We have taken a brief look at the large scale structure and life-cycle of the universe, and have seen how it is effected by the smallest scale quantum effects. We will now examine quantum physics directly. The reader should be warned that quantum reality is often very odd and counter-intuitive, and can be quite complex. That said, we will do our best to explain the relevant concepts, phenomena and characteristics of quantum physics as simply and plainly as possible.
Quantization: The “Pixelation” of the Physical World
The first quantum-mechanical concept we will explore is the first one discovered, and the one from which quantum mechanics derives its name: this is “quantization.” This refers to the discovery that many aspects of the physical world are fundamentally “quantized,” i.e., divided into discrete, discontinuous units. Perhaps the best and most familiar analogy for quantization is the pixelation which is visible in low-resolution digital images, or in essentially any digital image at all which is viewed under sufficient magnification. A digital image ultimately consists of a number of discrete pixels, each with its own color; when viewed as a whole, however, the pixels often become unnoticeable as individual items, and the image seems to represent a single continuous whole.
Quantization was first discovered in the context of the energy of electrons and photons. In essence, this was the discovery that the energy possessed or exhibited by electrons and photons could not exist in any amount at all, but instead could only exist in very particular and discrete amounts.
It was eventually discovered that it was not only energy, but essentially all physical things which were quantized in this way. This even includes space and time! We never notice this quantization or pixelation of space and time in the course of our daily lives simply because the “pixels” of space and time are so unimaginably small. One “pixel” of space is known as a “Planck length” (named after Max Planck, who first suggested that energy may be quantized in 1900) and is roughly 1.6×10-35m long, or about 10-21 times the size of the protons which lie in the heart of an atom! One “pixel” of time, i.e., a “Planck time,” is the amount of time it takes light in a vacuum to traverse a Planck length. This vanishingly small amount of time is about 5.39 x 10-44s.
Non-Locality, Entanglement, and the “Observer Effect”
Another important aspect of quantum mechanics is “non-locality.” Non-locality is most easily explained in the context of pairs of “entangled” particles. (“Entanglement” is also the first type of non-locality which was recognized by physicists.) Entangled particles act much as though they are a single entity, and in which changes which occur in one particle are immediately reflected by corresponding changes in the other, even if the two particles are separated by vast distances in physical space.
One can demonstrate the phenomenon of entanglement using pairs of electrons, for example. If two electrons have become entangled, then a particular property known as “electron spin” becomes correlated between the pair, such that if one of the two is found to be spinning “up” in relation to a particular orientation, then the other will be found to be spinning “down” in relation to the same orientation. A number of very subtle experiments of various kinds have proven that it is not until