Physicists Take a New Approach to Unify Quantum Theory and Theory of Relativity

September 5, 2013


Scientists Take a New Approach to the Unification of General Theory of Relativity and Quantum Theory

Space consists of tiny elementary cells or “atoms of space” in some modern theories of quantum gravity trying to unify General Relativity and Quantum Mechanics. Quantum gravity should make it possible to describe the evolution of the universe from the Big Bang to today within one single theory. Credit: T. Thiemann (FAU Erlangen), Albert Einstein Institute, Milde Marketing Wissenschaftskommunikation, exozet effects

Physicists from the Max Planck Institute and the Perimeter Institute in Canada have developed a new approach to the unification of the general theory of relativity and quantum theory.

Present-day physics cannot describe what happened in the Big Bang. Quantum theory and the theory of relativity fail in this almost infinitely dense and hot primal state of the universe. Only an all-encompassing theory of quantum gravity which unifies these two fundamental pillars of physics could provide an insight into how the universe began. Scientists from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Golm/Potsdam and the Perimeter Institute in Canada have made an important discovery along this route. According to their theory, space consists of tiny “building blocks”. Taking this as their starting point, the scientists arrive at one of the most fundamental equations of cosmology, the Friedmann equation, which describes the universe. This shows that quantum mechanics and the theory of relativity really can be unified.

For almost a century, the two major theories of physics have coexisted but have been irreconcilable: while Einstein’s General Theory of Relativity describes gravity and thus the world at large, quantum physics describes the world of atoms and elementary particles. Both theories work extremely well within their own boundaries; however, they break down, as currently formulated, in certain extreme regions, at extremely tiny distances, the so-called Planck scale, for example. Space and time thus have no meaning in black holes or, most notably, during the Big Bang.

Daniele Oriti from the Albert Einstein Institute uses a fluid to illustrate this situation: “We can describe the behavior of flowing water with the long-known classical theory of hydrodynamics. But if we advance to smaller and smaller scales and eventually come across individual atoms, it no longer applies. Then we need quantum physics.” Just as a liquid consists of atoms, Oriti imagines space to be made up of tiny cells or “atoms of space”, and a new theory is required to describe them: quantum gravity.

Continuous space is broken down into elementary cells

In Einstein’s relativity theory, space is a continuum. Oriti now breaks down this space into tiny elementary cells and applies the principles of quantum physics to them, thus to space itself and to the theory of relativity describing it. This is the unification idea.

A fundamental problem of all approaches to quantum gravity consists in bridging the huge dimensional scales from the space atoms to the dimensions of the universe. This is where Oriti, his colleague Lorenzo Sindoni and Steffen Gielen, a former postdoc at the AEI who is now a researcher at the Perimeter Institute in Canada, have succeeded. Their approach is based on so-called group field theory. This is closely related to loop quantum gravity, which the AEI has been developing for some time.

The task now consisted in describing how the space of the universe evolves from the elementary cells. Staying with the idea of fluids: How can the hydrodynamics for the flowing water be derived from a theory for the atoms?

This extremely demanding mathematical task recently led to a surprising success. “Under special assumptions, space is created from these building blocks, and evolves like an expanding universe,” explains Oriti. “For the first time, we were thus able to derive the Friedmann equation directly as part of our complete theory of the structure of space,” he adds. This fundamental equation, which describes the expanding universe, was derived by the Russian mathematician Alexander Friedman in the 1920s on the basis of the General Theory of Relativity. The scientists have therefore succeeded in bridging the gap from the microworld to the macroworld, and thus from quantum mechanics to the General Theory of Relativity: they show that space emerges as the condensate of these elementary cells and evolves into a universe which resembles our own.

Quantum gravity could now answer questions regarding the Big Bang

Oriti and his colleagues thus see themselves at the start of a difficult but promising journey. Their current solution is valid only for a homogeneous universe – but our real world is much more complex. It contains inhomogeneities, such as planets, stars and galaxies. The physicists are currently working on including them in their theory.

