Objective of Quantum Mechanics to Predict Outcomes of Experiments?

Leading modern theoretical physicists can tell you:

• The objective of quantum mechanics is to predict outcomes of (quantum mechanical) experiments. 

You may find this a bit strange. Isn't the objective of theoretical physics to understand physical processes. In the case of quantum mechanics, that would be to understand the microscopic physics of atoms, electrons, protons, neutrons and more. But this is not possible in the case of quantum mechanics, since in the words of Richard Feynman:

• Nobody understands quantum mechanics.

So what is left is the to predict outcomes of experiments, which seems a bit like betting on a horse race. Or is the theoretical physicist simply mocking with you, to avoid further questions?

Ok, if the experiment agrees with the prediction, then you may view that as support to an idea that the theory is correct, in that specific case. But to confirm a theory by experiments requires massive experiments. It is not enough, in general, to make just one experiment and then say that the theory is correct. Maybe that experiment was very special? 

In any case this practised a lot: To confirm Einstein's General Theory of Relativity GR, it was enough with one observation of a very slight change of the apparent position of a star during the solar eclipse on May 29 in 1919 (the perihelion shift of Mercury was not a prediction). For a second confirmation, we had to wait until the LIGO gravitational wave detection at 09.51 UTC on 14 September 2015 of two ~30 solar mass black holes merging about 1.3 billion light-years from Earth. But that was also a very special case. In any case, GR is now considered to be fully confirmed by two very special/extreme (and questionable) observations. 

Similarly, the Standard Model of fundamental physics is supposed to now be fully confirmed by very special experiments at LHC completed in 2012 showing existence of the Higgs boson after a 40 year long fruitless search, as a little jump on an energy graph. 

But if the experiment does not agree with theoretical prediction, what to do? Throw the theory away because it fails on one experiment? Maybe quite reasonable if the experiment is relevant. The alternative is to modify the theory by e g some new parameter to agree with the experiment, but then the prediction aspect is missing. Of course it is also possible to modify the experiment until agreement with theory, but again without true prediction.

To fully confirm a general theory by experiments is impossible. To confirm a general theory by very special experiments, as seems to be the current standard, is not very convincing to me. 

Newton's theory of gravitation is a general theory, which is supported by a generality of  experiments/observations and contradicted by none, and can be understood from conservation principles. It can serve as the role model for all of theoretical physics.

 

If the element of understanding is missing, then theoretical science seems to reduce to fitting theory to experiment or vice versa. Is this the reason for the current crisis of fundamental physics? 

What then about GR? Again, we have a theory which is very difficult to understand. Einstein said he could not understand it, but how is it possible to formulate a theory without understanding it? Of course a modern physicists would proudly say that there are two main theories of modern physics, quantum mechanics and GR (which happen to be contradictory/incompatible), and then act as if he/she understand these theories quite well, if not in full detail, while showing no willingness to go into a discussion about specifics of the theories and referring instead to the very rich literature explaining GR written by people who really understand GR.  

It means that a modern theoretical physicist will have to struggle with general theories, which cannot be understood nor confirmed by experiments, since only very special experiments are available, if any at all.

At the same time the modern theoretical physicist must give the impression of understanding and presence of confirmation.

  

 

The Higgs: Searching for an Elephant by Microscope

Modern physics is based on two supposedly incompatible theories for the four forces of physics acting on different scales

1. gravitational force: macroscopic: relativity theory: cosmology 
2. electromagnetic, weak and strong forces: microscopic: quantum mechanics: atoms  

The incompatibility has made a unified theory impossible and has driven modern physics into absurdities such as searching for the origin of macroscopic gravitation on microscopic atomistic scales.

The 2013 Nobel Prize for the Higgs particle falls into this tradition: The idea is that mass or matter as the subject of macroscopic gravitation is generated from subatomic interactions through the Higgs particle with the Higgs field as an endless ocean in which the Universe is floating. 

Since the manifestation of mass is gravitation, it means to search for macroscopics in microscopics, that is searching for an Elephant using a microscope (quantum loop gravity and string theory) . It does not seem to me to be a constructive approach.   

A different approach is sketched in my pet theory described in Newtonian Gravitation of Matter and Antimatter exploring the possibility that 

• the basic element of the Universe is a gravitational field $\phi (x,t)$ depending on a space coordinate $x$ and time coordinate $t$
• matter and antimatter of density $\vert\rho (x,t)\vert $ is created by differentiation with respect to $x$ of the field $\phi (x,t)$ through the Laplace operator $\Delta$: $\rho =\Delta\phi$ with matter where $\Delta\phi >0$, antimatter where $\Delta\phi < 0$ and vaccum where $\Delta\phi =0$
• a gravitational force $F$ arises as the space gradient $\nabla$ of the field $\phi$: $F = \nabla\phi$.    

