Search FQXi


If you are aware of an interesting new academic paper (that has been published in a peer-reviewed journal or has appeared on the arXiv), a conference talk (at an official professional scientific meeting), an external blog post (by a professional scientist) or a news item (in the mainstream news media), which you think might make an interesting topic for an FQXi blog post, then please contact us at forums@fqxi.org with a link to the original source and a sentence about why you think that the work is worthy of discussion. Please note that we receive many such suggestions and while we endeavour to respond to them, we may not be able to reply to all suggestions.

Please also note that we do not accept unsolicited posts and we cannot review, or open new threads for, unsolicited articles or papers. Requests to review or post such materials will not be answered. If you have your own novel physics theory or model, which you would like to post for further discussion among then FQXi community, then please add them directly to the "Alternative Models of Reality" thread, or to the "Alternative Models of Cosmology" thread. Thank you.

Forum Home
Introduction
Terms of Use

Order posts by:
 chronological order
 most recent first

Posts by the blogger are highlighted in orange; posts by FQXi Members are highlighted in blue.

By using the FQXi Forum, you acknowledge reading and agree to abide by the Terms of Use

 RSS feed | RSS help
RECENT POSTS IN THIS TOPIC

John Cox: on 1/17/14 at 19:19pm UTC, wrote Tom, I think the best explanation of continuous function is still; pi. It...

Thomas Ray: on 1/17/14 at 17:58pm UTC, wrote Thanks, John R. Maybe you can use it to explain to Rob what continuous...

John Cox: on 1/17/14 at 17:50pm UTC, wrote Tom, Nice non technical link introductory of Solitonic wave phenomenon....

John Cox: on 1/16/14 at 16:18pm UTC, wrote "What is a Particle?" Good question. Maybe we should start with that. ...

Akinbo Ojo: on 1/16/14 at 9:41am UTC, wrote Rob, Are you a something or a somewhere or both? I will post a short...

Thomas Ray: on 1/15/14 at 19:24pm UTC, wrote I agree Rob, and "quantum aether" is fine with me. As far as the need for...

Akinbo Ojo: on 1/15/14 at 19:13pm UTC, wrote Very rational questions Rob, i.e. What are these "somethings" and...

Robert McEachern: on 1/15/14 at 19:11pm UTC, wrote "The reason that we qualify the term "vacuum" by "quantum vacuum" is...


RECENT FORUM POSTS

halim sutarmaja: "dewapoker hadir untuk semua pecinta game poker dengan teknologi terbaru dan..." in New Nuclear "Magic...

Jason Wolfe: "Hi Georgina, Steve, What is reality? The humorous answer, almost at the..." in Schrödinger’s Zombie:...

Jason Wolfe: "Joe, What you are saying sounds like mathematics. But mathematics doesn't..." in First Things First: The...

Joe Fisher: "Jason, You can only unnaturally make an infinite number of finite written..." in First Things First: The...

Jason Wolfe: "As for religious fundamentalists, I would rather deal with them, then with..." in More on agency from the...

Jason Wolfe: "The best we can do with the environment is to plant more trees and..." in More on agency from the...

gmail login: "Thanks a lot for the post. It has helped me get some nice ideas. I hope I..." in Bonus Koan: A Lake of...

Georgina Woodward: "Steve, I don't think the quantum representation of the hydrogen atom is an..." in Schrödinger’s Zombie:...


RECENT ARTICLES
click titles to read articles

First Things First: The Physics of Causality
Why do we remember the past and not the future? Untangling the connections between cause and effect, choice, and entropy.

Can Time Be Saved From Physics?
Philosophers, physicists and neuroscientists discuss how our sense of time’s flow might arise through our interactions with external stimuli—despite suggestions from Einstein's relativity that our perception of the passage of time is an illusion.

Thermo-Demonics
A devilish new framework of thermodynamics that focuses on how we observe information could help illuminate our understanding of probability and rewrite quantum theory.

Gravity's Residue
An unusual approach to unifying the laws of physics could solve Hawking's black-hole information paradox—and its predicted gravitational "memory effect" could be picked up by LIGO.

