Scientists have built world’s first ‘time machine’ in experiment

a reply to: neoholographic

I'm not talking about a warp drive that bends space at a singular point in space. I'm talking about returning to the initial state which would require lowering the entropy of the universe.

Wouldn't this be a requirement before engaging in warp travel? At least locally? If I understand this correctly, in order for you to "travel" by bending space you have to lower entropy in the universe? Isn't this simulation an example of a system that is a proof of principle?




An Alcubierre drive IS technically a time machine and it can violate causality. Currently, warp drive is not known to be harmonious with the 2nd Law of Thermodynamics specifically because of how it can violate 'c'. I'm wondering if the equations in this simulation that reversed the entropy of a wave packet can be applied to the compression of space in a warpfield tensor equation.

You're just creating some kind of wormhole or bridge.

Alcubierre's hypothesis does not make use of Einstein-Rosen bridges or any other form of wormhole dynamics.

I'm not talking about a warp drive that bends space at a singular point in space. I'm talking about returning to the initial state which would require lowering the entropy of the universe.

You have to factor this in any time you have a system that violates causality.

originally posted by: dubiousatworst
sorry to rain on people's parade
www.technologyreview.com...

As Scott Aaronson, director of the Quantum Information Center at the University of Texas at Austin, says, “If you’re simulating a time-reversible process on your computer, then you can ‘reverse the direction of time’ by simply reversing the direction of your simulation. From a quick look at the paper, I confess that I didn’t understand how this becomes more profound if the simulation is being done on IBM’s quantum computer.”

Again, the paper you quoted seems to be arguing against time travel which makes no sense. It's not talking about sending a human back in time, it's about entropy.

a reply to: projectvxn

You said:

Wouldn't this be a requirement before engaging in warp travel? At least locally? If I understand this correctly, in order for you to "travel" by bending space you have to lower entropy in the universe? Isn't this simulation an example of a system that is a proof of principle?

We can lower the entropy of the universe locally. When you clean your room or paint your house you're lowering entropy locally but the overall entropy of the universe increases. So you we can never move in a direction towards lower entropy which would be a more ordered state.

Warp drive doesn't need to lower the entropy of the universe.

What this specifically showed was that the initial low entropy state was accessible to the system.

So as the system grows, the initial state isn't accessible to observers in an isolated system. This doesn't mean it doesn't exist, we just can't move in a direction towards lower entropy. Here's more from the paper.

A time-reversal operation Rˆ of the qubit register can be presented as a product Rˆ = UˆRKˆ of the complex conjugation operator Kˆ , Kˆ (ψi |ii) ≡ ψ ∗ i |ii, and some unitary operator UˆR, whose form is defined by the Hamiltonian Hˆ , UˆR = Uˆ † HUˆ ∗ H, where Hˆ = Uˆ † Hdiag[E1 . . . En]UˆH, see Appendix B. Therefore, in order to implement the time-reversal operation Rˆ one needs to know the Hamiltonian Hˆ explicitly. Note, that quantum computer is able to simulate unitary dynamics governed by an arbitrary Hamiltonian including those that do not correspond any physical system (for example, some non-local Hamiltonian). It is known, that the joint transformation of the charge conjugation, parity inversion, and time reversal is considered as an exact symmetry of all known laws of physics, and, therefore, the qubit Hamiltonian Hˆ , which corresponds to a real physical system, has to honor this symmetry as well. Therefore, the unitary operation describing evolution of the physical system UˆR is generally known and represents a transformation which is inherited from the time-reversal symmetry of the original Hamiltonian Hˆ. In particular, if the qubit Hamiltonian Hˆ is real, then the corresponding evolution operator Uˆ(τ ) = e −iHτ/ ˆ ~ is symmetric that entails UˆR = 1.

This is pretty technical but the Hamilton of the Qubit corresponds to a physical system but the quantum computer can be governed by any arbitrary Hamilton even those that DO NOT CORRESPOND to a physical system.

So as the system goes from order to chaos the original Hamilton shouldn't be accessible to it.

It's about a system returning to it's initial state(H) spontaneously which should be impossible but it happened with an 85% success rate with a 2 Qubit quantum computer and it dropped to 50% with a 3 Qubit quantum computer. They concluded with this:

Our findings break ground for investigations of the time reversal and the backward time flow in real quantum systems. One of the challenging directions to pursue, is the time dependence of the reversal complexity N of an evolving quantum state. In our work, we have shown that an isolated d-dimensional quantum particle with quadratic spectrum exhibits a polynomial complexity growth N (τ ) = τ d . Uncovering the N (τ ) dependence for realistic situations, accounting for the interactions will establish a mechanism and the corresponding timescale on which time-reversed states can spontaneously emerge. Another fundamental question is whether it is possible at all to design a quantum algorithm that would perform time-reversal more efficiently than using O(N ) elementary gates? So far, our time-reversal schemes were scrolling one by one through the state components but did not exploit a quantum parallelism in its full power.

arxiv.org...

So as a system grows, the information to describe the initial state becomes less accessible. So entropy can be seen as hidden information.

So this is time travel or a more technical way to describe it would be travel in the direction of lower entropy toward the initial state.

a reply to: neoholographic

I do understand the experiment.

