Thursday, May 14, 2020

The Certainty of Uncertainty

Or, why "Schrodinger's cat is both alive and dead". 

You might read this musing because I think the title made you curious.  Actually you have always been curious about a lot of things since that is one of those attributes that define us.  Of course, we are more than just that.  We are aware that although  many other living things actually exhibit the same traits, including the cat, we are different.  The huge difference being that humans have sustained and built up on their curiosity from generation to generation.  Curiosity generated questions, we found answers, lots of them, in fact, but we did not stop there.  We compiled those answers, we built  up knowledge and each generation became smarter than the one before it.  In other words, today we are at that tip of human development where we can claim superiority in knowledge and technology over every generation since recorded history. Our dominance over other living things even became petty sometimes that one among us sometime ago coined the phrase, "Curiosity kills the cat", although  such attribution to the unfortunate feline has no basis in fact.  

However, though we've been told that knowledge is power, the more we know the more we don't know.  Put another way, the more we know the more questions we generate; followed by the more ways we know what and how to ask.  The questions too became more complex and in many cases, it seems, became impossible to answer but the well of unanswered questions keeps getting deeper.

One Nobel Prize-winning Austrian named Erwin Schrodinger, born in August 1887, who died in 1961, tried to answer one of the deepest mysteries on the nature of matter.  He was not alone by any means but it was his experiment on the cat where this musing came from - Schrodinger's Cat .  Before we go any further, I will have the reader know that not a single cat died or had been harmed in any way because of Schrodinger's experiment. They were thought-experiments after all, a practice also made famous by one of his contemporaries who was born almost ten years earlier in March 1879 - Albert Einstein.

Let me first propose this modern day thought-experiment:

You've been having some difficult decisions lately.  You felt your career was heading at a dead end, you seem to be stuck at the same job that is getting less and less challenging.  Unfortunately, there seems to be no signs that you will go anywhere within the company and worse, you are not being acknowledged for what you've contributed, so far, and clearly not being recognized for your higher potentials. You like the company and would like to stay for the long term but that did not keep you from looking outside.  In fact, you have at the moment a standing offer from another company that wants to hire you.

Just about now, your boss's secretary called. Your boss wants to see you - right away! It must be about that most recent project you worked on that you've been waiting for a feedback from her.  Aside from the countless hours you put into this one work, this was, you believed, your finest yet, where you poured much energy and time you could muster.  You believed that how the project was received and assessed by the powers-that-be could make or break your prospect to get that next promotion that is opening up.  But you don't know.  In fact, you didn't have a clue as to what you were being summoned for.

Now, there you are in front of  your boss's office door before entering and you wondered. Is she going to tell me I did a great job?  I'm moving on to a higher level job.  Or, that's it, I'm done for.  That was the last project she will trust you to do.  In fact, you were good as done within the company.

You had two speeches ready to use because you really prepared this time.  You had a nice thank you speech and another that said, "Well, I'll have you know this is the last time you talk to me this way because I quit.  Goodbye. 

But until you enter that office and hear what your boss had to say, you didn't really know what was going to happen.  You were going to have that promotion or some such similarly happy and astounding great news or you were going to bid your bitter farewell.  Until then you really did not know.  

Now, readers, you all know you've been through similar such predicaments of lesser or more significance than that.  Many probabilities until "that or this one" happened or you're left wondering "what if I did this instead of the other".  So many "what ifs" and "if only" this or that, etc.

Since the time we were made aware of the sense of past, present and future and we were able to philosophize about them, we realized immediately that the future are like droplets in a cloud of  mere probabilities before each of them collapses except the one that actually occurred.  This is what we refer to as the classical sense of reality, based on rules and laws that are according to the classical laws of physics.  Don't roll your eyes upon reading "physics".  I promise this will not be complicated or painful.  

Isaac Newton gave us his laws of motion and inertia and other derivatives which not only explained gravitational effects of objects on others, the motions of planets and comets but more importantly the same principles took us from the earth to the moon and back. All that it took was to know where everything was in the solar system and applying the laws prescribed by Newton on how objects will move. And since we knew where the moon will be at a particular time  and where the earth was going to be later, we were able to plot the trajectory of the entire trip  for the astronauts to land on the moon and return safely  back to earth.

For several generations Newton's laws and principles worked in sync with our idea of reality. Then Albert Einstein showed up.  He not only modified some of Newtons' views of the world, he actually proved Newton was wrong on the fundamental nature of gravity and time.

But Einstein too would be dealt with the same fate.  Newton was long gone before his principles were "corrected" while Einstein was still alive and well and actively and intellectually involved before he too found out he was wrong  on a few of his ideas.  Edwin Hubble showed him a universe farthest (literally) from his idea of what it was and much larger than he imagined it to be. Then he had contemporaries, like Schrodinger and Niels Bohr and Max Planck who devoted their time on the world of the very small, who showed Einstein that in a world smaller than those of viruses his much adored ideas did not work, or were actually irrelevant.

In the world of the very very small, inhabited by sub-atomic particles, the rules of the macro world don't apply.  Not only that electrons and other inhabitants of that world deal with different rules, they exhibit the weirdest behavior that only another branch of physics can explain or, at least attempt to explain.  Max Planck gave us a different world view that is so weird and different that it could very well be an entirely different universe.

Sub atomic particles ruled that world.  It became known as the quantum world and please  don't roll your eyes, again.  Why does that matter? If not for the laws of quantum physics you will not be reading this from your electronic devices, nor will you be able to call your friends, loved ones and colleagues, and the GPS in your car will not work. A lot of the things you use or avail of their  utilities are courtesy of quantum physics.  Even the very light that is generated by the hot filament of an ordinary incandescent light, fluorescence and LED propagation of light, X-rays, magnets, TV and radar and lasers all fall under the spell of quantum mechanics.

But what has all of these got to do with the cat?  Particularly Schrodinger's cat.  Schrodinger was aware of the complexity that the new science was preaching and realized how difficult it was to explain to the ordinary layperson like you and me and even to himself and his fellow physicists.  Even Old Albert didn't like it.  

Schrodinger envisioned and he wanted us to imagine with him a cat inside a completely sealed box.  Inside with the cat is a Geiger counter and a radioactive material that had a 50-50 chance of decaying or not. If it did decay it will trigger the Geiger counter's needle which will open a vial of poisonous gas.  If that happened the cat will die.  If it didn't the cat will be alive and well.  You will only know that if you opened the box.  Why did Schrodinger do that thought-experiment?

He puzzled over the idea that an electron can be a particle or a wave. It will be either, depending on how you observe or measure it.  In fact, an electron, through quantum rules, will behave differently if you are looking and another way if you are not. Weird but true.

The now famous double-slit experiment which was first performed by Thomas Young, an English scientist two hundred years ago, is an actual test that most college physics majors get to do routinely or by anyone interested, really.  You can check it out later (through the links below) but what it is all about is that a single particle, like an electron, will seem to pass through two slits at the same time.  Or, if observed differently, it will only pass through one slit at a time but never simultaneously.  Weird but true. