Simulating time travel: Doctor Who meets Professor Heisenberg

Jun 20, 2014
Doctor Who meets Professor Heisenberg
Space-time structure exhibiting closed paths in space (horizontal) and time (vertical). A quantum particle travels through a wormhole back in time and returns to the same location in space and time. Credit: Martin Ringbauer

(—University of Queensland researchers have simulated time travel using light particles. Lead author and PhD student Martin Ringbauer, from UQ's School of Mathematics and Physics, said the study used photons – single particles of light – to simulate quantum particles traveling through time and study their behavior, possibly revealing bizarre aspects of modern physics.

"The question of features at the interface between two of our most successful yet incompatible physical theories – Einstein's general relativity and ," Mr Ringbauer said.

"Einstein's theory describes the world at the very large scale of stars and galaxies, while quantum mechanics is an excellent description of the world at the very small scale of atoms and molecules."

Einstein's theory suggests the possibility of travelling backwards in time by following a space-time path that returns to the starting point in space, but at an earlier time-a closed timelike curve.

This possibility has puzzled physicists and philosophers alike since it was discovered by Kurt Gödel in 1949, as it seems to cause paradoxes in the classical world, such as the grandparents paradox, where a time traveller could prevent their grandparents from meeting, thus preventing the time traveller's birth.

This would make it impossible for the time traveller to have set out in the first place.

UQ Physics Professor Tim Ralph said it was predicted in 1991 that time travel in the quantum world could avoid such paradoxes.

"The properties of are 'fuzzy' or uncertain to start with, so this gives them enough wiggle room to avoid inconsistent time travel situations," he said.

Professor Ralph said there was no evidence that nature behaved in ways other than standard quantum mechanics predicted,but this had not been tested in regimes where extreme effects of general relativity played a role, such as near a black hole.

"Our study provides insights into where and how nature might behave differently from what our theories predict."

Examples of the intriguing possibilities in the presence of closed timelike curves include the violation of Heisenberg's uncertainty principle, cracking of quantum cryptography and perfect cloning of quantum states.

Published in Nature Communications, the paper "Experimental Simulation of Closed Timelike Curves" includes Dr Matthew Broome, Dr Casey Myers, Professor Andrew White and Professor Timothy Ralph, all from The University of Queensland.

Explore further: Research team challenges the limits of famous quantum principle

More information: Paper:… full/ncomms5145.html

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Scientists develop compact medical imaging device

6 hours ago

Scientists at the MIRA research institute, in collaboration with various companies, have developed a prototype of a handy device that combines echoscopy (ultrasound) with photoacoustics. Combining these two ...

User comments : 23

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (3) Jun 20, 2014
Your intuitive understanding of cause and effect is ass backwards. It is the future that causes the present, not the past.
(Sent from the far distant future.)
1 / 5 (4) Jun 20, 2014
Egleton, you might be hitting on the right path :) in quantum timing it all goes in reversing by relative discretion of future (unobserved) space's occupied by absolute discrete states of parallel interfering continuity of time, that is closed loops self propagate more closed loops emerging into open systems. Matrices of uncertain spaces are being compressed by strings. Many do not understand Einstein - Heisenberg axis development as a consequence of time traveling due space ever distortion paradox. What is space? 1+1 (space + time =1) but 1 is not 1 at time x +1, where x is an unobservable system!
1 / 5 (1) Jun 20, 2014
Egleton, I don't know if you're playing a serious troll or are just laying bait, but ass backwards isn't a concept unless you have a front facing forwards for contrast. These linguistic terms you espouse only exist as a virtue of the interplay between opposites or dualities.

If you take people like Heisenberg, Schrodinger, Bohm, Feynman and Dirac at face value, you would probably enter a belief system wherein everything affects everything else, every way in time. Antiparticles travelling backward in time are the same as particles moving forwards in time. Causality is then entirely misinterpreted, for cause and effect would be two sides of the same coin --> it's just that our constrained nervous systems cannot see the connective tissue between event A (perceived cause) and event B (perceived effect).

