A preview of the slides, arguing how the Planck scales lead to particle physics and gravity:
• An appetizer: a final theory that fits on
a Tshirt• The flow of the
story• Enjoying physics
• Predictions of the strand model• Status of the predictions• Support•
Discussion and outlook•
Read online
What determines colours? What is motion?
All colours in nature derive from the fine structure
constant 1/137.035 999 14(3). This is the most famous unexplained number in
nature. What determines its value?
All motion in nature is
described either by Einstein's general relativity or by quantum theory with
the standard model of particle physics, two theories that contradict each
other. How can they be unified in a final theory?
If you enjoy exploring
ideas and checking them against the real world, you might like this book.
It first explains why the past proposals for a final, unified theory of
physics – the socalled 'theory of everything' – have failed.
Then the text presents a better proposal, called the strand model.
This model agrees with all experimental data known so far and makes clear,
falsifiable predictions. They are being tested in experiments around the
world. The strand model
– is based on one simple fundamental
principle – and thus is lean and beautiful,
– predicts
general relativity and a specific cosmology – and allows no alternative
or extension,
– predicts quantum theory and quantum field theory
– and allows no alternative or extension,
– predicts the
standard model of particle physics – and allows no alternative or
extension,
– and proposes how to solve the open issues of the
standard model, gravitation and cosmology, including the explanation of all
fundamental constants.
All these results follow from a single fundamental
principle about motion. Prepare yourself for a roller coaster ride trough modern
physics, and for the excitement of solving one of the oldest physics puzzles
known. This is an adventure that leads beyond space and time – right to
the limits of human thought. For example, the adventure shows that the term
'theory of everything' is wrong, whereas 'final theory' is correct.
Fast reading: for a quick overview of the book, read the summary of each chapter, or better, read the slides at the top of this page.
The colour pdf file with embedded animations, shown at the end of this page, is free. If you want a paper version delivered to your address, or a Kindle edition, click the links at the top left of this page.
An appetizer: a final theory that fits on a Tshirt
The text presents an approach to the final, unified theory of physics with a simple basis but intriguing implications. The model is based on featureless strands that form space, particles and horizons; the model sums up textbook physics in a single fundamental principle: events and Planck units are crossing switches of strands.
Surprisingly, this fundamental principle, which works in three dimensions only, allows deducing Dirac's equation (from the belt trick), the principles of thermodynamics and Einstein's field equations (from the thermodynamics of strand crossing switches). As a result, quantum theory and general relativity are found to be lowenergy approximations of processes at the Planck scale. In particular, strands explain the entropy of black holes (including the numerical factor).
As a further surprise, the fundamental principle predicts three fermion generations, the Higgs boson, and the lack of any unknown elementary particles. In the strand model, all particles are defects in the vacuum. In particular, particles are unknotted tangles. Each particle is a different (rational) tangle: leptons are made of three strands, quarks of two strands, and bosons of one, two or three strands. (More precisely, every massive particle is a specific infinite series of tangles.) The quark model and the construction of all mesons and baryons are shown to follow from strands. In other words, tangles of strands and their crossing switches explain all known elementary particles, all their quantum numbers, and the lack of any other elementary particles. The strand model might be the first unified model predicting the elementary particle spectrum.
As a final surprise, the fundamental principle yields the three gauge groups and the Lagrangians of quantum electrodynamics, of the strong and of the weak interaction, including maximal parity violation and SU(2) breaking. The three Lagrangians appear as a natural consequence of the three Reidemeister moves of knot theory. The strand model does not permit any further interaction, gauge group or symmetry group. The strand model might even be the first unified model predicting the three gauge interactions – and the lack of other ones. The strand model thus suggests that the standard model is the final description of particle physics.
In QED, the strand model proposes a simple understanding of Feynman diagrams and of Schwinger's formula for the anomalous magnetic moment of the electron and the muon; the model even sheds new light on the possibility of nonperturbative calculations.
A natural method for the calculation of coupling constants, particle masses and mixing angles appears. So far, mass sequences, several mass ratios, the weak mixing angle and the order of magnitude of coupling constants are predicted correctly. Again, the strand model might be the first unified model allowing such calculations. More calculations are under way; the book is regularly updated.
