Clever Experiment on Single Atoms Advances Understanding of Dark Matter

Atom Interferometer

This is the atom interferometer. Credit: Imperial College London

An experiment to test a popular theory of dark energy has found no evidence of new forces, placing strong constraints on related theories.

Dark energy is the name given to an unknown force that is causing the universe to expand at an accelerating rate.

Some physicists propose dark energy is a ‘fifth’ force that acts on matter, beyond the four already known – gravitational, electromagnetic, and the strong and weak nuclear forces.

However, researchers think this fifth force may be ‘screened’ or ‘hidden’ for large objects like planets or weights on Earth, making it difficult to detect.

Now, researchers at Imperial College London and the University of Nottingham have tested the possibility that this fifth force is acting on single atoms, and found no evidence for it in their most recent experiment.

This could rule out popular theories of dark energy that modify the theory of gravity, and leaves fewer places to search for the elusive fifth force.

Finding the fifth force

The experiment, performed at Imperial College London and analyzed by theorists at the University of Nottingham, is reported in Physical Review Letters.

Professor Ed Copeland, from the Centre for Astronomy & Particle Physics at the University of Nottingham, said: “This experiment, connecting atomic physics and cosmology, has allowed us to rule out a wide class of models that have been proposed to explain the nature of dark energy, and will enable us to constrain many more dark energy models.”

The experiment tested theories of dark energy that propose the fifth force is comparatively weaker when there is more matter around – the opposite of how gravity behaves.

This would mean it is strong in a vacuum like space, but is weak when there is lots of matter around. Therefore, experiments using two large weights would mean the force becomes too weak to measure.

Experiment with a single atom

The researchers instead tested a larger weight with an incredibly small weight – a single atom – where the force should have been observed if it exists.

The team used an atom interferometer to test whether there were any extra forces that could be the fifth force acting on an atom. A marble-sized sphere of metal was placed in a vacuum chamber and atoms were allowed to free-fall inside the chamber.

The theory is, if there is a fifth force acting between the sphere and atom, the atom’s path will deviate slightly as it passes by the sphere, causing a change in the path of the falling atom. However, no such force was found.

Professor Ed Hinds, from the Department of Physics at Imperial, said: “It is very exciting to be able to discover something about the evolution of the universe using a table-top experiment in a London basement.”


Reference: “Experiment to Detect Dark Energy Forces Using Atom Interferometry” by D. O. Sabulsky, I. Dutta, E. A. Hinds, B. Elder, C. Burrage, and Edmund J. Copeland, 6 August 2019, Physical Review Letters. DOI: 10.1103/PhysRevLett.123.061102

10 Comments on "Clever Experiment on Single Atoms Advances Understanding of Dark Matter"

  1. Robert Paradis | August 26, 2019 at 5:42 pm | Reply

    My theory shows that gravity is due to matter not participating to the expansion. Thus, it is not possible to find something else than gravity when looking at matter behaviour. The entire Universe exists under, by the expansion principal.

  2. I can see dark energy/matter.
    You should contact me.
    I have a rare gift, into seeing things others can not.
    Amuse yourself and contact me.
    I see translucent things.

  3. Dark energy and fifth forces can be found if we can prove how the ancient Egyptians easily lifted heavy loads like Obelisks and continuously built massive pyramids one after the other for many centuries. How they planned such massive edifices in the lifetime of a Pharaoh for which the common man had no use. Surely they overcame gravity with an anti gravity force not manual force. If this can be discovered it will give headstart to the discovery of dark energy.

  4. John Abraham, are you feeling OK?

  5. And now we’re down to mystery forces that only affect things smaller than an atom. Like a single electron , or wait, electrons are made up of pieces as well , aren’t they ? A single one of those pieces …etc etc…

  6. John Abram…pyramids

    They did it with big rocks on logs , lots and lots of slave labor, lots and lots of beatings and fatalities, and teh logs rotted away leaving only pyramids made out of stones.

    At least challenge us with a mystery that hasn’t already been solved long ago.

  7. I am squarely in the Einstein camp that Gravity and its time equivilent (Graviton and Tachyon) simply don’t exist – both Gravity and Expansion of spacetime can be explained using curvature of space and time dimensions.

    I believe the standard forces (electromagnetic, weak and strong) as well as all the electron and quark charged particles can be explained using 7D gauge theory. However it has 3 x space dimensions and 4 time-like dimensions (1 for electric charge, 3 for coloured charges). This gives us why electrons have only up/down, but quarks have up/down and colour. W+/- bosons are also timelike and 1/2 electric charge and 1/2 strong colour.

    Now we can imagine outside the 7D box. That is vacuum energy and beyond that is the realm of dark matter and dark energy (made up of the same electromagnetic, weak and strong forces – just not in the same dimensions of space and time as matter).

    They all work on the diagonal determinant of the gauge array – and that is where the curvature comes in, acceleration in space minus acceleration in time gives net mass, negative mass (ala dark energy) is simply accelerating in the time dimensions more than space dimensions.

    Space is a positive curvature parabolic shape, time is negative curvature hyperbolic shape, charges exist inbetween them (so saddle shaped). The universe is not flat – it is a mix of parabolic, hyperbolic and saddle shaped. So dark energy is like a concave lens, dark matter and mass like convex lens – and the determinant of the array is the net effect of charges and fields on the dimensions.

    Klein-Gordon equation is actually showing the net acceleration – which defines its mass (which is the centerpoint / rest frame, between what is space acceleration and time acceleration).

    I have attached the link to the image showing the 7D gauge – Orange=Photons, Green=Fermions (3×1=Electron, 3×3=Quarks), Puple=(3×1 W+/-, 3×3=Gluons). Electrons only have electric charge, quarks only colour charge, both share space and the photons. Gluons and W+/- are time like particles though (only exist in time dimensions NOT space as the photons do).

    Diagonal (spacetime) is now (x^2+y^2+z^2 magnetic) – (t^2 electric) – (r^2+g^2+b^2 strong). W+/- and Z are what link electric and strong time dimensions. However for gravity – we are only interested in the spacelike acceleration, the timelike acceleration acts like anti-gravity and is why gravity is far weaker than the other forces.

  8. Our “Beginnings” was a *Creation event; which Continues…
    The mass of the universe is increasing;
    More matter, more gravity ‘out there’ makes for a stable, expanding space-time continuum in our neighborhood.

    The Big Bang: GOD spoke, and has never called His Word back…Blessed is the Name of the LORD!

  9. Jason P Jackson | August 28, 2019 at 4:24 pm | Reply

    It may be due to a second big bang traveling towards us. Or an alien monster. These pertinent hypotheses are yet to be ruled out.

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