Introduction to Quantum Weirdness

Quantum Weirdness 

Quantum Electrodynamics (QED) theory has developed to be the theory that defines almost all of the understanding of our physical universe.    It is the most successful theory of our time to describe the way microscopic, and at least to some extent, macroscopic things work.

Yet there is experimental evidence that all is not right.  Some weird things happen at the photon and atomic level that have yet to be explained.  QED gives the right answers, but does not clear up the strange behavior – some things are simply left hanging on the marvelous words “Quantum Weirdness”.   A few examples of quantum weirdness include the reflection of light from the surface of thick glass by single photons, dependent on the thickness of the glass; the apparent interference of single photons with themselves through two paths in double slit experiments; the reconstruction of a polarized photon in inverted calcite crystals, among others.

This paper introduces some ideas that may explain some of the weirdness.

I want to introduce the subject in a way that appeals to the non-scientist public, but also introduce some ideas about what is going on, ideas that may explain some of the weirdness and include a few thoughts about the speed of light and relativity that should stimulate thought on the subject.  Hopefully a few physicists will look in and not be too annoyed with my thoughts.   This will not be a mathematical treatment other than some basic equations from Einstein that most of us are already familiar with.   The later chapters will be more theoretical, but easily understood if I do it justice.   I will include some experimental diagrams and discussion of results.

First let’s review a few facts about one of our most commonly known quantum objects.   Light is a quantum object.  When you see the light from a light bulb it is likely you do not realize that the light you see comes in very tiny packets called photons that are arriving in really huge numbers.   Your nearby 100 watt bulb emits around 250 billion billion photons a second!  A photon can travel unchanged completely across our universe from some distant star or across a few feet from a nearby lamp.   Once emitted, it continues until it hits something that stops it.  It lives a go-splat existence.

When we read this page, we are intercepting some of the billions of photons of light bouncing off the page, those that come off at just the right angle to illuminate rods in the back of our eyes.    Physicists tell us that photons are tiny bits of massless energy that travel at the speed of light.   These bits are indivisible; you can’t split them up into smaller pieces.   In transit they are invisible.

Here are some tidbits of information you will need to know later:

Every photon of a particular frequency has the same intensity (energy).     

If you make the light brighter, you are just making more photons, not changing the energy of the individual photons.  If you make the light very dim, only a few photons are being emitted.  Reduce intensity enough and you can adjust the source to emit one photon at a time, even minutes or hours apart.

The energy and frequency of blue light is higher than that of red light

The energy of each photon is dependent on the frequency of the light but not dependent on the intensity.   A brighter (more intense) light of a particular color is the result of more photons per second, not higher energy in the photons. 

Maybe I can illustrate some of the above this way.  Bird shot is a very small pellet load for a shotgun.  It is small and used for hunting birds.    If you drop a single bird shot pellet from a porch onto a pie pan below, it would make a small sound when it hit.  It would have a certain energy when it hit and every pellet of that size dropped from the same height would have the same energy.  The sound each makes at impact would have the same intensity.  If you dropped a hundred at a time, the energy of each pellet would be the same, but the combined impact and sound intensity would be much higher and louder.  Similarly all red photons hit your eyes with the same energy.  If you step up the current to the light source, the number that hits your eyes goes up accordingly, so you see a higher brightness as the number hitting the rods in your eye each moment is increased.  

Changing from a red photon (light) to a blue one is somewhat like changing from bird shot to buck shot, a much larger pellet.  The blue photon hits harder, as does the buck shot, no matter where it comes from.   

Regardless of color, if you make a light very dim, you can get it down to one photon at a time, sort of like dropping one pellet at a time.   Getting a photon down to one at a time is a bit tricky, much harder than getting a single pellet to pour out of a barrel of pellets, but not impossible.

Photons, unlike shotgun pellets have no mass, but they still have energy.  This energy is transmitted from whatever emitted it to whatever it finally hits.   Thus the photon is an energy carrier in a hurry, always moving at the speed of light.

Next I’ll tell you a little about an easily duplicated experiment using double slits that can be used to prove that light is a wave but also can be used to prove that light is a particle.  It is a good illustration of quantum weirdness.

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2 responses to “Introduction to Quantum Weirdness

  1. This is one of my favorite topics, and you explain it well. I hope you keep writing.

  2. Thank you johnnyolive. Some of my ideas are as weird as the subject. I’ll do my best.

    Oldtimer

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