The strand model also fulfils a famous wish about the final theory of motion: it fits on a Tshirt. This wish is less frivolous than it sounds, because it asks for a clear and simple fundamental principle. You can buy the Tshirt here. You can find its description here.
The flow of the story
The text starts by listing all open issues in fundamental physics since the year 2000. The list contains the unexplained constants of nature  such as coupling constants, elementary particle masses and mixing angles  the origin of quantum numbers, of spatial dimensions, of wave functions, of the metric, of least action, plus a number of cosmological issues, including the nature of dark matter and the origin of the cosmological constant. The text summarizes various unsuccessful approaches to explain the origin of these unexplained observations.
To find a better approach for a final theory, modern physics is first simplified as much as possible. The results of this simplification are used to deduce the full list of requirements that any final theory must fulfil. These requirements also explain why the previous approaches failed. In particular, it is shown in detail that the main requirement for a final theory is the extension of nature's constituents.
Then the strand model is introduced and discussed; it is shown, step by step, that it satisfies each requirement, that it solves all open issues, and that it agrees with all experimental data. In particular, the strand model is based on Planck units, uses neither continuity nor discreteness as fundamental concepts, and does not assume that points or sets exist at Planck scale. The model has no free parameters, is unique and unmodifiable, and works in three spatial dimensions only. However, dimensionality is not a parameter, but a result of the model: other numbers of dimensions are impossible.
As required from any final theory, the strand model makes definite experimental predictions, given below. The predictions are quite unpopular and contradict those of other unification proposals, but so far, none is falsified by experiment.
Enjoying physics
The search for a unified description of all motion in nature is a fascinating and beautiful adventure. Numerous wonders of nature are encountered, including unexpected and captivating views on determinism, on induction, on the axiomatization of physics and on the mass gap in gauge theories. The search is indeed fascinating, but is not more than that: unification has no application in technology or in business and confers no power whatsoever. Anybody who assigns to unification more importance than to a riddle is already on the wrong track. Searching for unification is like looking for a beautiful flower in a large field during a walk through the countryside. The search is a pure pastime.
In the strand model, the universe is made of one strand crisscrossing and woven into the sky. It is fun to find out how playing with strands at Planck scale reproduces quantum theory, general relativity and the standard model, including its gauge groups and its particle spectrum. By the way, the strand model is not related to loop quantum gravity nor to string theory. And the strand model should not be called the 'spaghetti model': spaghetti have ends, strands don't.
The text entertains and surprises on every page, while being written as simply as possible. It presupposes knowledge about the concepts of electric charge, particle, Lagrangian, wave function, gauge symmetry and space curvature. Not more. If you need to learn about these topics, read the previous five volumes of the Motion Mountain series; they provide an introduction to these concepts – and to established physics in general – with as little math and as much pleasure as possible.
Enjoy the reading!
Predictions of the strand model
A final theory must make experimental predictions. All predictions of the strand model (except one that was corrected later) were made in 2008/2009, i.e., before any experiment at the LHC in Geneva, or on neutrinos, on forbidden muon decays, on electric dipole moments, on QCD, on dark matter searches, or in astrophysics. The predictions that are typeset in bold characters (and a few others) are unique to the strand model:

These predictions contain risks: additional tangles that were unaccounted for or overlooked until now could arise, and with them yet unknown particles or dark matter states.
Status of the predictions
Experiments
So far, not a single
experimental result contradicts the predictions of the strand model
deduced from the fundamental principle. The most recent results from the LHC
at CERN have confirmed the standard model of particle physics up to an energy
of around 2 TeV. They found no supersymmetry, no higher dimensions, nor
anything unexpected. Neither did the many recent dark matter experiments
around the world find any deviations. Also every experiment that tested
gravity, including the detection by LIGO of gravitational waves, fully
confirmed general relativity, excluded any deviation,
and thus confirmed the strand model.
Of course, upcoming experiments still have many possibilities to falsify the strand model: a single observation that disagrees is sufficient, because all predictions follow from a single principle. So far, no such falsifying observation is known, and the Tshirt with the fundamental principle describes correctly all known observations.
Calculations
To
verify the strand model, there is only one possibility: to calculate
the constants of the standard model. This project is under way. The first
crude approximation of 2013 yielded a fine structure constant value of 1/191,
instead of the measured value 1/137.036(1). The result, possibly the first
known estimate from first principles, is not too disappointing.
