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Scientists simulate backward time travel using quantum entanglement

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Re: Scientists simulate backward time travel using quantum entanglement

#41

Post by trulyunruly »

forgotusername6 wrote: post #38
chrisweekly wrote: post #17

Earlier quoted context omitted.

"Our Gedankenexperiment demonstrates that..." "Gedankenexperiment" sounds an awful lot like "thought experiment".

This has just unlocked a childhood memory of mine. I read a book as a young child about a girl and her grandfather who did experiments about space and time. The girl's name was Gedanken. It explored some of Einstein's theories in the form of short adventures. I've been struggling to find the name of the book. Does anyone else remember this book?

”The book you're remembering is likely "Mr. Tompkins" by George Gamow. The series features the character Mr. Tompkins, but in "Mr. Tompkins in Paperback" (which combines "Mr. Tompkins in Wonderland" and "Mr. Tompkins Explores the Atom"), he has a daughter named Gedanken. The stories are known for their accessible exploration of advanced scientific concepts, including those related to Einstein's theories, through fantastical adventures.” - GPT-4

Re: Scientists simulate backward time travel using quantum entanglement

#42

Post by [deleted] »

forgotusername6 wrote: post #38
chrisweekly wrote: post #17

Earlier quoted context omitted.

"Our Gedankenexperiment demonstrates that..." "Gedankenexperiment" sounds an awful lot like "thought experiment".

This has just unlocked a childhood memory of mine. I read a book as a young child about a girl and her grandfather who did experiments about space and time. The girl's name was Gedanken. It explored some of Einstein's theories in the form of short adventures. I've been struggling to find the name of the book. Does anyone else remember this book?

[deleted]

Re: Scientists simulate backward time travel using quantum entanglement

#43

Post by mjan22640 »

tobiasSoftware wrote: post #24
halfcat wrote: post #19

Earlier quoted context omitted.

> unlikely to make a meaningful difference at distances measured less than how far light travels in that time PBS Space Time did an episode that posed the question as a delayed choice quantum eraser experiment where the “long” leg is farther away, like on the moon, and we somehow reflect a particle back and forth to delay the observation indefinitely. I also wonder if they can do something like this at CERN. Their co…

The delayed choice quantum eraser is misunderstood (even by PBS Spacetime) to invoke time travel/retrocausality. The truth is that the pattern seen on the screen is the same whichever set of detectors you send it to, and as such, there is no evidence of time travel. The more plausible explanation behind the delayed choice quantum eraser involves Heisenberg's Uncertainty Principle, which states that you cannot obtain…

Have a look at time double slit, a spot in a material being made transparent twice in a quick succession. A photon travels through both and interferes, ie the future interfes with the past, and the Feynman path integral encompasses also paths through time.

Re: Scientists simulate backward time travel using quantum entanglement

#44

Post by omnicognate »

trulyunruly wrote: post #41
forgotusername6 wrote: post #38

Earlier quoted context omitted.

This has just unlocked a childhood memory of mine. I read a book as a young child about a girl and her grandfather who did experiments about space and time. The girl's name was Gedanken. It explored some of Einstein's theories in the form of short adventures. I've been struggling to find the name of the book. Does anyone else remember this book?

”The book you're remembering is likely "Mr. Tompkins" by George Gamow. The series features the character Mr. Tompkins, but in "Mr. Tompkins in Paperback" (which combines "Mr. Tompkins in Wonderland" and "Mr. Tompkins Explores the Atom"), he has a daughter named Gedanken. The stories are known for their accessible exploration of advanced scientific concepts, including those related to Einstein's theories, through fant…

AFAICT there is no character named "Gedanken" in that book. The correct book was findable in a few seconds with a traditional search engine: The Time and Space of Uncle Albert by Russell Stannard [1].

[1] https://books.google.co.uk/books/about/The_Time_and_Space_of...

Re: Scientists simulate backward time travel using quantum entanglement

#45

Post by Yoric »

mdekkers wrote: post #25
chrisweekly wrote: post #17

Earlier quoted context omitted.

