Time Travel Simulated by Australian Physicists

Physicists at University of Queensland, Australia have simulated time travel using particles of light. The researchers achieved this by simulating the behavior of a single piece of light–a particle of energy–traveling on a closed timelike curve (CTC)–a closed path in space-time. The work may help to understand the longstanding problem of how time-travel could be possible in the quantum world and how the theory of quantum mechanics might change in the presence of closed timelike curves.

Time Travel Simulated by Australian Physicists

In the study, the research team simulated the behavior of a single photon that travels through a wormhole and interacts with its older self. This was achieved, PhD student Martin Ringbauer told The Speaker, by making use of a mathematical equivalence between two cases. In the first case, photon 1 “travels trough a wormhole into the past, then interacts with its older version.” In the second case, photon 2 “travels through normal space-time, but interacts with another photon that is trapped inside a CTC forever” (as shown in the illustration at top of the article). “Using the (fictitious second case) and simulating the behavior of photon 2, we were able to study the more relevant case 1,” said Ringbauer.

“We used single photons to do this,” said UQ Physics Professor Tim Ralph, “but the time-travel was simulated by using a second photon to play the part of the past incarnation of the time travelling photon.”

In my opinion, this is an interesting study, and it is good to see some headway in such fields. I don't have much to say, as i'm still processing much of what i have read (lol).

In the article, the scientists behind the project proceed to comment on matters regarding time travel and the theories of general relativity and quantum mechanics. Needless to say, it makes for some interesting reading.

I don't know what to say really ......

Other than ......freaking awesome!

I can't really math ...so all this is beyond my comprehension for the Time being ..

However I hope I am alive to see the day its possible..

Great thread !

S+F

There is a maxim that says-once time travel is discovered it will have existed for all time-the logic of this seems irrefutable to me, the fact you can't put genies back into bottles etc...however...who knows?

a reply to: daaskapital

Calm down, it's not real time travel. It's only in the quantum world.

Also worth noting:

Part of the reason time travel could be freed from such paradoxes in the quantum world is that the properties of quantum particles are “fuzzy” and “uncertain,” and therefore there is “wriggle room” to avoid inconsistencies in such situations, according to Professor Ralph.

They are basically saying that because some things in quantum mechanics are still less understood than classical physics, they have room to fudge the numbers to make their theory fit against the math.

It's very compelling, and a nice thought experiment, but there isn't much data to support it beyond the paper.

~Namaste

Here's a comment, made by the publisher, regarding the article. It further explains the information presented in the article:

The Speaker June 21, 2014 at 8:49 pm

This email from Professor Timothy Ralph, which was unfortunately received just after publication, further explains the research. Thanks again, Tim.

Dear Day,

We simulated a photon that traveled to the past and was allowed to interact with its past self. We used single photons to do this, but the time-travel was simulated by using a second photon to play the part of the past incarnation of the time travelling photon. No worm-holes are required!

The reason this is interesting is because, although general relativity appears to allow for passages to the past (i.e. closed time-like curves created for example by wormholes), the passing of macroscopic objects, like us, through them seems to lead to paradoxes. For example, I go into the past and kill myself, but then I am not alive to go into the past to kill myself…etc. However, it was first shown by David Deutsch a bit over 20 years ago that microscopic particles described by quantum mechanics (like photons) can avoid these paradoxes and you can always find a consistent description of events. Roughly speaking, this occurs because of the uncertainty principle – we can never be exactly sure of all the properties of quantum particles and this uncertainty leaves enough “wiggle room” to always find a consistent evolution.

In our paper we experimentally show that if we prepare the state of the past incarnation of the time travelling photon in just the right way then indeed we get consistent evolutions in situations where we would expect paradoxes for classically described macroscopic objects. Although the evolutions are consistent, they are unusual – breaking rules that quantum mechanics would normally obey. This is another reason it is interesting. However, I emphasize it is a simulation – we “cheat” when we prepare the 2nd photon that represents the time traveler in the past.

All the best

Tim

originally posted by: SonOfTheLawOfOne
a reply to: daaskapital

Calm down, it's not real time travel. It's only in the quantum world.

Also worth noting:

Part of the reason time travel could be freed from such paradoxes in the quantum world is that the properties of quantum particles are “fuzzy” and “uncertain,” and therefore there is “wriggle room” to avoid inconsistencies in such situations, according to Professor Ralph.

They are basically saying that because some things in quantum mechanics are still less understood than classical physics, they have room to fudge the numbers to make their theory fit against the math.

It's very compelling, and a nice thought experiment, but there isn't much data to support it beyond the paper.

~Namaste

I am calm, lol.

Yes, i understand it isn't real time travel...i just thought the experiment itself was interesting in that is provides further possibilities regarding the theories of which they were considering.

Thanks for the comment.

originally posted by: jrflipjr

Indeed hahaha

It kinda sounds more like a time loop. The moment (light) is trapped in a loop of time. The new particle travels to the loop of the past moment, interacts with it and reports back. ??

