Norman
Allan


"quantum"


the
skinny, so far


wikisays:
"Broadly speaking, quantum mechanics incorporates four classes of
phenomena for which classical physics cannot account:
~ quantization of certain
physical properties 

~ light (and all other stuff) is pixelated; made up of "quanta", photons (in the case of light), and their energy is (integer/whole number) multiples of a constant value, Planck's constant.

It starts with Max Planck
and a consideration of Matter, when it has any thermal
energy above "absolute zero" (0 degrees Kelvin), emits electromagnetic
radiation. (The famous "cosmic background
microwave radiation" corresponds to a temperature
of 2.7K) A dark body starts to glow with visible light (dully
red) at around 800K. At 1000K it glows red. At 6000K it glows white.


Einstein and the "photoelectric effect" If you shine light at a surface
it can, in certain circumstances/conditions cause electrons ("photoelectrons")
to be emitted from that surface. So, Einstein
is saying that electromagnetic waves exist as discrete wavepackets,
"light quantum", Lichtquant. Planck has said that there
is a minimum energy to these "bundles" or "energy elements".:
: 
"Quanta": wikisays:
In 1900, the German physicist Max Planck was studying blackbody radiation
and suggested that the energy carried by electromagnetic waves could
only be released in "packets" of energy. In his 1901 article
in Annalen der Physik he called these packets "energy elements".
The word quanta (singular quantum) was used before 1900 to mean particles
or amounts of different quantities, including electricity.
The seminal "article"
was titled, "On a Heuristic Viewpoint Concerning the Production
and Transformation of Light" "Photon": wikisays: the name photon derives from the Greek word for light. Arthur Compton used photon in 1928, referring to Gilbert N. Lewis usage. The same name was used earlier, by the American physicist and psychologist Leonard T. Troland, who coined the word in 1916... 

There is a context this work on quantum is being to developed to explain: In the same year. 1905, that Einstein published hi work on the photoelectric effect, giving us quanta of light, photons, he also puiblished his special relativity giving us meanwhile physicists are throwing stuff at stuff and watching how stuff comes apart. and from this building a picture of the world... like Rutherford throwing alphaparticles at stuff and only a small percentage is scatterd: from this it is deduce that the nucleus is only a small tiny spot in the centre of an atom 
There is a context to this : it's when Rutherford took apart atoms ~ there are/were "radioactive radiation"


Niels Bohrs and the spectral lines of Hydrogen. It was known that "the
light radiated by the hydrogen atom"(1)
produced a series of spectral lines... 
Electron
transitions and their resulting wavelengths 

(Niels Bohr went on to develop the model of the atom much as we now know it.) 


That's the easy part: light (and stuff) is pixelated; made up of "quanta", photons (in the case of light), and their energy reflects the frequency/wavelength multiplied by a constant term for the energy involved, Planck's constant. (does this relate to c? a sort of reciprical?) The next bits are more complicated and come out of the discover of radioactivity at the end of the 19th century, the discovery of "cathode rays", electrons, and discoveries and theories about the composition of atoms. Or maybe not.. 

1924:
de Broglie (pronouced "de
Broy") conjectured that all matter should have wavelike
attributes... matter waves... and calcuated... note: the bigger the mass, the smaller the wavelength! Which is one of the reasons large things don't apparently show "quantum behaviour". Prof. Deybe asked Schrodinger to explain this and (1925) Schrodinger went on to explain how probability waves move, calculating "probability amplitudes" psi according to wiki: following up on de Broglie's ideas, physicist Peter Debye made an off hand comment that if particles behaved as waves, they should satisfy some sort of wave equation. Inspired by Debye's remark, Schrödinger decided to find a wave equation for the electron. and/or using the relativistic energy momentum relation 
Schrödinger equation ... describes how the quantum state of a quantum system changes with time. ... The concept of a wavefunction is a fundamental postulate of quantum mechanics. ... “derivations” of the Schrödinger equation demonstrate [the] mathematical plausibility for describing waveparticle duality ... (wiki)


I've
thrown in lots of equations into this presentation. Do I understand them.
Hell no. But, mathematics is of the essense of quantum mechanics... so ... The site, "Hyperphysics", say of Schrodinger's equation... 

(2) "One of the reasons for the almost immediate and universal acceptance of Schrodinger's equation was that after a decade or more of fumbling around in the dark, physicists were once more able to calculate using standard mathematical techniques. Instead of havimng to follow Bohr's mysterious rules, the energy levels of hydrogen appeared naturally as the allowed frequencies of a wave problem in three dimensions. Indeed, what was astonishing was the remarkable accuracy of these predictions. (2)


with reference to Schrodinger's cat  Hey and Walter's say: von Newman said (way back then) that consciousness of the observer must play a big roll in the collapse of the wave function. They also say that Wojciech Zurek said that "Bombardment by solar photons is enough to constitute a measurement and to distroy any quantum coherence."  
Probability and Uncertainty The discover of "radioactivity" in the late 19th century, with the observation of, and concept of, "half lives"... of unpredictability, had introduced probability as a theme... but not yet as a fundemental aspect of all and every thing. Note, though: the Uncertainty Principle is different! It says there is a (fundemental, intrinsic) limit to what we can know : know about certain paired qualities such as location and/or momentum). (even the pixels are smudged? when you try to see them... (oh; and it's from radioactivity (alpha, beta, and gamma radiation) that Bohr took apart and put together the atom, I think) 

Wikisays:
"In classical physics, the derivatives of action are conjugate variables
to the quantity with respect to which one is differentiating. In quantum
mechanics, these same pairs of variables are related by the Heisenberg
uncertainty principle.
~The energy of a particle
at a certain event is the negative of the derivative of the action along
a trajectory of that particle ending at that event with respect to the
time of the event. 

I am inclined to believe that in the famous double slit experiment, with electrons, where, if the wavecicles are not "observed", they go through both slits in a probabilistic "wavelike" manner and generate an interference pattern, but if they are observed they can be seen to go through one slit or the other and the probability wave function collapses, and one sees two discrete bands... that this might be a matter of whether or not something discrete had occured, rather then that something discrete had been observed to occur... so if...  
A Thought Experiment: Probability Wave Collapse In the double slit experiment, if one beamed electrons through the slits at a screen, shining light at the slits and recording which slit the electrons came through, and, before looking at that data, look to see if the result shows two discrete bands or an interference pattern… then… If the result is an interference pattern, you might infer that "observing" with a mechanism will not collapse the probability waves… and that it takes a conscious knowing (not just a potentially conscious observation) to collapse the waves. If the results show two discrete bands (showing that the wave probabilities did indeed collapse), and one then erased the data… that would indicate that conscious observation/knowing is not intrinsic to the phenomenon of probability wave collapse… and might suggest that the wave/particles are waves until something specific happens, but discrete particles once something discrete has happened. Has this been done? 

(then after
Heisenberg's uncertainty principle, Born matrixed where stuff might
be; probably / possibly (before it happens, it could be anything possible but once it happens it's that thing thing that happened (so it retrospect it was collapsed possibilities... which is the stuff of what takes place 


i've
thrown in lots of equations. Do I understand them. Hell no. But, mathematics
is of the essense of quantum mechanics... so lets look at the pictures...
The site, "Hyperphysics", say of Schrodinger's equation... 

I do have a poem that relates to "quantum" that I'd like to finish here with... and it goes like this...
in the weave of the world
so that we exist in the in us cultures civilizations
academies oh our visual fields hmm so "knowing" exist
possibly watching 

The discover of "radioactivity" in
the later 19th century, with the observation and concept of "half
lives", of unpredictable occurances, on the one hand, along with
finwely predictable probabilities had introduced probability as a theme…
but not yet as a fundamental aspect of all things and events.
Note" the uncertainty principle is different! It says there is a limit (fundamental and intrinsic) to what we can know. complementary variable the paired qualities are A Thought Experiment: Probability Wave Collapse
Has this been done?
They smashed stuff apart to see what is was made of Things that are conserved (in interactions) momentum linear and angular, charge, and flavbours Things that are conserved ares somehow linked to "symmetries", and symmetries are linked to invariance
(odd # ?) (even # ?) leptons hadrons (nucleons) photons He until it happens it is a probability of what might happen 

* Randall: Warped Passages p.122 