Is time travel possible based on theory?

[Write4U]

Then if there exist a system C whose measurements are sometimes a and sometimes b, one says that C in a state in superposition of the states A and B.

IMO,
a state of superposition is always theoretical and cannot ever be the result of the collapsed state. That's when the superposition gets sorted out in reality as either A or B, never both at the same time.

Superposition is a "potential", which implies a possible choice between two opposing preliminary states.
potential is defined as: "That which may become reality"

 

[Michael 345]

Superposition

From my understanding it is not a single component you are trying to observe

It is a mix of components and when observations are made you see one OR the other

Did I get that right?



Current book extracted from the 500 I downloaded
Started reading last night

Looks good

 

[Write4U]

It is a mix of components and when observations are made you see one OR the other
Did I get that right?

I think so.
As I understand it, the observation is what collapses the wave function and resolves the superposition into one state or the other.

p.s. I have not yet watched this but may be a good companion to the book.

What is Relativity? An Introduction to Einstein's Theory with Dr. Jeffrey Bennett

 

[Michael 345]

I think so.
As I understand it, the observation is what collapses the wave function and resolves the superposition into one state or the other.

So Schrodinger’s cat works if you have both a live AND dead cat in the box, and the alive/dead cat pair oscillate between being in the box or somewhere else

Opening the box stops the oscillation and you see one OR the other

Thought bubble

If you flap the lid fast enough would your observations finish up 50/50 alive/dead?

 

[Write4U]

So Schrodinger’s cat works if you have both a live AND dead cat in the box, and the alive/dead cat pair oscillate between being in the box or somewhere else

LOL, I think you have a cat in the box which may be alive or dead. The superposed states are theoretical states. It is a thought experiment.

Let us not forget Schrodinger posed the problem to show the inherent contradiction.

In quantum theory, quantum particles can exist in a superposition of states at the same time and collapse down to a single state upon interaction with other particles. Some scientists at the time that quantum theory was being developed (1930's) drifted from science into the realm of philosophy, and stated that quantum particles only collapse to a single state when viewed by a conscious observer. Schrodinger found this concept absurd and devised his thought experiment to make plain the absurd yet logical outcome of such claims.

https://wtamu.edu/~cbaird/sq/2013/07/30/what-did-schrodingers-cat-experiment-prove/

 

[Write4U]

Suppose the cat died but we are traveling back in time? Will the the cat magically revive at some point, return to a state of superposition?

 

[Michael 345]

Suppose the cat died but we are traveling back in time? Will the the cat magically revive at some point, return to a state of superposition?

Doubtful

What is Relativity? An Introduction to Einstein's Theory with Dr. Jeffrey Bennett

Watched the video. Put it up on the 65" TV, good quality. Fell asleep last ¼ hour

Not the best presenter, but from the bit of the book have read, a better author. Regardless thanks for the link

Got couple of gems from the video. One was the 50 year round trip at 99.9% speed of light to Alpha Centauri, the Earth twin ages 50, the astronaut 7 years

Unfortunately not spelled out HOW. Some mention of the speed of light being the absolute, also mentioned was the fabric of space-time being curved though which the planets roll as explaination of gravity

Time to hit the books again

Cheers

Coffee moment

 

[pluto2]

Time travel is probably only possible in a science fiction world or in a fantasy world.

But I have to tell you that I'd choose a science fiction world like Star Trek or Stargate over the world we live in right now at any time because this world very much sucks and I don't like it because it's crazy.

 

[Write4U]

Time travel is probably only possible in a science fiction world or in a fantasy world.

But I have to tell you that I'd choose a science fiction world like Star Trek or Stargate over the world we live in right now at any time because this world very much sucks and I don't like it because it's crazy.

And what is it about Star Trek and Stargate that attracts you? Kirk and Spock cleaning up crazy situations on different planets instead of different neighborhoods on earth?

Not much different, just on a larger scale!

 

[pluto2]

And what is it about Star Trek and Stargate that attracts you? Kirk and Spock cleaning up crazy situations on different planets instead of different neighborhoods on earth?

Not much different, just on a larger scale!

I was just kidding. In the movies anything is possible.

But time travel is actually not possible under any law of physics that we know of. And physics and only physics dictates what is possible or not in the very end.

 

[QuarkHead]

IMO,

Fortunately for science, opinions do not count - only observations and conclusions drawn from them do.

a state of superposition is always theoretical and cannot ever be the result of the collapsed state.

Agreed, superposition is not the RESULT of a collapsed state. One can argue (like Niels Bohr) that, given a state can be represented as a wave function, then measurement trivializes the wave function function so that it is everywhere except at a single point in state space

That's when the superposition gets sorted out in reality as either A or B, never both at the same time.

Whose "reality"? Yours or observational science's?

potential is defined as: "That which may become reality"

You are privileged to have an insight into "reality" without observation!!

 

[Write4U]

Fortunately for science, opinions do not count - only observations and conclusions drawn from them do.

QuarkHead, that's just a meaningless knee-jerk response. Opinions don't count? How about knowledgeable opinions? If the opinion is in agreement with "official scientific concensus", it still doesn't count anyway?

