Alan Burdock. Why Time Flies: A mostly scientific investigation. 2017. physics, psychology, et cetera of time.
Craig Callender. What makes time special? 2017. Unusually deep examination of what we mean by time.
Allen Everett and Thomas Roman. Time travel and warp drives: A scientific guide to shortcuts through time and space. 2012. Title says it all.
Matthew Jones and Joan Ormrod. Time Travel in Popular Media: Essays on Film, Television, Literature, and Video Games. 2015. Interesting collection of essays. Has a section on Asian Time Travel Films & Television Series.
Paul J. Nahin. Time Travel Tales: The Science Fiction Adventures and Philosophical Puzzles of Time Travel. 2017. Usual first rate work by Nahin.
Fraser A. Sherman. Now and Then We Time Travel. 2017. Very good coverage of film & television. Recommends Aetherco, Epguides, and Wikipedia. All good sources as well.
Ryan Wasserman. Paradoxes of Time Travel. 2018. Good review of various paradoxes from a philosophical point of view.
David Wittenberg. Time travel: the popular philosophy of narrative. 2013. My favorite as an explanation of what the function of time travel is, from a narrative point of view. Why do authors use time travel?
]]>The central question in the paper is “is time fuzzy? or is it flat?” Or in more technical language, “it time an observable? or is it a mere parameter?”
To recap, in relativity, time and space enter on a basis of formal equivalence. In special relativity, the time and space coordinates rotate into each other under Lorentz transformations. In general relativity, if you fall into a black hole time and the radial coordinate appear to change places on the way in. And in wormholes and other exotic solutions to general relativity, time can even curve back on itself.
For all its temporal shenanigans, in relativity everything has a definite position in time and in space. But in quantum mechanics, the three space dimensions are fuzzy. You can never tell where you are exactly along the x or y or z positions. And as you try to narrow the uncertainty in say the x dimension, you inevitably (“Heisenberg uncertainty principle”) find the corresponding momentum increasing in direct proportion. The more finely you confine the fly, the fiercer it buzzes to escape. But if it were not for this effect, the atoms that make us — and therefore we ourselves in turn — could not exist (more in the paper on this).
So in quantum mechanics space is complex, but time is boring. It is well-defined, crisp, moves forward at the traditional second per second rate. It is like the butler Jeeves at a party at Bertie Wooster’s Drone’s Club: imperturbable, stately, observing all, participating in nothing.
Given that quantum mechanics and relativity are the two best theories of physics we have, this curious difference about time is at a minimum, how would Jeeves put it to Bertie?, “most disconcerting sir”.
Till recently this has been a mere cocktail party problem: you may argue on one side, you may argue on the other, but it is more an issue for the philosophers in the philosophy department than for the experimenters in the physics department.
But about two years ago, a team led by Ossiander managed to make some experimental measurements of times less than a single attosecond. As one attosecond is to a second as a second is to the age of the universe, this is a number small beyond small.
But more critically for this discussion, this is roughly about how fuzzy time would be if time were fuzzy. A reasonable first estimate of the width of an atom in time is the time it would take light to cross the atom — about an attosecond.
And this means that we can — for the first time — put to experimental test the question: is time fuzzy or flat? is time an observable or a parameter?
To give the experimenters well-defined predictions is a non-trivial problem. But it’s doable. If we have a circle we can make some shrewd estimates about the height of the corresponding sphere. If we have an atomic wave function with well-defined extensions in the three space dimensions, we can make some very reasonable estimates about its extent in time as well.
The two chief effects are non-locality in time as an essential aspect of every wave function and the complete equivalence of the Heisenberg uncertainty principle for time/energy to the Heisenberg uncertainty principle for space/momentum.
In particular, if we send a particle through a very very fast camera shutter, the uncertainty in time is given by the time the camera shutter is open.
In standard quantum mechanics, the particle will be clipped in time. Time-of-arrival measurements at a detector will show correspondingly less dispersion.
But if time is fuzzy, then the uncertainty principle kicks in. The wave function will be diffracted by the camera shutter. If the uncertainty in time is small, the uncertainty in energy will be large, the particle will spread out in time, and time-of-arrival measurements will show much greater dispersion.
Time a parameter — beam narrower in time. Time an observable — beam much wider in time.
And if we are careful we can get estimates of the size of the effect in a way which is not just testable but falsifiable. If the experiments do not show the predicted effects at the predicted scale, then time is flat.
Of course, all this takes a bit of working out. Hence the long paper.
