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Ken Bloom | USLHC | USA

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Theory and experiment come together — bazinga!

Regular readers of Quantum Diaries will know that in the world of particle physics, there is a clear divide between the theorists and the experimentalists. While we are all interested in the same big questions — what is the fundamental nature of our world, what is everything made of and how does it interact, how did the universe come to be and how might it end — we have very different approaches and tools. The theorists develop new models of elementary particle interactions, and apply formidable mathematical machinery to develop predictions that experimenters can test. The experimenters develop novel instruments, deploy them on grand scales, and organize large teams of researchers to collect data from particle accelerators and the skies, and then turn those data into measurements that test the theorists’ models. Our work is intertwined, but ultimately lives in different spheres. I admire what theorists do, but I also know that I am much happier being an experimentalist!

But sometimes scientists from the two sides of particle physics come together, and the results can be intriguing. For instance, I recently came across a new paper by two up-and-coming physicists at Caltech. One, S. Cooper, has been a noted prodigy in theoretical pursuits such as string theory. The other, L. Hofstadter, is an experimental particle physicist who has been developing a detector that uses superfluid liquid helium as an active element. Superfluids have many remarkable properties, such as friction-free flow, that can make them very challenging to work with in particle detectors.

Hofstadter’s experience in working with a superfluid in the lab gave him new ideas about how it could be used as a physical model for space-time. There have already been a number of papers that posit a theory of the vacuum as having properties similar to that of a superfluid. But the new paper by Cooper and Hofstadter take this theory in a different direction, positing that the universe actually lives on the surface of such a superfluid, and that the negative energy density that we observe in the universe could be explained by the surface tension. The authors have difficulty generating any other testable hypotheses from this new theory, but it is inspiring to see how scientists from the two sides of physics can come together to generate promising new ideas.

If you want to learn more about this paper, watch “The Big Bang Theory” tonight, February 5, 2015, on CBS. And Leonard and Sheldon, if you are reading this post — don’t look at the comments. It will only be trouble.

In case you missed the episode, you can watch it here.

Like what you see here? Read more Quantum Diaries on our homepage, subscribe to our RSS feed, follow us on Twitter, or befriend us on Facebook!

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  • I have been enjoying both Quantum Diaries and The Big Bang Theory for quite a while, I was delighted when you guys cane up in tonight’s show. It reminded me of the time a Perimeter Institute posting was on the wall of their cafeteria. Very cool those who produce the program and watch over its content.

  • I am just watching this fun episode and it’s cool. Of course, trying to look at the idea seriously. One thing I don’t quite get is what “negative energy density” they and you are talking about. The energy density is surely positive by the positive energy theorems and energy conditions, right? And even the cosmological constant is positive in Nature which means a positive energy density combined with negative pressure. Is the negative pressure what you meant?

    If there is some superfluid “beneath”, isn’t the model just a braneworld scenario with us on the end-of-the-world brane, like Hořava-Witten or some kind of Randall-Sundrum? What is the added value resulting from the superfluid idea relatively to the HW or RS description?

  • Prof Fingleheimer

    Hi Luboš,
    I haven’t absorbed all of the CH paper yet, but the negative energy density shows up their section where they are making calculations about the Casimir Effect-like properties, so that would be a likely reason for it. But I’m no theorist. I’ll let others weigh in on the relative merits for HW and RS.

    David Saltzberg

  • Emanuel Hoogeveen

    Not a fan of the show, but more power to you for trying to make it more scientific.

  • Zephir

    The Aether wave theory based on dense aether model uses the water surface analogies often. In particular, the Hubble red shift is an analogy of scattering of water ripples with density fluctuations of the underwater in it. The gravity is the result of shielding of longitudinal waves, the Cassimir force is the result of shielding of transverse waves of massive bodies, the photons are analogy of the Russels and neutrinos Falaco solitons at the water surface, etc.

    Arthur Schopenhauer: “All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident”.