This is what I also said:

I'm wondering if the equations in this simulation that reversed the entropy of a wave packet can be applied to the compression of space in a warp field tensor equation.

It most certainly does have to deal with entropy.

Causality violation and semiclassical instability

Causality violation and semiclassical instability
Calculations by physicist Allen Everett show that warp bubbles could be used to create closed timelike curves in general relativity, meaning that the theory predicts that they could be used for backwards time travel.[28] While it is possible that the fundamental laws of physics might allow closed timelike curves, the chronology protection conjecture hypothesizes that in all cases where the classical theory of general relativity allows them, quantum effects would intervene to eliminate the possibility, making these spacetimes impossible to realize (a possible type of effect that would accomplish this is a buildup of vacuum fluctuations on the border of the region of spacetime where time travel would first become possible, causing the energy density to become high enough to destroy the system that would otherwise become a time machine). Some results in semiclassical gravity appear to support the conjecture, including a calculation dealing specifically with quantum effects in warp-drive spacetimes that suggested that warp bubbles would be semiclassically unstable,[10][29] but ultimately the conjecture can only be decided by a full theory of quantum gravity.[30]

Miguel Alcubierre briefly discusses some of these issues in a series of lecture slides posted online,[31] where he writes: "beware: in relativity, any method to travel faster than light can in principle be used to travel back in time (a time machine)". In the next slide he brings up the chronology protection conjecture and writes: "The conjecture has not been proven (it wouldn’t be a conjecture if it had), but there are good arguments in its favor based on quantum field theory. The conjecture does not prohibit faster-than-light travel. It just states that if a method to travel faster than light exists, and one tries to use it to build a time machine, something will go wrong: the energy accumulated will explode, or it will create a black hole."

This is what I'm getting at. If you can do this with a quantum system, you are essentially saying that the chronology protection conjecture is wrong and that causality, at least in a quantum system with regard to the 2nd law, can be readily violated, at least in THIS case, could those equations not be applied to Alcubierre's tensor metric? If not, why not?

a reply to: neoholographic

It works because our universe is binary

a reply to: purplemer

If that were the case you'd be able to break down every system using boolean algebra and truth tables.

It's not quite that simple.

originally posted by: purplemer
a reply to: neoholographic

It works because our universe is binary

EXACTLY

originally posted by: projectvxn
a reply to: purplemer

If that were the case you'd be able to break down every system using boolean algebra and truth tables.

It's not quite that simple.

Tis to me. I meant we live in a binary universe. Our universe is paired.

a reply to: purplemer

The fact that we aren't all low energy photons right now means that this is not the case.

a reply to: projectvxn

You said:

This is what I'm getting at. If you can do this with a quantum system, you are essentially saying that the chronology protection conjecture is wrong and that causality, at least in a quantum system with regard to the 2nd law, can be readily violated, at least in THIS case, could those equations not be applied to Alcubierre's tensor metric? If not, why not?

Yes, the 2nd law is violated in this case. This has nothing to do with warping space, this is a matter of information. Here's more:

Quantum Maxwell's demon 'teleports' entropy out of a qubit

Researchers from the Moscow Institute of Physics and Technology, ETH Zurich, and Argonne National Laboratory, U.S, have described an extended quantum Maxwell's demon, a device locally violating the second law of thermodynamics in a system located 1-5 meters away from the demon. The device could find applications in quantum computers and microscopic refrigerators cooling down tiny objects with pinpoint accuracy. The research was published Dec. 4 in Physical Review B.

The second law says that the entropy -- that is, the degree of disorder or randomness -- of an isolated system never decreases.

"Our demon causes a device called a qubit to transition into a more orderly state," explained the study's lead author Andrey Lebedev of MIPT and ETH Zurich. "Importantly, the demon does not alter the qubit's energy and acts over a distance that is huge for quantum mechanics."

www.eurekalert.org...

Again, this is a matter of information. The Qubit's energy isn't altered so it's about information.

As a system grows, the information to describe the system changes. Here's M.I.T. Professor Seth Lloyd talking about this.

Time’s Arrow Traced to Quantum Source

Using an obscure approach to quantum mechanics that treated units of information as its basic building blocks, Lloyd spent several years studying the evolution of particles in terms of shuffling 1s and 0s. He found that as the particles became increasingly entangled with one another, the information that originally described them (a “1” for clockwise spin and a “0” for counterclockwise, for example) would shift to describe the system of entangled particles as a whole. It was as though the particles gradually lost their individual autonomy and became pawns of the collective state. Eventually, the correlations contained all the information, and the individual particles contained none. At that point, Lloyd discovered, particles arrived at a state of equilibrium, and their states stopped changing, like coffee that has cooled to room temperature.

“What’s really going on is things are becoming more correlated with each other,” Lloyd recalls realizing. “The arrow of time is an arrow of increasing correlations.”

www.quantamagazine.org...

I don't know if you're familiar with the recent move towards space-time as an error correcting code and the connection between entanglement, entropy and information.

