I was functioning as normal but in reality the signals from my brain, assuming they travel at the speed of light, would be traveling at 1% of their normal speed.

Upon reaching the speed of light I would have no awareness of time at all because at a molecular level I would have come to a complete stop those electrical signals would be moving at 0% therefore i would have no notion of time. I would however still be traveling through space/time but would not become aware of that until I decelerated below the light barrier.

I don't know if that counts as time travel because theoretically I could travel at the speed, the speed of light forever and not be aware of it until I slowed.

Very little of any of this is physically correct.

 

[Prawn]

I understand that it is not physically correct as Physics states that time would stop, i would have no dimentions, and my mass would be infinit. I was attempting to discuss the subjective nature of time perception.

 

[bapowell]

But it's physically meaningless to take the limit $v \rightarrow c$ in special relativity.

 

[Naty1]

It leads finally to a need for a notion of law in cosmology which replaces the freedom to choose initial conditions with a notion of laws evolving in time.

What an interesting concept ! and Thanks for posting research paper links.

 

[Fra]

What an interesting concept ! and Thanks for posting research paper links.

I'm glad you find it interesting. Unfortunately, there really ISn't much fleshed out publications in this direction. So there is a huge research gap to be filled in, I hope to see more in this direction in the future.

/Fredrik