Simulation. As in, lets imagine.

Stop packing your time travel bags guys. you aint going no where, unless you close your eyes and imagine.

a reply to: Dapaga

and then it reports back and both go through and report back and then three go and report back and then four...five.... ad infinitum... and finally a photonic energy expression. Take that for what you will.

originally posted by: daaskapital
Here's a comment, made by the publisher, regarding the article. It further explains the information presented in the article:

The Speaker June 21, 2014 at 8:49 pm

This email from Professor Timothy Ralph, which was unfortunately received just after publication, further explains the research. Thanks again, Tim.

Dear Day,

We simulated a photon that traveled to the past and was allowed to interact with its past self. We used single photons to do this, but the time-travel was simulated by using a second photon to play the part of the past incarnation of the time travelling photon. No worm-holes are required!

The reason this is interesting is because, although general relativity appears to allow for passages to the past (i.e. closed time-like curves created for example by wormholes), the passing of macroscopic objects, like us, through them seems to lead to paradoxes. For example, I go into the past and kill myself, but then I am not alive to go into the past to kill myself…etc. However, it was first shown by David Deutsch a bit over 20 years ago that microscopic particles described by quantum mechanics (like photons) can avoid these paradoxes and you can always find a consistent description of events. Roughly speaking, this occurs because of the uncertainty principle – we can never be exactly sure of all the properties of quantum particles and this uncertainty leaves enough “wiggle room” to always find a consistent evolution.

In our paper we experimentally show that if we prepare the state of the past incarnation of the time travelling photon in just the right way then indeed we get consistent evolutions in situations where we would expect paradoxes for classically described macroscopic objects. Although the evolutions are consistent, they are unusual – breaking rules that quantum mechanics would normally obey. This is another reason it is interesting. However, I emphasize it is a simulation – we “cheat” when we prepare the 2nd photon that represents the time traveler in the past.

All the best

Tim

Fascinating. So they've thrown their hats in the ring for Terminator-style time travel, not a Back to the Future 2 parallel universe style paradigm.

originally posted by: Jonjonj
There is a maxim that says-once time travel is discovered it will have existed for all time-the logic of this seems irrefutable to me, the fact you can't put genies back into bottles etc...however...who knows?

There's another one that says it's only possible to travel back to the point at which the time machine was first created. If you travel before that point the time machine won't be running, therefore it can't send you back to before that point.

I first asked myself, how does a light particle or photon interact with another? Apparently it's been done.

Scientists create never-before-seen form of matter

Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, a group led by Harvard Professor of Physics Mikhail Lukin and MIT Professor of Physics Vladan Vuletic have managed to coax photons into binding together to form molecules – a state of matter that, until recently, had been purely theoretical. The work is described in a September 25 paper in Nature.

The title sounds off-topic but may help further their research. A photon being sent back in time finding its older self and creating a molecule of light. Like Siamese light twins meeting up after they're born instead of before. Just let me know when they can explain how to create a functioning wormhole between curved space.

Picture yourself going back in time and seeing an earlier version of yourself. Would you live two parallel lives at once simultaneously or would one beat the crap out of each other like antimatter canceling itself out, back into the quantum soup? Sorry, I'm in that state where I think I know, but probably have no idea!

Fascinating!!!

a reply to: daaskapital

I don't think time travel is possible.

Time isn't a ''thing'' it isn't some universal measure.

Its our perception of the earth turning.

Time doesn't exist, therefore it cannot be manipulated.

originally posted by: Agit8dChop
a reply to: daaskapital

I don't think time travel is possible.

Time isn't a ''thing'' it isn't some universal measure.

Its our perception of the earth turning.

Time doesn't exist, therefore it cannot be manipulated.

Just as travelling in 'time' is just our perception of how we travel. A mile isn't tangible either, but I just finished running 5 of them. I understand that it was just my perception of the passage of distance under my feet, but my legs hurt just the same.

originally posted by: Jonjonj
There is a maxim that says-once time travel is discovered it will have existed for all time-the logic of this seems irrefutable to me, the fact you can't put genies back into bottles etc...however...who knows?

That maxim in all probability is spot on.

originally posted by: Agit8dChop
a reply to: daaskapital

I don't think time travel is possible.

Time isn't a ''thing'' it isn't some universal measure.

Its our perception of the earth turning.

Time doesn't exist, therefore it cannot be manipulated.

You are quite wrong there mate. Time can certainly be manipulated, but monkeying with time may not be all that safe

originally posted by: Jonjonj
There is a maxim that says-once time travel is discovered it will have existed for all time-the logic of this seems irrefutable to me

Which therefore suggests that time travel will never be discovered, otherwise we would already know about it.

originally posted by: Rob48

originally posted by: Jonjonj
There is a maxim that says-once time travel is discovered it will have existed for all time-the logic of this seems irrefutable to me

Which therefore suggests that time travel will never be discovered, otherwise we would already know about it.

You wouldn't want to let people know about time travel before it exists because you could create a temporal paradox.