I have read many reports that indicate small physical measurements. They measure a few electrons or a few photons with people that are not trained in chi.
This is not enough for the skeptic scientists that need "extraordinary evidence for extraordinary claims". These need to be convinced before the scientific community changes.
For other scientists we need some clear models of how we can understand this phenomenon.
For science we need:
1) a theory
2) a method of measurement
So here is my current theory:
Looking at the current physical model of science we can see holes in some aspects of it. One hole is that quantum-mechanics describes everything in statistical properties, but gives no clear solution to what is really happening.
Let me rephrase it: if an electron circles a nucleus, we have no idea where it is exactly. There are photographs of atoms, but they show a sphere and not a bunch of electrons that circle around.
Quantum-mechanics can explain the average situation, and can predict how often certain situations occur, but does not explain the total behavior of the electron.
So there is a gap there in the behavior of the electron.
So let me assume that this chi is able to influence the electron, without affecting any physical laws. We can see that this is certainly possible if chi would affect the timing of certain electron reactions. And it may start reactions only if the energy balance is restored afterwards. It could cause an atom to lose an electron, but it will get the electron back later.
If chi can only affect only these little things, it is already able to control the chemical reactions in the body. So there is a possible place for chi.
But let us look at the biological body instead: There we see that some important molecules are in a super-position state. That means that biology does something we do almost never see in normal chemistry: a molecule is in two states at the same time. see /r/QuantumBiology for that.
So if living bodies prefer chemicals that are in a superstate position, this is probably related to chi. So what is happening when a molecule or atom is in a superposition?
We can look again at the electron around the atom: the electron is in a band around the atom forming a sphere. We model it as a small particle that rotates in a circle, but we observe a sphere that is fully round. That is because the electron is in a superposition state also. It at all the places at the same time.
It does not seem to follow exactly the orbits that we predict with quantum-physics, but mostly show perfect spheres. This might be an interesting subject to go in to later.
So it seems that the superposition state is a state in which the electron or atom or molecule is at more places at once, but there is no law of physics that describes which place it has to be at a certain time. If chi can affect this place at a certain time, it is able to guide these molecules. And because these molecules are in many important biological processes, we can assume that chi is be able to affect these processes.
Where else in physics do we see that the timing of quantum-physical processes is important?
Currently it seems that the principle of the laser has a similar idea. There are many excited atoms in a chamber, surrounded by mirrors. These excited atoms might release a photon at any moment. But as one photon is released, all other atoms do the same thing. The mirrors cause the photons to go repeatingly through the excited atoms, so the chance is higher that they all join up.
This causes lasers to emit light mostly in one frequency and phase.
If chi is able to affect the timing of such quantum-processes, it can become very strong if the chi can cause all these quantum-processes are synchronized.
This explains why people that are trained in chi can sometimes do marvelous things.
So my conclusion is: chi is likely able to affect the timing of quantum-processes.
Then how can we measure it?
If chi is able to influence the timing of quantum-processes we can use objects that are in a superposition state and see how these behave near people.
We could put electrons in some kind of excited state on one plate, and put another plate underneath to measure the electrons that have come across the barrier.
The strange thing is, people already did that.
If you look at kirlian photography, http://kirlianresearch.com/[2] you can exactly see such a device.
Sadly they originally claimed it was the aura that they photographed, but they do not. There seems to be a correlation with the chi that influence the excited electrons, but also other factors may influence these electrons.
As far I understand it does give some kind of measurement of the chi coming from a person or object. The website gives in interesting list of papers:
http://kirlianresearch.com/gdv_publications.html
An other means might be using water molecules and expose them to chi. The water seems to freeze in different ways, depending on the exposure to chi. Behind the freezing process there is likely a quantum-process that guides the molecules to certain forms. If chi causes these freezing molecules to be more synchronized, we might expect nicer ice-crystals to be formed.
This again seems related to the work of emoto:
http://www.masaru-emoto.net/english/water-crystal.html
Sadly he claims that the emotions are resposible for the forming of crystals, but it is actually the chi (that might be related to these emotions).
So what about nuclear reactions?
Also here is a difference between living persons and dead persons. In science we are using the C13 method to determine how long ago a person or plant has deceased.
http://en.wikipedia.org/wiki/Carbon-13
But determining the C13 content of a person, or plant it might kill them, so I hope we find a different method to look into these things.
Chi in action by trained person
(external links)
http://paradigm.zxq.net/yanxin/
It lists scientific research of a master in Qi-Gong doing all kinds of experiments in the laboratory.
Some of them are about nuclear decay.
A trained person "the iceman" has been researched by western scientists
extensively, and he is capable of keeping is body warm in extreme cold circumstances.
http://www.innerfire.nl/iceman