  • Amogh Gudi

    I think they meant vacuum energy density.

  • Right, I know they did and they surely did but the vacuum energy density in our Universe is positive, not negative.

  • Brad Slucher

    The analogy between super cooled fluid and space time is either meaningless or false. I wish this blog would devote itself to real science instead of wasting our time with crackpot, wannabe theoreticians that are in a rush to publish.

  • Brad Slucher

    Upon review, i have changed my mind about the Cooper-Hofstadter hypothesis that space time is like super cooled fluid. In fact it has inspired me to write my own hypothesis. Maybe space time is like two clowns with their heads in a bucket much like Cooper and Hofstadter.

  • GeneralRelativity

    Upon review, I have changed my mind about the Cooper-Hofstadter hypothesis that space-time is like a superfluid. In fact, it’s inspired me to come up with my own theory. Maybe space-time is like two clowns with their heads in a bucket much like Cooper and Hofstadter.

  • John L. Lee

    When ya’ll stop tryin’ to shove yer ideas into a box, ya begin ta see outside da box! The biggest impediment to scientific advancement is lack of imagination!

  • DoCDow

    Universe actually lives on the surface of a surface,,Michelson was Warm !

  • DoCDow

    Two Physicists walk into a bar, with a full plastic trash bag each. Found on the curb on there way to meet .One says to the other lets Collide them at 70,000 MPH

  • Kim in media space

    I am a fan of the show. I thought The Troll Manifestation episode was especially intriguing et voilà here I am reading up on the Casimir Effect. Cool!
    Cheers.

  • The Werewolf

    Except that the universe has a base energy level which is sometimes called the ‘zero point’ energy level (Amogh’s vacuum energy density). This is what drives things like virtual particle production in ’empty’ space (or better in the quantum foam).

    You could have region of spacetime where the local energy is lower than the base. From the perspective of the universe, it would appear to be a region of space with negative energy.

  • The Werewolf

    Amigo – wait until you take a gander at the idea that the universe is a holographic image held on the event horizon of a supermassive black hole. Now, here’s the question – can the inside of an event horizon be described as a superfluid?

    For that matter – can the inside of your head be described as a superfluid? 🙂

  • Right, you may choose the vacuum energy density (which is positive in our Universe, due to the cosmological constant) as the base level, and “negative energy density” is then the term for anything lower than the vacuum energy density.

    But exactly this “negative energy density” is never allowed, at least not a finite energy density separated from zero in a macroscopic region of space. If it were possible to lower the energy in the region in this way, the original region wouldn’t have been a vacuum, by definition, and it would have been unstable, by dynamics.

  • It is not a superfluid, there is an all encompassing string particle field (not the string theory type) in space (and everywhere).
    The field is made from individual yet connected particles and conforms to whatever shape it is surrounding. So light traveling through a curved field (like the Earth or Sun) will of course curve.
    Is gravity curving the field? No! The field itself is what creates gravity (gravity is field tension).
    Does this invalidate any of Einsteins equations? Of course not, it is just another way to look at it. Einstein has field equations and this is the field.
    The particles are connected — that creates a field. The field has tension on it so vibrations can easily travel through it on the strings .
    That’s what light is…
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    WHY THE SPEED OF LIGHT IS “C”
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    There is a high tension string particle field in space (not the string theory type). Everything is connected by the particle field and it moves along with largest mass in proximity (something like what gravitational fields would be doing. the Earth is not rushing through the field — that would be complete stupidity to think that).
    A good 2-D model would be something like a spiders web (individual string lengths are approximately one Ångström).
    Now imagine an infinite 3-D spiders web. If a vibration was set off in it, it would travel forever and the speed the vibrations travel (through the net) is the speed of light (that’s actually what light is, a vibration traveling through a string particle field)
    The speed vibrations travel through the particle field is the speed of light “c”

    The particle field strings have a certain amount of tension, length and mass. That makes ‘c’ the speed it is. If the tension, length or mass changed so would ‘c’

    Here is a regular string tension formula…

    Tension = velocity squared x mass / Length.