Opinion, noun.
1 A view or judgement formed about something, not necessarily based on fact or knowledge.

• ‘that, in my opinion, is right’
  ‘the area's residents share vociferous opinions about the future’
  1. 1.1mass noun The beliefs or views of a group or majority of people.
     
     ‘the changing climate of opinion’
     
     
  2. 1.2An estimation of the quality or worth of someone or something.
     
     ‘I had a higher opinion of myself than I deserved’
• 2A statement of advice by an expert on a professional matter.
  
  ‘if in doubt, get a second opinion’
  1. 2.1Law A barrister's advice on the merits of a case.
     
     ‘the solicitor took counsel's opinion’
     
     
  2. 2.2Law A formal statement of reasons for a judgement given.
     
     ‘a dissenting opinion adjudged that the government had the right to protect ‘the symbolic value of the flag’’

W4U said,
a state of superposition is always theoretical and cannot ever be the result of the collapsed state.

QH said,

Agreed, superposition is not the RESULT of a collapsed state. One can argue (like Niels Bohr) that, given a state can be represented as a wave function, then measurement trivializes the wave function function so that it is everywhere except at a single point in state space

W4U said,
That's when the superposition gets sorted out in reality as either A or B, never both at the same time.

QH said, Whose "reality"? Yours or observational science's?

W4U said,
potential is defined as: "That which may become reality"

QH said,
You are privileged to have an insight into "reality" without observation!!

And it is your observation that I made those statements without observation? Your observation is science and mine is pure speculation?
AND HOW DO YOU KNOW THAT! SPECULATION?

Definition of potential
1: existing in possibility : capable of development into actuality

https://www.merriam-webster.com/dictionary/potential

Potential: "that which may become reality", are we clear on this? Or do you have the privilege to have insight to someone's "knowledge" without observation, which according to you is a nono, tsk,tsk,tsk.

If you need clarification on anything, just ask, and I'll explain, ok.

 

[QuarkHead]

If you need clarification on anything, just ask, and I'll explain, ok.

I certainly shall, thank you. How about you start with Quantum Electrodynamics, which is causing me some difficulty - or rather the mathematics is. Please clarify

 

[Write4U]

I certainly shall, thank you. How about you start with Quantum Electrodynamics, which is causing me some difficulty - or rather the mathematics is. Please clarify

You mean QED is an incomplete theory which requires greater explanation?
Isn't that precious. I offer to explain anything I said which is not instantly clear and you come back with a question which I did not address to begin with and which apparently no one can answer, right?

That's a disingenuous question, not posed in good faith.

 

[QuarkHead]

You mean QED is an incomplete theory which requires greater explanation?
.

Ah now, you flatter me. That I am struggling with the mathematics of Quantum Electrodynamics hardly seems to suggest it is an incomplete theory - I am far from being that clever!

 

[Write4U]

Ah now, you flatter me. That I am struggling with the mathematics of Quantum Electrodynamics hardly seems to suggest it is an incomplete theory - I am far from being that clever!

Ahh. Well my knowledge of mathematics extends only to advanced bookkeeping, so I'm afraid I can be of no assistance in the maths of QED... I am happy when I understand the concepts behind a theory, let alone the maths.

I do have understanding of the "mathematical function". That helps when observing the Natural Order of the universe.

I am struggling with the concepts (and maths) of Bohmian Mechanics which, like QED, also resolves the conflict between QM and GR. It does away with the notion of the particle/wave duality, which is the great sticking point.

Are QED and Bohmian Mechanics in competition or are there common denominators which may offer compatibility?

 

[Write4U]

W4U said,
That's when the superposition gets sorted out in reality as either A or B, never both at the same time.

QH said,
Whose "reality"? Yours or observational science's?

Observational science , of course. My observational science is no different than anyone else's.

Better question would be, what happens in a multiverse? Do different universes share the same quantum event? Can A be B in a different universe? If so, are the events in each universe related at all or occur totally independently from each other?

And what are the Potential Implications of that "perspective".....

I have empathy with this presenter and his perspective on the physical world.

 

[phyti]

If a particle has 2 possible states, a or b, you don't know which one is current unless you perform an observation. My simple analogy of superposition is a coin flipped into the air. While in motion it can be considered in a H and Y state. When it comes to rest, an observation reveals either H or T.

In the case of Schrodinger's cat, the uncertainty is not with the cat, but the decay of the radioactive material.

Both cases tend to reveal the 'wave function' as a lack of knowledge about a system, and not about the system itself.

With time defined as a dimension, it's not surprising that someone will ask, can we go there.

 

[TheFrogger]

Michael345, if time does not exist, then in the following example how is it possible to travel from one to two:

2-----------
xxxxxx/
xxxxx/
xxxx/
xxx/
xx/
x/
/
-------1

?

A human being IS time: it is within us. Time is subjective, and travelling thus means that by traversing time, YOU will discover what YOU have done; it doesn't mean an absence of action results in an action. If you do not do something, it will not happen.

 

[TheFrogger]

Of course you have proven that time is objective, haven't you?