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An appetizer: a simple final and unified theory
Physics on a Tshirt
Enjoying physics
The flow of the story
Table of contents
Open issues in fundamental physics
Requirements for a final theory
Predictions of the strand model
Status of the predictions
Support
Discussion
wiki
What determines colours? What is motion?
All colours in nature derive from the fine structure
constant 1/137.035 999 1(1). 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 volume. 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 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
promises to solve the open issues of the standard model, gravitation and
cosmology, including the explanation of all fundamental constants.
All these
results follow from the fundamental principle. 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.
The colour pdf file with embedded animations, shown just below, 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 simple final and unified theory
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, in the same approximation, 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.
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.
As a final surprise, the fundamental principle predicts three fermion generations, the Higgs boson, and the lack of any unknown elementary particles. The strand model thus predicts that the standard model is the final description of particle physics. 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.
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 volume is regularly updated.
Physics on a Tshirt
The strand model thus 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. To support the project, you can buy the Tshirt here.
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.
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. If desired, the strand model can also be called 'spaghetti model'. But the model is not related to loop quantum gravity nor to string theory.
The text entertains and surprises on every page, while being written as simply as possible. It only presupposes knowledge about the concepts of electric charge, particle, Lagrangian, wave function, gauge symmetry and space curvature. 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!
The flow of the story
The text starts by listing all open issues in fundamental physics since the year 2000. They are given in the table of the millennium issues below. The text then presents various unsuccessful approaches to solve these issues. To find a better approach, 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, also given below. The predictions are quite unpopular and contradict those of other unification proposals, but so far, none is falsified by experiment.
Download volume VI (34 MB)  THE STRAND MODEL – A SPECULATION ON UNIFICATION  
1  From millennium physics to unification – the open issues of fundamental physics  17 
2  Physics in limit statements – simplifying physics as much as possible  26 
3  General relativity versus quantum theory – their contradictions and our quest  55 
4  Does matter differ from vacuum? Not always – first requirements for any final theory  63 
5  What is the difference between the universe and nothing? – More requirements for any final theory  88 
6  The shape of points – extension in nature – an essential requirement for any final theory  113 
7  The basis of the strand model – and the full list of requirements for any final theory  142 
8  Quantum theory of matter deduced from strands  167 
9  The three gauge interactions deduced from strands  216 
10  General relativity deduced from strands  270 
11  The particle spectrum deduced from strands – and the lack of new physics  302 
12  Particle properties deduced from strands – and all predictions of the strand model  343 
13  The top of the mountain – the beauty and some new sights  384 
Open issues in fundamental physics
This is the full list of questions that are unsolved in fundamental physics since the year 2000, the socalled millennium list of open issues. (In fact, they are unsolved for an even longer period of time.) A correct description of nature must solve each of these questions. Only such a description qualifies as a unified and final theory.