"Our Gedankenexperiment demonstrates that..." "Gedankenexperiment" sounds an awful lot like "thought experiment".

That’s literally what it means, and it’s a minor nitpick I have - it’s an English paper, just use English. Using the German word here just increases noise.

It's a pretty common word in research. After all, "thought experiment" is actually a translation from German.

Re: Scientists simulate backward time travel using quantum entanglement

#46

Post by corney91 »

dr_kiszonka wrote: post #32
galaxyLogic wrote: post #29

Earlier quoted context omitted.

I think it comes from Einstein whose Gedanken Experiments lead to the discovery of relativity. Einstein came from a German-speaking country. So what the authors are saying is "We're basically doing a similar thing as Einstein did". Jargon is to be avoided but this is more like a tribute to the great physicist Einstein.

A less charitable interpretation would be that is a form of self-aggrandizement.

It's a pretty standard word used in quantum physics.

Source: I did a masters in the subject and remember reading it a lot.

Re: Scientists simulate backward time travel using quantum entanglement

#47

Post by trulyunruly »

omnicognate wrote: post #44
trulyunruly wrote: post #41

Earlier quoted context omitted.

”The book you're remembering is likely "Mr. Tompkins" by George Gamow. The series features the character Mr. Tompkins, but in "Mr. Tompkins in Paperback" (which combines "Mr. Tompkins in Wonderland" and "Mr. Tompkins Explores the Atom"), he has a daughter named Gedanken. The stories are known for their accessible exploration of advanced scientific concepts, including those related to Einstein's theories, through fant…

AFAICT there is no character named "Gedanken" in that book. The correct book was findable in a few seconds with a traditional search engine: The Time and Space of Uncle Albert by Russell Stannard [1]. [1] https://books.google.co.uk/books/about/The_Time_and_Space_of...

Cunningham's Law:) I was only hoping to provide some direction. But thank you for finding the right answer.

Re: Scientists simulate backward time travel using quantum entanglement

#48

Post by gerad »

DaveSchmindel wrote: post #15
pama wrote: post #8

Earlier quoted context omitted.

There is a nice explanation at the end of the letter: “While PCTC simulations do not allow you to go back and alter your past, they do allow you to create a better tomorrow by fixing yesterday’s problems today.”

Interesting. Isn't that just problem solving? If yesterday's problems are unsolved by today, aren't they just today's problems?

I read it as:

- Today, I need to predict tomorrow’s weather.

- Yesterday I made some measurements of the (temperature, pressure, etc) conditions that I need for today’s prediction.

- Yesterday it was impossible to know what measurements I’d optimally need to take for today’s forecast.

- Today, I can (quantumly, probabilisticly) go back in time and make sure I have the optimal set of measurements for today’s prediction.

- I can’t change anything that happened between yesterday and today, but I now have better information I can use to change tomorrow.

Re: Scientists simulate backward time travel using quantum entanglement

#49

Post by omnicognate »

trulyunruly wrote: post #47
omnicognate wrote: post #44

Earlier quoted context omitted.

AFAICT there is no character named "Gedanken" in that book. The correct book was findable in a few seconds with a traditional search engine: The Time and Space of Uncle Albert by Russell Stannard [1]. [1] https://books.google.co.uk/books/about/The_Time_and_Space_of...

Cunningham's Law:) I was only hoping to provide some direction. But thank you for finding the right answer.

I found and posted the answer in parallel with you, and then deleted my direct response when I replied to yours (at greater length as I initially posted only the link, which was sufficient for merely answering the question).

I don't think the posting of unverified ChatGPT snippets in response to factual questions on HN has value.

Re: Scientists simulate backward time travel using quantum entanglement

#50

Post by MrRolleyes »

andreareina wrote: post #2

Paper: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.13... > We construct a metrology experiment in which the metrologist can sometimes amend the input state by simulating a closed timelike curve, a worldline that travels backward in time. The existence of closed timelike curves is hypothetical. Nevertheless, they can be simulated probabilistically by quantum-teleportation circuits. We leverage such simul…

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