Time Dispersion in Quantum Mechanics

If a quantum wave function goes through a single slit in time is it diffracted or clipped?

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!

Time and Quantum Mechanics accepted at IARD conference

The physics paper I’ve been working on for several years, Time & Quantum Mechanics, has been accepted for presentation at a plenary session of the 2018 meeting of  the IARD — The International Association for Relativistic Dynamics. I’m very much looking forward to this:  the paper should be a good fit to the IARD’s program.

Abstract:

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.

A Star Gate to Washington DC opens tomorrow

A fourth gravitational wave has been detected. Three solar masses worth of gravitational energy released, leaving a 53 solar mass black hole behind.

As I do my now more than highly polished presentation on StarGates:  the Theory & Practice.

New developments, just in the last week:

1. A fourth gravitational wave was detected last week, 9/27/2017.  This was far more finely localized than the previous; 25 observatories are looking for signs of the event in the electromagnetic spectrum.
2. And Kip Thorne — inventor of scientifically plausible StarGates — was awarded the Nobel Prize this week for his work on developing feasible gravitational wave detectors.   Perhaps someday he will be even more famous as the inventor of StarGates!

So I’ve folded these in my talk & look forward to giving it tomorrow at 3pm at Capclave, the Washington DC Science Fiction Convention. If you are in the area, I hope to see you there.

PS.  I will also be on a panel on Engineering in Fantasy & Science Fiction:  I love it when we discuss the thermodynamics of magic & the magic of engineering!

And a followup:

Followed Tom Holtz at Capclave:  this is always good & bad:  good because it guarantees a nice crowd, bad because he is a hard act to follow.  The assembled multitude was enthusiastic, always nice.

And the panel on engineering in F & SF also went well:  Fran Wilde did a great job moderating, had a good supply of questions & made sure everything had a whack at each, so not the usual domination by 2 or 3 of the more talky types. Audience lively (in a good way, not in the hurled rutabagas way.)

StarGate to Baltimore Opening in Six Days!

Beware of Unexpected Doors!

Call them Stargates, Jumpgates, Fargates, Hypergates or just an invitation to every unwanted pest from the far reaches of the Galaxy to visit, they are absolutely necessary if we are to have the glorious Science Fiction action we desperately need.  Could they actually be built?  Modern physics may permit, but: how to glue black holes together to build a wormhole, how to avoid the dangers of spaghettification, radiation poisoning and paradox noise, and just what would it take to build one in practice?

I’ve just finished revising my StarGates — the theory & practice — for Balticon. It’s a Good News/Bad News thing: Bad News: we don’t know how to build them, Good News: we can’t prove we can’t, someday!¹⁾(Or is that Good News:  they can’t get to us yet, Bad News:  but they just might anyway.

Slides for talk now up on SlideShare; comments & questions very welcome.

Talk will be this coming Saturday, May 27, 9am at Balticon. If in the neighborhood, drop by. If not in the neighborhood, spin up a stargate & jump in!

Invisibility, Anti-gravity, Ethics of Time Travel, & Balonium

I’ve just received my schedule for Philcon, being held in a bit over a week, November 8th thru 10th.  Curious collection of subjects, but looks like a lot of fun.  If you are in the Philly area, it would be great if you can come by!

Sat 1:00 PM in Crystal Ballroom Two (1 hour)

THE INVISIBILITY CLOAK (1553)

[Panelists: John Ashmead (mod)]

How do we hide a jet fighter, a tank, even a city from sight? For
millennia people have dreamt of invisibility rings, caps, & cloaks:
how close are we to Harry Potter territory? Progress in the last ten
years has been extraordinary, and, with some help from general
relativity, 3d printers, advanced photonics, and more than a pinch
of ingenuity, we can now bend, fold, & spindle light in ways
unimagined ten years ago
Sat 3:00 PM in Crystal Ballroom Two (1 hour)
A WEIGHTY MATTER: ANTI-GRAVITY AND ARTIFICIAL GRAVITY (1404)

[Panelists: John Ashmead (mod), Ed Bishop, Walter F. Cuirle, Jay
Wile]

Both creating and negating gravity are very common tropes in science
fiction. It’s taken for granted in most Science Fiction that
spacecraft have normal gravity, although they do not spin. How this
is achieved is rarely discussed. Anti-gravity is nearly as common,
(and convenient for the plot).. Are either of these concepts
scientifically plausible? Could such a technology ever actually be
achieved

Sat 6:00 PM in Plaza II (Two) (1 hour)
THE ETHICS OF TIME TRAVEL (1501)

[Panelists: John Ashmead (mod), Evelyn Leeper, Andrew C. Ely]

