Quantum Week - Day 6

I plan to rest on the seventh day, so this will be the last post for Quantum Week. My purpose was similar to a professor who begins his lecture, "Here is my goal. Right now, I'm the only one who doesn't understand quantum mechanics. By the end of the term, you also will not understand." But I'm so far from being a physicist, which has been painfully obvious this past week, that I could only try to let others explain. Hopefully, we widened our island of knowledge and our coastline of ignorance.

In the history of mankind there have been three complete shifts in how we view the underpinnings of the universe. First, the universe was supernatural, then it was mechanical, now it is quantum. I'd like to pay homage to those who discovered and orchestrated this change, …and allowed you to watch this video on a computer smaller than your room.



Of course we also get to curse them for discovering all this weirdness in nature and creating all this messiness in science.

We've spent a week looking at some of this weirdness and messiness. I'll throw a little more at you now for you to ponder:

• The measurement problem is still perplexing. What does measurement mean? You don't need a human. An electronic device will serve—even if it is never looked at.
• By putting a measuring device on one slit, how does a particle traveling through the other slit know?
• It is properly claimed that observing a particle means hitting it, no matter how gently, with light, a photon, which disturbs the particle you are attempting to detect. That is why the system is disturbed. However, there have been other experiments which claim non-demolition measurements. They don't measure using light or photons.
• Measurement needn't be introduced before the particle begins its journey. A measuring device can be introduced later in mid journey and it has the same effect of destroying the interference pattern of probability. (Wheeler's delayed choice experiment)
• Some experiments show that possible measurement will destroy the interference but it can by restored when that possibility is removed. (quantum eraser experiment)
• The interference in the double slit experiment works even for very large molecules.
• Some have said that according to the equations, we should be entering a superimposed state when we measure a superimposed particle.
• There are even triple slit experiments, but they don't add anything new.
• As Professor Balakrishnan said yesterday, even our logic system in regards to the meaning of boolean "and" and "or" must be modified.

So how can nature be so contrary to everything we know?

I'd like to address this question as consolation for not addressing how to interpret the meaning of quantum physics. I'll use a Darwinian approach since that seems to be the current rage to explain anything.

For almost 4 billion years life on earth has reacted to its environment. For a billion years multicellular life used whatever sensing mechanism it had to react to its environment. For 2.5 million years human-like creatures used their senses to learn about their environment. During this time our perception for measuring length, time, and velocity was on a scale of, say, 10 -4 to 10 +4. All that time we were adapting to a relatively minuscule range of nature.

Now, in the last hundred years, we have been experiencing nature on scales of 15 to 30 orders of magnitude smaller or larger. Our whole sensory and logic systems have been developed for millions, if not billions, of years using such a narrow part of nature. No wonder our sense of mystification is great when we come into contact with nature that, to us, is unnatural.

Instead of trying to explain quantum mechanics in classical terms, we should be doing it the other way around, understanding the classical model as an approximation of the underlying quantum world. There's no problem for us to look at the sun's motion and believe that the earth goes around the sun. How else would it look?!