There was a lot to cover: how to do calculations in time on the same basis as in space, how to define the rules for detection, how to extend the work from single particles to field theory, and so on.
The requirements were:
I’ve been helped by many people along the way, especially at the Feynman Festivals in Baltimore & Olomouc/2009; at some conferences hosted by QUIST and DARPA; at The Clock and the Quantum/2008 conference at the Perimeter Institute; at the Quantum Time/2014 conference Pittsburgh; at Time and Quantum Gravity/2015 in San Diego; and most recently at the Institute for Relativistic Dynamics (IARD) conference this year in Yucatan. An earlier version of this paper was presented as a talk at this last conference & feedback from the participants was critical in helping to bring the ideas to final form.
Many thanks!
The paper has been submitted to the IOP Conference Proceedings series. The copy on the archive is formatted per the IOP requirements so is formatted for A4 paper, and with no running heads or feet. I have it formatted for US Letter here.
Why do we want to go? How do we get there? How do we live there? What might we find? What are the dangers: radiation, low gravity, dust, our fellow humans? Is there life on Mars now? Was there once? and did our own evolution actually start on Mars?
And I’m doing six panels besides: Mars, Mars, Mad Scientists, Black Holes, Star Trek versus Star Wars, and Evil Tech. Seems to be aimed generally in a pretty sinister direction! War planets, mad scientists, all-devouring black holes, death stars versus battle-cruisers, and generally evil tech. Curious. I hope Philcon programming knows that I’m largely opposed to evil.
John Ashmead (mod)
What they are, what they are NOT, why it’s A Bad Idea to confuse a black hole with a wormhole, and how to use them in scientifically accurate ways in your writing.
Dr. Valerie J. Mikles (mod), Bob Hranek, John Ashmead, Jay Wile, Peter Prellwitz
How do these universes differ in the ways they depict their tech? How did the history of each world affect the invention and uses of medical devices, weaponry, methods of transportation, and robotic beings?
Jeff Warner (mod), John Ashmead, Inge Heyer, Jay Wile, Anna Kashina, Glenn Hauman
How do we expect to change the galactic landscape in an ethical way, and what can we do as humans to decrease our impact on it? What does it mean to establish human settlements on worlds not our own? A discussion of space travel, space colonies, and morality.
Jazz Hiestand (mod), John Ashmead, Inge Heyer, Tom Purdom, Tobias Cabral, Joseph Haughey
Why do we want to go? How do we get there? How do we live there? What might we find? What are the dangers: radiation, low gravity, dust, our fellow humans? Is there life on Mars now? Was there once? and did our own evolution actually start on Mars?
John Ashmead (mod)
Since the days of H.G. Wells, Mars has figured greatly in SF. How have SF views of Mars changed as our understanding of the planet grew. Why does it still matter today?
Jazz Hiestand (mod), John Ashmead, Michael D’Ambrosio, Paul Levinson, Tobias Cabral
What’s the hottest tech about to change our world? Join us to discuss the promise, threat, and some things people usually don’t want to talk about.
Bob Hranek (mod), John Ashmead, Earl Bennett, Charlie Robertson, John Skylar
Despite a long history in fiction of solo geniuses making the ultimate breakthroughs in their basement labs, collaboration is necessary for scientific advancement. So why do we glorify the loner scientist trope? Can we make collaborative science feel equally heroic? How do we portray science being done realistically while still meeting the needs of the story?
Jim Stratton (mod), John Ashmead, Aaron Feldman, Anna Kashina, Alan P. Smale, Tee Morris
]]>I’m doing my Practical Telepathy talk at Capclave tomorrow 9/29/2018 (Saturday) at 12:00 pm:
Practical Telepathy: the Science and Engineering of Mind-to-Mind communication. (Ends at: 12:55 pm) Washington Theater
From van Vogt’s Slan to Willis’s Crosstalk, telepathy has been a staple of science fiction. But what are the real world chances of reading another person’s mind? With MRI & PET scans we can see what images a person is thinking of, with brain implants we can help the blind to see, and — the way the science is going — we are only a half-step away from direct mind-to-mind communication. Nothing to worry about here!
I have the latest version up on Slideshare.
Then I am doing two panels:
Saturday 7:00 pm: Even Hard SF uses FTL
What science is taken for granted in SF and can it really happen? What new scientific discoveries are more likely than others? What science is underused in SF?
I’m on with Catherine Asaro and David Bartell for that.