Everyone talks about killing Hitler in his crib, or stopping Booth
from shooting Lincoln. But if you could change the past, would you
Sat 7:00 PM in Plaza III (Three) (1 hour)
BALONIUM, UNOBTAINIUM AND UPSIDASIUM (1530)

[Panelists: John Ashmead (mod), Darrell Schweitzer, John Monahan,
Sharon Lee]

From cavorite to kryptonite, science fiction fiction writers love to
add new elements to the periodic table. How do you create
convincing imaginary substances and what do you do with them

Talks now on Slideshare

I’ve uploaded a number of my more recent talks to Slideshare.  Physics, with occasionally a wee bit of speculation admixed:

1. Thought experiments – talk done 1st April 2012 for the Ben Franklin Thinking Society.  Role of thought experiments in history, use by Galileo & by noted violinist, how they can turn into real experiments.
2. Not Your Grandfather’s Gravity – done last year (2011) on the latest developments in the suddenly hot area of gravity.  The stuff on faster-than-light neutrinos is, alas, already out of date:  boring won:  looks as if the FTL neutrinos were due to experimental error.   But Verlinde’s entropic gravity is still one of the most promising lines of attack.
3. Temporal Paradoxes – physics talk given at NASA’s Goddard Space Center 2011.  A slightly NASA-fied version of a talk I’d given at several SF conventions in 2010.
4. Quantum time – physics talk given at Feynman Festival in Olomouc in 2009.  I did popular versions of that talk as well.
5. How to build a (real) time machine – talk given at several SF conventions in 2009.
6. Life, the Universe, & the Second Law of Thermodynamics.  Or, the Infinite Probability drive.  About the role of entropy in the universe, complete with Babelfish.  2008.
7. Faster Than Light – talk on faster than light travel:  theory, practice, applications. Given at several SF conventions in 2007.
8. Confused at a Higher Level – arguably one of the funniest talks ever given about problems in quantum mechanics. OK, competition not that fierce.  Given at several SF conventions in 2004.
9. The Physics of Time Travel.  Review of time, with respect to the bending, stretching, folding, & tormenting thereof.  Given at Philcon & Balticon (in various versions) in 2003.
10. The Future of Time Travel – mostly about the science fiction thereof.  Probably 2002.

These are not all of my talks — I’ve probably done 20 or 30 SF talks over the last 20 years, at least one per year — these are just the ones done using Keynote or Powerpoint.  The 2005 & 2006 talks have gone walkabout.  If they reappear, I will upload.  I generally talk at Balticon, Philcon, & more recently Capclave.  I’ve spoken twice at Farpoint, but that is really more of a media convention, not as good a fit.

Other talk(s), marginally less speculative:

1. Overview of Backbone – talk on the jQuery library Backbone, given at PhillyCoders. April 2012.
2. How to Destroy a Database – talk on database security.  October 2007.  Wile E. Coyote & other experts on correctness & security are enlisted to help make key points.
3. Getting started with MySQL – talk given at PACS and my Macintosh programming group in 2006. Manages to work in the Sumerians, the Three Stooges, a rocket-powered daschhund, some unicorns, and – of course – dolphins (the totem animal of MySQL).

Not Your Grandfather’s Gravity – 3rd time is the charm

I did this talk — basically interesting developments in gravity & related subjects — for the third time at Philcon this last Saturday.  The talk was scheduled for 1pm, so I spent a few hours in the morning refreshing it.

The big news was that the OPERA project had done a second version of the experiment that saw superluminal neutrinos, dealing with some of the objections (objectinos?) to their first results.  They sacrificed quantity of neutrinos to quality:  going from 16,000 to 20, but getting much tighter time resolution.   This made the New York Times Saturday morning, so I clipped the headline for use in a slide.  Good stuff, but of course everyone wants to see Fermilab & others reproduce the experimental results.

However the combination of refreshing the talk, roadwork on Interstate 76, & a parade or some such on the Benjamin Franklin Parkway meant I got in with no time to check the AV setup before the talk.  While the impromptu AV crew wrastled the difficulties into submission (thanks Margaret Trebling, Jay Wile, Ron Bushyager, & Ferne Welch!) I invited the audience to “open the theater of your mind” & painted word pictures thereon till the AV was working.  Didn’t take the crew long:  we hadn’t even gotten past the Black Death slide before we had light!  Actually I think the difficulties may have helped the talk go over; shared troubles create bonding between speaker & audience.  Lots of good questions; SRO crowd.

As I promised then, I have posted the talk as Keynote, PDF, PowerPoint, & HTML.  Comments, questions, and suggestions very welcome!

Had a lot of fun on the six panels I was on; will post on them over the next few days.

11/23/2011 I’ve just updated the references page to include the references from the talk.