And they have planned something really big as their ultimate goal. On the one hand, they want to investigate whether it is possible to describe space even during the Big Bang. A few years ago, former AEI researcher Martin Bojowald found clues, as part of a simplified version of loop quantum gravity, that time and space can possibly be traced back through the Big Bang. With their theory, Oriti and his colleagues are hoping to confirm or improve this result.

If it continues to prove successful, the researchers could perhaps use it to explain also the assumed inflationary expansion of the universe shortly after the Big Bang as well, and the nature of the mysterious dark energy. This energy field causes the universe to expand at an ever-increasing rate.

Oriti’s colleague Lorenzo Sindoni therefore adds: “We will only be able to really understand the evolution of the universe when we have a theory of quantum gravity.” The AEI researchers are in good company here: Einstein and his successors, who have been searching for this for almost one hundred years.

Publication: Steffen Gielen, et al., “Cosmology from Group Field Theory Formalism for Quantum Gravity,” Phys. Rev. Lett. 111, 031301 (2013); DOI:10.1103/PhysRevLett.111.031301

PDF Copy of the Study: Cosmology from Group Field Theory Formalism for Quantum Gravity

Source: Max Planck Institute

Image: T. Thiemann (FAU Erlangen), Albert Einstein Institute, Milde Marketing Wissenschaftskommunikation, exozet effects

, , ,

Subscribe / Follow

Don't miss out. Follow the latest technology & science news via email or social media.

8 Responses to “Physicists Take a New Approach to Unify Quantum Theory and Theory of Relativity”

  1. James Moses Says:

    …..HATE to break the news but, Nassim Haramein beat them to it, and your publication, really SHOULD have made note of as much…..Nassim Haramein’s physics paper titled “Quantum Gravity and the Holographic Mass”.


    • Anastasio Says:

      “Quantum Gravity and the Holographic Mass” is ‘published’ in a predatory, pay-to-publish vanity journal over which even its chief editors have no control nor influence over its publications.

      Haramein’s manuscript is largely nonsensical numerology and explains nothing of the above. If it does, then please explain how.


  2. Wardell Says:

    The Universe is NOT expanding, not withstanding General Relativity and Friedman’s Equation.

    Gravity and Quantum Theory are united when the Law of Gravity and Quantum Rheory are correct. The correct Law is W = -vh/l + cP. This law describes the energy W as a Quaternion Energy, with -vh/l the scalar or Potential energy consisting of the velocity v, h the angular momentum and l the wavelength, l=2pi r.

    The second part of the energy is cP the momentum vector energy, aka the “Dark Energy”. The “Dark Energy” is invisible to Physicists, because physicists don’t believe in vector energy. The universe believes in vector energy and it is the dominant energy. The momentum energy, cP, adds vector energy to the scalar energy and adds the Quantum aspect, the vector, the Fermions.

    The correct Quantum Theory is W = -vh/l + cP, the same equation, uniting Gravity and Quantum Theory.

    The difference is in the “particle” vector.
    In Gravity, the particle is mass m, with v=(GM/r)^.5 .

    In Quantum the particle is charge electron e, with v= AlphaZc, where alpha is the Fine Structure Constant and Z is the Atomic Number and c is the speed of light.

    In Quantum the particle is photon Q, with v=c.

    Thus Gravity and Quantum are United. The essence of Quantum Theory is the vector energy cP. The vector is the Fermion and it is the fermions that distinguish Quantum from “Gravity Relativity, the Boson scalars.

    Quaternions W = -vh/l + cP is the sum of Bosons and Fermions, and this is the true Uniion of Gravity and Quantum Theory.

    The Energy W is bounded and thus not expanding!
    The Derivative is zero at v=c,
    and the Max W = -ch/l + cP = mc2[-1,1P].

    XW = [d/dr, DEL][-vh/l, cP] = [vp/r -cDEL.P, -cp/r 1P + vp/r 1R + cDELxP]
    XW = cp/r[v/c -cos(P), -1P + v/c 1R + sin(P)1RxP]

    At 0=XW, Mathematics and Geometry requires cDELxP=0 or sin(P)=0 and cos(P)=1

    0 = cp/r[v/c -1, -1R + v/c 1R] thus v/c=1 or v=c for Equilbrium or Invariant.