    If we plug c in and rearrange we get…
    TL = mc^2

    Both sides of the equation are in joules or energy… equivalent to “E”.
    It means the Tension of the strings in space times their length is equal to their energy.

    This is why the speed of light is involved in Einsteins mass energy equivalence equation…

    E = mc^2

    …and actually why light travels at the speed of light…
    I always wondered why… now I know.
    It had to be something mechanical… tension and string lengths!

    So, you can arrive at Einsteins famous formula from completely different directions.
    You can think energy is contained in mass and released.

    E = mc^2

    Or you can think there is a particle field of strings and mass is inert, the energy is only potential… released (actually pulled) by tension on the strings.

    TL = mc^2

    They are equivalent. Which is correct? You do not know.

    Tesla was correct…
    “There is no energy in matter other than that received from the environment.” – Nikola Tesla

  • Tension is the correct idea but It is not happening in a superfluid — there is an all encompassing string particle field (not the string theory type) in space (and everywhere).
    The field is made from individual yet connected particles and conforms to whatever shape it is surrounding. So light traveling through a curved field (like the Earth or Sun) will of course curve.
    Is gravity curving the field? No! The field itself is what creates gravity (gravity is field tension).
    Does this invalidate any of Einsteins equations? Of course not, it is just another way to look at it. Einstein has field equations and this is the field.
    The particles are connected — that creates a field. The field has tension on it so vibrations can easily travel through it on the strings .
    That’s what light is…
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    WHY THE SPEED OF LIGHT IS “C”
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    There is a high tension string particle field in space (not the string theory type). Everything is connected by the particle field and it moves along with largest mass in proximity (something like what gravitational fields would be doing. the Earth is not rushing through the field — that would be complete stupidity to think that).
    A good 2-D model would be something like a spiders web (individual string lengths are approximately one Ångström).
    Now imagine an infinite 3-D spiders web. If a vibration was set off in it, it would travel forever and the speed the vibrations travel (through the net) is the speed of light (that’s actually what light is, a vibration traveling through a string particle field)
    The speed vibrations travel through the particle field is the speed of light “c”

    The particle field strings have a certain amount of tension, length and mass. That makes ‘c’ the speed it is. If the tension, length or mass changed so would ‘c’

    Here is a regular string tension formula…

    Tension = velocity squared x mass / Length.

    If we plug c in and rearrange we get…
    TL = mc^2

    Both sides of the equation are in joules or energy… equivalent to “E”.
    It means the Tension of the strings in space times their length is equal to their energy.

    This is why the speed of light is involved in Einsteins mass energy equivalence equation…

    E = mc^2

    …and actually why light travels at the speed of light…
    I always wondered why… now I know.
    It had to be something mechanical… tension and string lengths!

    So, you can arrive at Einsteins famous formula from completely different directions.
    You can think energy is contained in mass and released.

    E = mc^2

    Or you can think there is a particle field of strings and mass is inert, the energy is only potential… released (actually pulled) by tension on the strings.

    TL = mc^2

    They are equivalent. Which is correct? You do not know.

    Tesla was correct…
    “There is no energy in matter other than that received from the environment.” – Nikola Tesla

  • ~~~~~~~~~~~~~~~~
    VACUUM OF SPACE
    ~~~~~~~~~~~~~~~~

    Space is not a vacuum, it is normal, we are under pressure.
    also… I’m sure the vacuum energy of (actually non) empty space is not a vacuum, it is tension on the field of strings (not the string theory type) . I would bet my life on it.

    It also explains (what they call) Dark Energy… everything is being pulled on (not pushed) equally from every direction (coming from infinity).
    If there are two end points (any type of matter, planets or anything) that creates a stronger connection and they pull together — that’s gravity.