“Not Your Grandfather’s Gravity” at the Philadelphia SF Convention

I’ll be doing my Not Your Grandfather’s Gravity talk this coming Saturday at Philcon at 1pm.   I’ve been scheduled for six panels as well, five as moderator.  These are on Fiction of China Mieville, Alien Life in the Solar System (besides us), Future War, Tapping the Quantum Foam (entertaining nonsense:  crank up the balonium generators), What Makes H. P. Lovecraft Unstoppable (ph’nglui mglw’nafh Cthulhu R’lyeh wgah’nagl fhtagn), and Dark Matter gets Darker.

Full schedule:

Fri 8:00 PM in Plaza V (Five) (1 hour)
THE FICTION OF CHINA MIEVILLE (771)

   [Panelists: John Ashmead (mod), Meredith Schwartz, Andrew C. Murphy]

   Exploring the work of the popular author of Perdido Street Station
   and others.  What makes his work so special

Sat 12:00 PM in Crystal Ballroom Two (1 hour)
ALIEN LIFE IN THE SOLAR SYSTEM (848)

   [Panelists: John Ashmead (mod), Alexis Gilliland, Eric Kotani]

   Making up planets around stars we do not know is relatively easy.
   Let's talk about a more difficult approach... imagining alien
   lifeforms in the solar system as we now know it

Sat 1:00 PM in Plaza III (Three) (1 hour)
NOT YOUR GRANDFATHER'S GRAVITY (890)

   [Speaker: John Ashmead]

   Einstein's theory of gravity is our best to date -- even though it
   is known to be incomplete. Now it is in the crosshairs! Several
   competitors -- string theory, loop quantum gravity, emergent gravity
   -- have come out in the open & it's a horse race! We'll look at
   weird twists of space & time, dark energy, neutrinos just spotted
   going faster than light, the curiously shy Higgs particle, & the
   whole universe from its birth in the Big Bang to its death -- &
   possible rebirth

Sat 7:00 PM in Plaza II (Two) (1 hour)
FUTURE WAR (748)

   [Panelists: Alexis Gilliland (mod), John Ashmead, Amy Bailey, Frank
   O'Brien]

   It's commonly said among Air Force officers today that the last
   human fighter pilots have been born. Drones and remotely-piloted
   planes are the future of air warfare. What about the other branches
   of the armed forces? Robots are filling more and more roles. Will
   there come a point where there are few or no human soldiers? What
   are the implications? Is this a good or bad development

Sat 8:00 PM in Plaza V (Five) (1 hour)
TAPPING THE QUANTUM FOAM: CAN "ZERO POINT" ENERGY EVER BE REAL? (902)

   [Panelists: John Ashmead (mod), Jay Wile, Marvin Kaye]

   Infinite free energy drawn from the quantum vacuum - con games and
   pseudoscience today. But does our present understanding of quantum
   physics suggest it could ever become reality? Would the process pose
   any dangers

Sat 10:00 PM in Plaza III (Three) (1 hour)
WHAT MAKES H.P. LOVECRAFT UNSTOPPABLE? (826)

   [Panelists: John Ashmead (mod), James Chambers, Chris Pisano,
   Darrell Schweitzer, Eric Avedissian, Roman Ranieri]

   Great writers, we contend, are the ones the critics cannot stop.
   Major critics, notably Edmund Wilson, tried, but to no avail. Today
   Lovecraft is famous world-wide.  Yet when he died in 1937, his only
   published book was a wretchedly amateur production which had barely
   sold a hundred copies.  What made the difference?  Was it all those
   role-playing games and plish Cthulhu toys? The movies? Or something
   inherent in the texts

Sun 1:00 PM in Plaza V (Five) (1 hour)
DARK MATTER GETS DARKER: NEW DISCOVERIES, NEW MYSTERIES (904)

   [Panelists: John Ashmead (mod), Paul Halpern, Jay Wile, Eric Kotani]

   Dark matter detection experiment CoGeNT has seen a possible signal,
   similar to the much-disputed DAMA/LIBRA result, that might confirm
   the controversial claim that dark matter has not only been observed,
   but that it varies with the seasons. Meanwhile the XENON100 detector
   has just released results from its most recent rum: they don’t see
   anything. 

   Are we closing in on dark matter, or is it getting more mysterious?

Not your grandfather’s gravity redux at Capclave

I’m doing “Not Your Grandfather’s Gravity” this evening at Capclave:  had to revise a lot:  added in the superluminal neutrinos from the OPERA project, the curious incident of the Higgs particle detection, and the Nobel just given out for Dark Energy:  half the slides changed!  PDF, HTML.

I’m also doing panels on Hard SF & Alien Cultures, Making Fictional Cities Come Alive (when real ones do, run!), and Astronomy & Science Fiction.  If you are in the DC area, I look forward to seeing you.

Gravity unexpectedly popular, levity suspected

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