It is thus the gravitational field $\phi$ which 

• creates visible matter where $\Delta\phi$ is positive and singular
• creates visible antimatter where $\Delta\phi$ is negative and singular
• creates dark matter and antimatter where $\Delta\phi$ is smooth  
• separates matter and antimatter by gravitational repulsion
• concentrates matter by gravitational attraction.

What about that? Hint: The Hen and the Egg of (Dark) Matter. This is something completely different from the Higgs as an "explanation" of the origin of mass.

  

Slinky as Alternative to Higgs Mechanism of Giving Mass to a Body

The popular description of Higgs' mechanism supplying mass to a body awarded the 2013 Noble Prize in Physics, goes as follows:  Imagine a celebrity (e.g. Brad Pitt) moving through a crowd of people drawing attention from inescapable interaction with the crowd, which can be imagined to generate some kind of resistance to the motion of the celebrity connecting to the amount of fame, or mass, of the star:

A more technical description from Wikipedia goes as follows:

• Particles (celebrities) gain mass by interacting with the Higgs field (the crowd) that permeates all space. More precisely, the Higgs mechanism endows gauge bosons in a gauge theory with mass through absorption of Nambu–Goldstone bosons arising in spontaneous symmetry breaking.

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The idea is evidently that a body acquires mass from interaction with some form of background field or crowd.Is this credible? Maybe. Maybe not. 

In any case, here is a reprint of a different mechanism that I reflected on some time ago as a possible resolution of Zeno's paradox of the impossibility of motion with a Slinky as mental image:

The basic idea is that the slinky moves so to speak by itself and not by interacting with a background field. The kinetic energy of the slinky = 1/2 x mass x velocity^2 equals the energy invested to compress or extend the slinky before letting it go. Mass can then be defined in terms of velocity and invested energy stored as kinetic energy through the motion. Mass is then something carried by the slinky through motion related to the stored energy, which can be released by letting the slinky run into a wall. Is this credible? Maybe. Maybe not.  Will Slinky get a Nobel Prize? Maybe not. 

The motion of a slinky suggests a resolution of Zeno’s Arrow Paradox as a combination of compression-release and switch of stability, where the the slinky appears as a soliton wave, which itself generates the medium through which it propagates.

Zeno of Elea (490-430 BC), member of the pre-Socratic Eliatic School founded by Parmenides, questioned the concept of change and motion in his famous arrow paradox: How can it be that an arrow is moving, when at each time instant it is still?

In Resolution of Zeno’s Paradox of Particle Motion I argued that the paradox still after 2.500 years lacks a convincing resolution, and suggested a resolution based on wave motion.

A fundamental question of wave propagation is the nature of the medium through which the wave propagates: Is it material as in the case of sound waves in air, or is it immaterial as in the case of light waves in vacuum? If the flying arrow is a wave, which is the medium through which it propagates? It is not enough to say that it is air, because an arrow can fly also in vacuum.

We are led to the following basic question: can a wave itself act as the medium through which it propagates?

It turns out that a slinky can serve as an answer! To see this take a look at this movie . We see that the motion of a slinky can be described as follows:

• oscillation between two forms of energy: elastic energy and kinetic energy compression stores elastic energy 
• elastic energy is transformed into kinetic energy when the slinky expands
• there is a critical moment with the slinky fully compressed in which the downward forward motion of the top ring is reflected in upward forward (and not upward backward motion which would lead to motion on the spot) 
• the slinky forms itself the medium through which it as a wave propagates
• the slinky acts like a soliton wave.

We understand that the slinky offers a model for resolution Zeno’s paradox as a wave which itself generates the medium through which it propagates.

What is Mass?

You can take this model one step further, and view the work required to compress the slinky from an uncompressed rest state, as an investment into kinetic energy of motion, just as a body can be accellerated from rest by the action of a force and gain kinetic energy.

This would mean that the slinky has inertial mass and that it can move with different velocities depending on the amount of work invested in the initial compression. We may compare with the propagation of massless electromagnetic waves with given fixed speed of light. This connects to the question Does the Earth Rotate? suggesting to define mass as inertial mass M in terms of kinetic energy K and velocity V from the formula K = 1/2 x M x V x V.

PS1 The difference between Higgs and Slinky is a bit like the difference between environment and genetics for living body, with Higgs only exterior environment and Slinky only interior genetics.

PS2 There is a connection to Wittengenstein's ladder which the user successively pulls up behind as the  climbing advances.

PS3 The Higgs mechanism is described in the above picture to "slow down" the motion of an electron as an effect of some kind of viscosity. This seems strange since electrons are not "slowed down" by the mere fact that they have mass. Acceleration is "slowed down" by mass but not velocity.