OBSERVABLE  PROPERTY UNEXPLAINED SINCE AT LEAST THE YEAR 2000 
α  1/137.0359991(1), the low energy value of the electromagnetic coupling constant 
α_{w} (or θ_{w})  the low energy value of the weak coupling constant (or of the weak mixing angle) 
α_{s}, θ_{CP}  the value of the strong coupling constant at one specific energy value and the strong CP violation constant 
m_{q}  the values of the 6 quark masses 
m_{l}  the values of 6 lepton masses 
m_{W}  the value of the mass of the W vector boson 
m_{H}  the value of the mass of the scalar Higgs boson 
θ_{12}, θ_{13}, θ_{23}  the value of the three quark mixing angles 
δ  the value of the CP violating phase for quarks 
θ'_{12}, θ'_{13}, θ'_{23}  the value of the three neutrino mixing angles 
δ', α_{1}, α_{2}  the value of the three CP violating phases for neutrinos 
3 x 4  the number of fermion generations and of particles in each generation 
J, P, C, etc.  the origin of all quantum numbers of each fermion and each boson 
c, ħ, k  the origin of the invariant Planck units of quantum field theory 
3+1  the number of dimensions of physical space and time 
SO(3,1)  the origin of Lorentz and Poincaré symmetry (i.e., of spin, position, energy, momentum) 
S(n)  the origin of particle identity, i.e., of permutation symmetry 
U(1)  the origin of the electromagnetic gauge group (i.e., of the quantization of electric charge, as well as the vanishing of magnetic charge) 
SU(2)  the origin of weak interaction gauge group and its breaking 
SU(3)  the origin of strong interaction gauge group 
Ren. group  the origin of renormalization properties 
δW = 0  the origin of wave functions and of the least action principle in quantum theory 
W = ∫ L_{SM} dt  the origin of the Lagrangian of the standard model of particle physics 
0  the observed flatness, i.e., vanishing curvature, of the universe 
1.2 ⋅ 10^{26} m  the distance of the horizon, i.e., the ‘size’ of the universe 
ρ_{de} = Λc^{4}/(8πG) ≈ 0.5 nJ/m^{3}  the value and nature of the observed vacuum energy density, also called 'dark energy' or 'cosmological constant' 
(5 ± 4) x 10^{79}  the number of baryons in the universe, i.e., the average visible matter density in the universe 
f_{0}(1, ..., c. 10^{90})  the initial conditions for c. 10^{90} particle fields in the universe (if or as long as they make sense), including the homogeneity and isotropy of matter distribution, and the density fluctuations at the origin of galaxies 
ρ_{dm}  the density and nature of dark matter 
c, G  the origin of the invariant Planck units of general relativity 
δ ∫ L_{GR} dt  the origin of curvature, of the least action principle and of the Lagrangian of general relativity 
R × S^{3}  the observed topology of the universe 
As shown in the text, the strand model proposes an answer to each of these open issues. Each answer follows unambiguously from the single, fundamental principle that strand crossing switches define the Planck units.
Requirements for a final theory
Any final theory must fulfil certain requirements. The first half of the text shows how each requirement follows from the expressions for the Compton wavelength and for the Schwarzschild radius, i.e., when quantum theory and general relativity are combined. The full list of requirements that arise is given in the text. That full list can be summarized in the following way:

These two requirements, and all those of the full list, appear only when quantum physics and general relativity are combined. No requirement follows from one theory alone. This makes the search for the final theory a special challenge; in a sense, the requirements for the final theory contradict both quantum physics and general relativity. The final theory therefore contradicts each part of 20th century physics.
The second half of the text shows, step by step, that the strand model fulfils the full list of requirements. In fact, the strand model is the only present candidate for a final theory that fulfils them. In addition, the strand model makes several predictions that can be tested against observation.
Predictions of the strand model
All predictions (except the corrected one) of the strand model 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:

Risk of these predictions: 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, 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 lead to new tangles and thus to new Z/Higgs and the W/Higgs mass ratios. They are near the observed ones. The updated calculation of the fine structure constant still needs to be performed. On the other hand, the proposed tangles for the leptons most probably need improvement, and the origin of particle spin and particle mass needs to be clarified. The strand model thus remains a work in progress. The remaining effort for these topics is estimated to be 2 manyears.
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 Botta Cantcheff's fluctuating
strings in space, Susskind's speculations of black holes as single woundup
strings, Carlip's fluctuating lines in space, Verlinde's emergent gravity,
Kempf's model with both continuity and discreteness, and recent cosmological
models with a timedependent cosmological constant.
In particle physics, the strand model turned out to confirm 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 85 on page 291 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
on page 318 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 charitable nonprofit association. 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 one or two personyears of effort.
Every donor is acknowledged by email and, if desired, in the book, on the site, or even more.
Discussion wiki
Feel free to contribute issues, criticisms or suggestions to the wiki at https://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 blog on fundamental research and also on my blog on teaching.
rs* * *