If you were to travel at relativistic speeds, time dilation would imply that you experience the totality of all events simultaneously. In other words, everything happens all at once.

3 / 5 (6) Jun 20, 2014
As a physicist and psychonaut, I see incredible parallels between relativistic travel and altered states of consciousness -- trips and voyages into inner space. In such situations of expanded awareness, one can see that everything is connected, and that there is no cause and effect. Indeed, everything is happening simultaneously, all of the time! Thus, time itself reveals itself to be the ultimate illusion, for there is no past or future. There is simply one moment - forever - stretching from here to eternity.

Whydening Gyre
not rated yet Jun 20, 2014
Well, since we are right here in the middle of now, I'd say WE create both future and past... And I have altered my state of consciousness on occasion...:-)
1 / 5 (1) Jun 20, 2014
"closed timelike curves include the violation of Heisenberg's uncertainty principle" -- I remember someone saying that not even God could know both the position and speed of a particle. All He now has to do is to observe the effects (and results) of an open timelike curve (OTC) in just one subset universe.
(He first has to exist though, to begin with, of course:-)
1 / 5 (2) Jun 20, 2014
There is a paper that uses the time travel (via time dilation) to explain quantum entanglement.

"EPR Paradox Solved by Special Theory of Relativity"
3 / 5 (2) Jun 20, 2014
People assume that time is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint - it's more like a big ball of wibbly wobbly... time-y wimey... stuff.

1 / 5 (2) Jun 20, 2014
I think the core of this article may be built on unstable foundations because it starts by suggesting Einstein(/Minkowski's) space-time suggests the possibility of time-travel.


"we quite clear as to what we understand by "time."...

If, for instance, I say, "That train arrives here at 7 o'clock," I mean something like this: "The pointing of the small hand of my watch to 7 and the arrival of the train are simultaneous events."

- But all this actually describes is the fact that objects, e.g train, or a motorised hand, can exist and move or be stationary, and that their location and or motions can be compared.

logically, the assumption that a rotating hand proves anything about the existence and passing of a thing called 'time', is, in this document -only- an assumption.

1000 chrs is to short to explain the consequences re space-time,so here's a vid

1 / 5 (2) Jun 20, 2014
ps, given the title of this article - Doctor Who meets Professor Heisenberg

And because 1000 chrs is just too short to suggest anything in detail, - anyone who saw Professor Brian Cox's "The science of Dr WHO" may also like this youtube that I produced in response to the (excellent) show, to suggest where we may have misinterpreted Relativity, and how the time-travel examples Professor Cox sites might be significantly modified.

Time Travel,Timeless Answers to Prof Brian Cox's Science of Dr WHO

not rated yet Jun 20, 2014
Time as we currently use it is no more than a progression from one moment to the next. It's a man made idea so that we can establish a routine for doing this & that. That routine might be a lot different on another planet. Moving clocks might slow in grav fields but that says nothing about the entity the clock is supposed to measure. There is nothing in that idea that would allow one to travel back to yesterday's meeting. It is also in this sense that a photon does not experience a lapse in time while the rest of us continue to age. If we try to impose this idea of our own memory on QM then we'll get no-where.
We need to re-define the 'enity' that photons etc DO experience while progressing from one position or state to the next...say a 'Time Field', which might have dimensions of its own. That is to say that the TF would allow the continued existence of each past moment, within the dimensions, so that there would be something to travel back to. cont...
5 / 5 (1) Jun 20, 2014
Well, as our 3D universe may, we posit, be a holographic projection from a 2D universe why not carry the math to its logical end? Perhaps the 2D universe is a projection of a 1D universe which, in turn, comes from a 0D universe? So, if they are ALL active then if entanglement acts at the 0D level its not only understandable, it's predictable.