Could Mind Forge the Universe?
Objective reality, and the laws of physics themselves, emerge from our observations, according to a new framework that turns what we think of as fundamental on its head.


FQXi BLOGS
November 18, 2019

CATEGORY: Blog [back]
TOPIC: Fluctuations, Schmucuations [refresh]
Bookmark and Share
Login or create account to post reply or comment.

Blogger George Musser wrote on Jan. 14, 2014 @ 13:18 GMT
PUERTO RICO—One of my favorite talks at the recently concluded FQXi conference was Sean Carroll's takedown of the concept of quantum fluctuations in inflationary cosmology. Regardless of the fate of his overall argument—which my fellow FQXI bloggers Zeeya Merali and Ian Durham have already discussed—I think Carroll’s essential point about fluctuations is extremely important and not widely appreciated.

Whenever physicists talk about quantum mechanics, they conjure up a world gone mad. “The universe is a teeming, chaotic, frezied arena on microscopic scales,” wrote Brian Greene in The Elegant Universe. Particles squirm like kindergartners after too much circle time. Fields jitter uncontrollably. Spacetime itself tosses like a stormy sea. These are not merely images that physicists offer when simplifying their arguments for the general public. They appear in academic papers, too.

But what, exactly, is fluctuating? The usual accounts imply there is some definite reality that wavers from moment to moment. Yet most physicists eschew such a definite reality. In the orthodox interpretation of quantum theory, a particle doesn’t exist at a specific position (except in special cases). It doesn’t exist at multiple positions. It simply doesn’t have a position. As philosopher David Albert has put it, position has as much meaning for the particle as political affiliation has for a tuna sandwich. So, the particle can no sooner fluctuate in position than the sandwich could quit Occupy Wall Street and join the Tea Party.

The Schrödinger equation of quantum mechanics describes a particle or other physical system using a wavefunction. A wavefunction does not fluctuate. It evolves deterministically. The idea of a fluctuation enters when the system is measured. If the wavefunction spans multiple positions, then the particle will appear in one of those positions at random. If you prepare a series of particles in exactly the same way and then measure them one by one, they will show up in different positions. This is what physicists mean by quantum fluctuation: not the quivering of a single particle, but the spread that arises for an ensemble of identical particles. Single particles do quiver—for instance, in Brownian motion—but this is a thermal rather than a quantum effect.

You commonly hear that the vacuum is ceaselessly burbling with particles fluctuating in and out of existence. This, too, is a misconception. Rather, what happens is that a vacuum—a state of a field with zero particles—does not have a well-defined energy, but is a superposition of multiple possible energies. Every time a detector measures the energy of the field, it obtains a different value. It’s not that the field’s energy is fluctuating. It’s that the energy isn’t even properly defined.

Cosmologists invoke fluctuations all the time to explain, for example, why the process of inflation can never end. “There is a conventional wisdom,” Carroll told the FQXi meeting. “I know this because I have promulgated this conventional wisdom for years now.” And he now thinks it’s wrong. I can’t wait to see the paper he is now writing to elaborate on the implications.

Bookmark and Share
report post as inappropriate


Thomas Howard Ray wrote on Jan. 14, 2014 @ 13:47 GMT
Excellent, George!

The universe presents itself to us as metastable. Every time I hear the conventional arguments militating against this, I want to know *where* and *how* the theorists think that the quantum world smooths out into classical functions -- and I wonder anew why the community so harshly rejects Joy Christian's solution to the problem.

Tom

Bookmark and Share
report post as inappropriate

Joy Christian replied on Jan. 14, 2014 @ 14:08 GMT
Tom,

For what it's worth, I wonder that too. I think George, with his privileged position and journalistic talents, has greater responsibility here, because most scientists themselves (including myself) are too blindsided by their own commitments to various ideologies.

Joy

Bookmark and Share
report post as inappropriate

Thomas Howard Ray replied on Jan. 14, 2014 @ 14:44 GMT
That's a good point, Joy. I started as a journalist many years ago and rejected that career, ironically, for the same reasons that you assign to ideologically hobbled scientists.