    Thus the Universe is not expanding, the redshift v/c is 1/n the inverfse refraction coefficient.

    The Big Bang, Black holes and the expansion of the Universe are Problems inPhusics, e.g. “Dark Energy, Dark matter, singlarities,etc. The new approach to the old problems is still the old problem.

    Quaternion Physics is Natures Way, without the problems.


  3. Madanagopal.V.C Says:

    Wardell cannot theorise that Universe is not expanding without knowing actual observation. Secondly he cannot conclude that energy is a vector quantity since natural energy cannot be constricted to to be propogated in a fixed line like laser except under some artificial conditions. Energy is always a scalar quantity. Annotating this article of space particles which are like vacuum space atomicity, we can come to certain conclusions. When galaxies are thrown apart by the mighty Dark Matter at a fantastic speed comparable to the velocity of light the conservation of the spent energy states that this spent energy should reside in some form in the new space created by expansion and that can be through energy particles or vacuum atoms in cosmos. Thus in the entire Universe empty space is not devoid of any energy in the absence of any matter but really it is warehouse of spent energy of galactic expansion. So you call it as Dark Energy and you should know that this Dark Energy is 72%, Dark matter is 24%, leaving just 4% for the visible universe with billions of galaxies and black holes. Thus materealisation of energy has taken place only to the extent of 4% and the force is coming from Dark Matter to produce Dark Energy continuously by creating more and more of the vacuum energy called Dark Energy.Now you can conclude that energy has got not just four forms but five forms in fact. They are Gravitational, Electromagnetic, Electroweak, Color forces or nuclear forces plus another form viz., invisible energy of the vacuum.Thank You.


  4. Deryl McCarty Says:

    This bubble theory could explain a few phenomena.

    1. If at the universe level (macro level) the bubbles are uniform, they may not be uniform at the galactic level (aka micro level), which in turn would allow us to posit that C is not equal to C where the bubbles are more concentrate (or the Planck constant is not equal to the Plank Constant at those locations.
    2. That the bubbles composed of dark energy contained by cell “walls” of dark matter are pervious to anything visible object moving at V<C but at V approaching C the amount of energy it takes to breach a cell wall becomes infinitely greater hence it is a "resistance" that limits visible objects to a V always equal to or less than C (the local version of C).
    3. That at some point when we discover how to "see" these cells and both dark matter and energy (we'd have to rename them, since they would not be dark any more)we may well be able to "map" cell wall intersections and pilot along the intersections thereby avoiding having to "breach" a cell and avoiding cell wall "resistance" and not be thereby limited to piloting at V C in fact much much higher than C, but that everything, especially visible matter and energy, behind the initial cell-building shock wave would face the cell resistance and hence “revert” to type meaning that V is limited to C, but that with the huge concentration of cells (or the reverse) that the local (at that point universal) definition of C is much higher that today and decreasing as the universe expands.

    I am definitely not a physicist nor mathematician (as is patently obvious), but am a Sci-Fi nut and am always looking for a way to explain how I got to Warp 1. And please, before you laugh, remember: the philosopher (aka sci-fi writer) always leads the mathematician, who leads the physicist, who leads the engineers, who leads the moralists/ethicists, who lead the Sci-fi writer to paint the picture of the effects of a technology on how boy meets girl, boy loses girl, boy gets girl.


  5. Deryl McCarty Says:

    Oops, a section got left out: Insert between the “V C” in paragraph 3 a “<" and put a period after the C. Then insert after that period:

    4. The cell idea also allows us to posit that at the big bang, the initial shock wave of "all matter and energy" would face literally ZERO resistance. So that as that shock wave formed bubbles ….


  6. Leonardo Rubino Says:

    There’s a lot of hidden “relativity” in (quantum) Bohr’s atom…


Leave a Reply