As for time travel I'm sick of everyone who blabs about it n0ever defines it! This is what Einstein abhorred and why he insisted on a clear and present definition using physical instrumentality, lik clocks and meter stiks.
not rated yet Jun 20, 2014
cont. The resulting equations from such a theory might then tell us whether Time Travel in this true sense is possible or not.
But then we hit another problem. We can only travel into the future if that future already exists within such a TF, that is it is all deterministic. However, others will suggest that our future depends on the choices we make and therefore cannot exist until the choices are made. Likewise the future of the universe (including multiverse should they exist) will depend on the encounters its constituents experience under the laws that govern them.
What if waves/particles of QM are discrete manifestations of such TF dimensions?
1 / 5 (2) Jun 21, 2014
that is pure nonsense.
photons move in space only
and time is a numerical order of their motion
see our paper
not rated yet Jun 21, 2014
@AmritSorli don't confuse SR time intervals as a definition of Time or Space as a volume existing purely as a medium for our ideas.
1 / 5 (1) Jun 21, 2014
"Now" has everything in store (in superposition) for you. Our known life forms need evolution and not the experience to experience everything at once.

There's no evolution in that. Or travel.
1 / 5 (1) Jun 21, 2014
Jun 21, 2014
This comment has been removed by a moderator.
not rated yet Jun 22, 2014
There's something fundamentally odd about the idea of the grandfather paradox.

Because if you can travel through time, that implies you exist in one or few points in time and not in all points of time like a continuous line, so the past doesn't really exist when you go there. There's no grandfather to kill, because they stopped existing in that point of space-time when the past travelled into the future.

There might be something else there though.

not rated yet Jun 23, 2014
The subject is extremely important yet this article has almost no content - is meaningless.
1 / 5 (1) Jun 26, 2014
Revolutionary Quantum Entanglement Superposition System with Time Travel Aspect already developed and working: Life is Living Art website states: "My own personal subjective experiences around the idea of Quantum Entanglement shows wonderfully through many examples, that the scientists are never able to understand it all - unless they experience it subjectively themselves. After experiencing Quantum Entanglement themselves, they can bring the awareness and inner wisdom gained from the experience to the equation. Suddenly many missing links just seem to appear out of nowhere and wholeness becomes Crystal Clear: In Randomness there is Divine Order - Structure, which is contained within everything and no-thing at the same time. Here on this page I have demonstrated how the idea of Quantum Teleportation actually works and I have a solid proof of this system in action."
Jul 28, 2014
This comment has been removed by a moderator.
1 / 5 (1) Jul 28, 2014
The closed time-like curves and worm holes did become very popular in mainstream physics during last years. Why? Because they were postulated long time ago already in context of general relativity, so that many conservative theorists believe, they would allow to explain the various quantum gravity phenomena (like the paradox of black holes) without need of correction of classical theories, fundamental change the less. Unfortunately, the worm holes are still hyperdimensional phenomena, despite they're described with local 4D geometry of space-time at the above picture. and the extra-dimensions tend to violate the postulates of 4D theories automatically. In rigorous strictly 4D general relativity the closed time-like curves and time travel remain prohibited anyway.
1 / 5 (1) Jul 28, 2014
Actually, the closed worm holes at their canonical form are nearly impossible to observe in observable Universe - only the space-time tunnels between very close and dense stars could mimic their behavior. The so-called sparse worm holes are quite frequent though. They do allow only partial time travel and they're fragmented into many tiny "worm pits" due to quantum phenomena. Therefore even the sparse cloud of dark matter (scalar waves with negative energy and gravitational charge) which is forming during planetary conjunctions of solar eclipses between massive bodies can be considered as a sparse worm hole and it exhibits the time travel effects too. From this moment we are facing the problem with mainstream physicists, because these guys refuse to research just the phenomena, which they're pushing with their theories somewhere else - just because they don't actually understand their physical consequences.
1 / 5 (1) Jul 28, 2014
The worm holes are otherwise extremely important with respect to their ability to violate the entropic time arrow and causality given with conservation of energy and Gauss theorem of Coulomb and gravitational law in form of magnetic motors and monopoles, antigravity beams and another phenomena, which are generally considered as a subject of "crackpot science" today- despite they're all dealing just with "extradimensional" and "quantum gravity" phenomena, which the contemporary theorists struggle to detect.

The memo is, the fact you're understanding the math and you've even developed some theory for physical phenomena still doesn't mean, you're already understanding all its observable consequences.