I am at the point of seeing that it takes real work to be objective. Is it worth it? -- only if science is to remain a rationalist enterprise, and we are committed to the idea that personality cults are bad for science.

Tom

Bookmark and Share
report post as inappropriate


Robert H McEachern wrote on Jan. 14, 2014 @ 13:55 GMT
" "...I have promulgated this conventional wisdom for years now." And he now thinks it's wrong. I can't wait to see the paper he is now writing to elaborate on the implications. "

You don't have to wait. Read my 2012 FQXI essay.

Rob McEachern

Bookmark and Share
report post as inappropriate


Member Sabine Hossenfelder wrote on Jan. 14, 2014 @ 15:14 GMT
One can mystify the situation further by noting that 'particle' isn't well-defined either...

Bookmark and Share
report post as inappropriate

Thomas Howard Ray replied on Jan. 14, 2014 @ 15:46 GMT
Very true, Bee. There are first principles -- e.g., Newton's inverse square law which applies equally to gravity and electromagnetism -- to describe changing field strength relations.

From what first principle is 'particle' derived?

Bookmark and Share
report post as inappropriate

Akinbo Ojo replied on Jan. 14, 2014 @ 19:17 GMT
To George, Tom, John, Rob, Sabine and any other who want to better know and define what a 'particle' is, first hearken to Galileo's advice: “He who attempts natural philosophy without geometry is lost” - Galileo Galilei, Dialogo, Opere 7 299 (Edizione nazionale, Florence, 1890-1909), then read the first few paragraphs of Leibniz's Monadology with a modern eye (not frog or bird), then finally consider Max Tegmark's argument "I argue that it means that our universe isn't just described by math, but that it is math in the sense that we're all parts of a giant mathematical (better to say "geometric") object, which in turn is part of a multiverse so huge that it makes the other multiverses debated in recent years seem puny in comparison" but instead of Max looking outwards for Multiverses look very deep inwards for Miniverses, if possible up to the Planck limit. You may just find that in some sense a particle is a miniverse.

Regards,

Akinbo

Bookmark and Share
report post as inappropriate

Thomas Howard Ray replied on Jan. 15, 2014 @ 14:20 GMT
Akinbo, Sabine, et al:

There has been at least 30 years of research into the properties of superconductive elements and the possible relation of soliton waves to the phenomenon -- research with which Bee is likely intimately familiar.

Pertinent to the "what is a particle?" question:

"'It brings us into a new conceptual domain of what a particle is,'' said Robert Schrieffer of the University of California at Santa Barbara, who shared the Nobel Prize for creating the 30-year-old theory of superconductivity now being superceded. 'Usually you think of starting out with bare particles in a vacuum and putting them into a medium. The soliton is a wrinkle of the medium itself. It's self-focusing, and it just doesn't dissipate.' Close to Perpetual Motion."

And

"Understanding why solitons arise in nature has been a challenge not only for physics but also for mathematics. They are leading examples of the kind of orderly structures that can arise only in nonlinear systems, systems that cannot be expressed in terms of simple, proportional relationships and are therefore notoriously hard to unravel."

The mathematical technique of Joy Christian -- using a topological framework to describe ordered relations from nonlinear phenomena -- is a far more general result than the critics, who do not comprehend topology and continuous measurement functions, have yet to realize.

Tom

Bookmark and Share
report post as inappropriate


Peter Warwick Morgan wrote on Jan. 14, 2014 @ 17:40 GMT
"Every time a detector measures the energy of the field, it obtains a different value." If the detector you are using is really an energy measurement device, and the state you are measuring is really the vacuum state, the value returned will always be zero (or, at least, a constant value). OTOH, there are other measurement observables for which we would expect a non-zero variance in the vacuum state, both for the free field and for interacting fields, despite the vacuum state being the (or a) minimum energy state. Better, perhaps, to say something like "measurement result A has non-zero variance" than to say that "X is fluctuating".

Bookmark and Share
report post as inappropriate


John Brodix Merryman wrote on Jan. 14, 2014 @ 17:57 GMT
Is the tide turning? Will there start to be a review of premises and not just ever more speculation to support current theory?