In the summer of 2014, a reader suggested that the original tangles proposed for the W and Z might be wrong, out of aesthetic and consistency reasons. In 2016, his criticism led to new calculations of the Z/Higgs and W/Higgs mass ratios. They are near the observed ones. In addition, the updated calculations of the fine structure constant are very promising. The proposed tangles for the leptons probably need improvement. Also the origin of particle spin and particle mass needs to be clarified in more detail. The strand model thus remains a work in progress. The remaining effort for these topics is estimated to be about two fulltime years.
Other theoretical work
In general
relativity and quantum gravity, and after the strand model was proposed,
completely independent theoretical investigations appear to confirm several
aspects of the strand model. Examples are Carlip's fluctuating lines in
space, Botta Cantcheff's fluctuating strings in space, Susskind's speculation
of black holes as single woundup strings, Verlinde's emergent gravity,
Kempf's model with both continuity and discreteness, and recent cosmological
models with a timedependent cosmological constant.
The fundamental principle can be seen as a specific and falsifiable realization of `it from bit' and `it from qubit'. Also entanglement has a natural explanation in terms of strands. These research fads arose after the strand model.
In particle physics, the strand model confirms unpopular ideas that are scattered through the research literature. Examples are Weinberg's suggestion that the standard model plus general relativity is all there is, and the 1980 paper by BatteyPratt and Racey deducing the Dirac equation from a tethered ball. The various calculations showing that the Higgs boson has exactly the mass value that is required to make the standard model valid up to Planck energy can also be listed here.
Detailed status on the Higgs – with the lessons from a
past mistake
In 2012, two experiments at the LHC in Geneva
have observed a neutral boson with a mass of 125 GeV. It has spin 0, positive
parity and is elementary.
Assuming that the observed boson is indeed the Higgs boson  and there is no reason to question this  the 'dirty trick' candidate tangle shown on the left of Figure 91 seems to apply to it. The candidate tangle shown in that figure is part of the text since it was published in 2009 and was always mentioned as possible Higgs boson tangle. In 2009, it was argued that the candidate tangle could not be correct and thus the lack of a Higgs was predicted. The discovery of the Higgs boson in 2012 required a check of those arguments. The check showed that the arguments were wrong. Correcting the arguments, a more detailed and improved prediction is possible:
– Assuming that the Higgs tangle on the lefthand side of Figure 91
is correct, then the tangle implies a Higgs boson with vanishing charge,
positive parity and being elementary.
– If only one standardmodel
Higgs boson exists and if the tangle of Figure 91 is correct, the strand model
agrees with all data.
– The tangle, together with the new W and Z
tangles, suggests a crude mass approximation for the Higgs boson of 121 to 128
GeV.
– If several Higgs bosons exist or if the tangle of Figure 91
does not apply, the strand model is in trouble.
– The strand model
continues to predict the lack of supersymmetry.
– In the case that
effects or particles or interactions beyond the standard model are observed,
the strand model is in trouble.
A longer evaluation is found in the text. After correction of the mistaken prediction, there is no contradiction between experiment and the strand model. In tabloid terms, the strand model continues to predict the socalled 'highenergy desert', also called the 'nightmare scenario': up to almost the Planck scale, highenergy physics is completely described by the standard model of particle physics  and by nothing else.
Support
You can support the project by solving one or several challenges from list C on the prize challenge page – and even earn prizes doing so.
You can also sponsor the project with a donation to our tiny charitable nonprofit association, the Motion Mountain Physikverein. The use of your donation is controlled by the German tax authority. Your donation will be used to complete the research project. This will take another two years of effort.
Every donor is acknowledged by email and, if desired, in the book, on the site, or even more.
Discussion and outlook
The model is work in progress. It is not ripe for publication yet. The above slides explain why. Besides, any unified theory of physics should never be taken too seriously.
Feel free to contribute issues, criticisms or suggestions to the wiki at sites.google.com/site/motionmountainsuggestions. You can also email me at christoph@motionmountain.net. Past discussions about the strand model can be found here. Some background is given on my old blog on fundamental research and on my old blog on teaching.
A preview of the text:
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