Sunday 11:00 am: What Do We Do With Sentient AI
Can your toaster have the right to vote? (Only if it is a Brave Little Toaster!)
I’m moderating with moderatees: Mark Laporta, Edward M. Lerner, James Morrow
]]>I will be speaking on Practical Telepathy at the 2018 World Science Fiction Convention in San Jose.
I just finished the final run thru on this & am very much looking forward to this. I plan to have a lot of fun with my audience; with any luck will leave many of them touching their heads nervously on the way out, wondering if the old gray matter is quite screwed on correctly.
I’m at 2pm Friday August 17th, 2018, in case any of you are going to the WorldCon in San Jose. But if not you see can the talk as PDF, Power Point, or Keynote.
Questions, comments, suggestions, may be added to the comments — or simply sent as telepathic suggestions!
]]>I will be speaking at the 2018 meeting of the IARD — The International Association for Relativistic Dynamics this afternoon. Had a nice chat with the organizers & some early arrivals last night over coffee: my talk clearly a good fit to the conference.
The decisive test is what happens if you send a quantum wave function through a single slit in time, say a very fast camera shutter. If quantum mechanics does not apply (current generally accepted view), the wave function will be clipped — and the dispersion at a detector arbitrarily small. If quantum mechanics does apply (proposal here), the wave function will be diffracted — and the dispersion at a detector arbitrarily great.
I’ve uploaded the talk itself in several formats Time Dispersion in Quantum Mechanics – Keynote, Time Dispersion in Quantum Mechanics – Powerpoint, and Time Dispersion in Quantum Mechanics – PDF.
I’ve incorporated feedback from the IARD conference into the underlying paper Time Dispersion in Quantum Mechanics. I’ve submitted this to the IOP Conference Proceedings series & have also uploaded it to the physics archive. I hope it will be a useful contribution to the literature on time and quantum mechanics.
Your comments very welcome!
]]>]]>In quantum mechanics the time dimension is treated as a parameter, while the three space dimensions are treated as observables. This assumption is both untested and inconsistent with relativity.
From dimensional analysis, we expect quantum effects along the time axis to be of order an attosecond. Such effects are not ruled out by current experiments. But they are large enough to be detected with current technology, if sufficiently specific predictions can be made.
To supply such we use path integrals. The only change required is to generalize the usual three dimensional paths to four. We treat the single particle case first, then extend to quantum electrodynamics.
We predict a large variety of testable effects. The principal effects are additional dispersion in time and full equivalence of the time/energy uncertainty principle to the space/momentum one. Additional effects include interference, diffraction, resonance in time, and so on.
Further the usual problems with ultraviolet divergences in QED disappear. We can recover them by letting the dispersion in time go to zero. As it does, the uncertainty in energy becomes infinite — and this in turn makes the loop integrals diverge. It appears it is precisely the assumption that quantum mechanics does not apply along the time dimension that creates the ultraviolet divergences.
The approach here has no free parameters; it is therefore falsifiable. As it treats time and space with complete symmetry and does not suffer from the ultraviolet divergences, it may provide a useful starting point for attacks on quantum gravity.
The talk has been rescheduled: it is now April 4th, 2018, same place: University of the Sciences, same time: 7pm.
Some new stuff: thanks to the 7th observation of a gravitational wave, the speed of gravitational waves is now known to be the speed of light. And researchers have built a carillion using black hole frequencies as the pipes.
I’ll be doing my StarGates talk at the Philadelphia Linux meeting at the University of the Sciences this coming Wednesday.
Why StarGates & Linux?
As to #1, if you are reading this the odds are you are already current with the cool of each.
And #2 goes without saying: Linux is an amazing work, putting the most powerful general purpose operating system in the hands of the open source community, in the hands of the world.
But #3 — extending the limits of the possible — is what I will be focusing on in my presentation: by asking questions about the impossible, we can extend the reach of the possible: get our grasp a bit closer to our reach, as the saying goes.
So March 7th, at the University of the Sciences in Philadelphia, at 8pm, great if you can make it, and if not, have your imagination hop over & have a look.
To infinity and beyond!
]]>I’ve just posted the slides from my Philcon 2017 talk Practical Telepathy: the Science & Engineering of Mind-Reading:
]]>Talk went well: SRO & the audience & I definitely on the same wavelength! As it were…
So slides now up, some great references on the last slide, & any questions/comments please let me know!
Thanks!
John
I’ll be speaking at 4pm Saturday November 11th, this coming Saturday, in Crystal Ballroom Two at Philcon. Hope to see you there!
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