So what you will have here is a quantum computer that can go back in time. Imagine what that could mean. It would be able to go back in time and correct itself. Here's the Author of the study talking about this:

Researchers reverse the flow of time on IBM's quantum computer

Researchers have managed to return a computer briefly to the past. The results suggest new paths for exploring the backward flow of time in quantum systems. They also open new possibilities for quantum computer program testing and error correction.

An international team of scientists led by the U.S. Department of Energy's (DOE) Argonne National Laboratory explored this question in a first-of-its-kind experiment, managing to return a computer briefly to the past. The results, published March13 in the journal Scientific Reports, suggest new paths for exploring the backward flow of time in quantum systems. They also open new possibilities for quantum computer program testing and error correction.

To achieve the time reversal, the research team developed an algorithm for IBM's public quantum computer that simulates the scattering of a particle. In classical physics, this might appear as a billiard ball struck by a cue, traveling in a line. But in the quantum world, one scattered particle takes on a fractured quality, spreading in multiple directions. To reverse its quantum evolution is like reversing the rings created when a stone is thrown into a pond.

In nature, restoring this particle back to its original state -- in essence, putting the broken teacup back together -- is impossible.

The result deepens our understanding of how the second law of thermodynamics -- that a system will always move from order to entropy and not the other way around -- acts in the quantum world. The researchers demonstrated in previous work that, by teleporting information, a local violation of the second law was possible in a quantum system separated into remote parts that could balance each other out.

The finding may eventually enable better methods of error correction on quantum computers, where accumulated glitches generate heat and beget new ones. A quantum computer able to effectively jump back and clean up errors as it works could operate far more efficiently.

The study also raises the question: can the researchers now figure out a way to make older folks young again? ​"Maybe," Vinokur jokes,​ "with the proper funding."

www.sciencedaily.com...

Clearly, this is time travel or you can say time reversal. If I drop my favorite glass and it breaks then I reverse time to the point before I broke the glass then I have time traveled. Like I said though this might be impossible for larger systems but you don't know what we might know 50-100 years from now.

At the end of the day it might not even be a violation because the 2nd law as we know it might emerge from entanglement.

So what exactly don't you understand?

a reply to: neoholographic

I addressed coherence and by extension error correcting in quantum computers as a consequence of this research already.

It was on page one. Maybe you missed it.

I'm not saying it has anything to do with creating warp bubbles. But a means of correcting for violations of causality in Alcubierre's metric and running that simulation to see what happens.

So what exactly don't you understand?

Nothing. You're refusing to understand what it is I'm trying to say.

I'm asking if, as a matter of practicality, can a time machine similar to Alcubierre's warp drive that violates causality (backward time travel) benefit from understanding how time-reversal in a quantum system is achieved and whether this could help map a way to achieve this theoretically before attempting to produce a real high energy warp field for experimental use.

I'm asking if this type of experimental data can be shown to illuminate a condition in the universe where time travel to the past (reversing entropy) shows the chronology preservation conjecture to be incorrect.

a reply to: neoholographic

So time travel was achieved on a very limited basis. In order to travel back in time, you would have to reverse entropy of the system back towards the initial state. I don't think that's possible for classical systems but it happened here.

This may have more to do with quantum entropy limited by for lack of a better word "granularity".
You can't walk a Planck length because the shortest stride you could take is the length of the planck.

a reply to: neoholographic

I think it might be worthwhile to review what a Hamiltonian is - this video from D-Wave gives a nice description as it relates to quantum computing.

I'm not sure about the "time reversal" element in the paper. It sounds more like returning to an original state of the elections. And I guess that implies a lower entropy state. But wouldn't everything associated with the electrons, including the quantum computer itself, necessarily have to return to their original state when the experiment was initiated? I don't know. Just one of many questions I have about the paper.

Anyway, here's the video:

originally posted by: projectvxn
a reply to: purplemer

The fact that we aren't all low energy photons right now means that this is not the case.

Can you explain that a bit more for me plz.

a reply to: purplemer

Care to explain what you mean by binary?

Boolean logic doesn't explain the universe or how it functions.

originally posted by: projectvxn
a reply to: purplemer

Care to explain what you mean by binary?

Boolean logic doesn't explain the universe or how it functions. [/quote

Hermetic Principles. Everything has an opposite or opposing pole. Our universe being no different. That is all I mean by binary.

a reply to: projectvxn

When looking at the world at a quantum state is becomes clear that consciousness may well be a force. It has an action on the material world. This being so it may well be a possibility that that matter is created out of conciseness. If this is the case how would it fit in with you theories of time travel.


Again this fits in well with hermatic principles. The first of which states something like The law of mind states that everything is mental in nature:

a reply to: purplemer

Ok. I'm talking science here, not made up mysticism that has nothing to do with binary or anything else you're going on about.

a reply to: projectvxn

Unless you understand what I am talking about then you above point is mute. The hermetics philosophy is a science and my question to you was based on the principles of science.


So why are you bringing yourself across as obtuse. It was just a question and you could have tried to answer ot

a reply to: purplemer

Unless you understand what I am talking about then you above point is mute.

The word is moot.

We're discussing quantum systems and you brought up binary.

Now you're bringing BS mysticism into it like it's valid.

Try again.