Tom,

"From what first principle is 'particle' derived?"

Probably the dimensionless point.

Regards,

John M

Bookmark and Share
report post as inappropriate

Thomas Howard Ray replied on Jan. 14, 2014 @ 18:22 GMT
You think a dimensionless point is a particle?

Bookmark and Share
report post as inappropriate

John Brodix Merryman replied on Jan. 14, 2014 @ 18:55 GMT
Tom,

No, I think it is the principle of the relative point location which helps to validate the usefulness of the idea of the particle as a fundamental feature of reality. It might well be a perfectly useful and valid conceptual connection, but I was simply trying to answer your question as to the first principle(or axiom) from which the particle concept is derived.

Regards,

John M

Bookmark and Share
report post as inappropriate

Thomas Howard Ray replied on Jan. 14, 2014 @ 19:20 GMT
You would define a particle as a point set, then?

Bookmark and Share
report post as inappropriate


John Brodix Merryman wrote on Jan. 14, 2014 @ 19:45 GMT
What Scientific Idea is Ready for Retirement?

Bookmark and Share
report post as inappropriate


Fred Diether wrote on Jan. 14, 2014 @ 20:02 GMT
Well... if quantum field theory is correct and we are pretty sure that it is, then if you try to confine an electron to a space much smaller than its compton wavelength, you will have provided enough energy to produce particle pairs from the quantum "vacuum". So I doubt very much that Sean Caroll's idea has much merit. Quantum fluctuations are here to stay and there is no way to get rid of them.

Bookmark and Share
report post as inappropriate

Thomas Howard Ray replied on Jan. 15, 2014 @ 12:21 GMT
Hi Fred,

Consider superconductivity, in which precisely cooperating elements behave as a discrete quantum. There is no fluctuating behavior.

There is every reason to believe that the quantum vacuum is superconductive; i.e., a pure wave state.

This actually strengthen's Joy Christian's argument, because it obviates particle behavior as primary to the foundations of reality. Then it is the geometry (i.e., extended to topology) of spacetime that determines particle behavior and not the other way around.

Best,

Tom

Bookmark and Share
report post as inappropriate

Robert H McEachern replied on Jan. 15, 2014 @ 15:22 GMT
Tom,

"There is every reason to believe that the quantum vacuum is superconductive; i.e., a pure wave state."

An interesting idea. But also rather oxymoronic. "conductive" implies that something is being conducted somewhere. What are these "somethings" and somewheres" in the vacuum?

Rob McEachern

Bookmark and Share
report post as inappropriate

Thomas Howard Ray replied on Jan. 15, 2014 @ 15:52 GMT
" ... 'conductive' implies that something is being conducted somewhere. What are these 'somethings' and 'somewheres' in the vacuum?"

Quite correct, Rob. Combining Carroll's conjecture with Joy Christian's measurement framework completely solves the problem of nonlocality, expressed by Eddington as "Something somewhere is doing we don't know what." The manifestly local quantum vacuum is not doing anything except continuously communicating (vice discontinuously imparting by fluctuation) physical wave properties to what we interpret as particle events. Joy's claim, that nonlocality is illusion, is thus substantiated.

Bookmark and Share
report post as inappropriate


John Brodix Merryman wrote on Jan. 15, 2014 @ 02:16 GMT
Quantum-to-classical transition may be explained by fuzziness of measurement references

"Here, the physicists looked at both parts of the measurement process and found that their coarsening leads to completely different outcomes. Their main result is that coarsening the measurement reference always forces the quantum-to-classical transition, while coarsening the final detection does not. This is because increasing the "macroscopicity" of the system, such as by increasing the number of photons in an entangled photon state, can make up for the coarseness of the final detection, but not for the coarseness of the measurement reference."

Read more at: http://phys.org/news/2014-01-quantum-to-classical-transition
-fuzziness.html#jCp

Bookmark and Share
report post as inappropriate


Login or create account to post reply or comment.

Please enter your e-mail address:
Note: Joining the FQXi mailing list does not give you a login account or constitute membership in the organization.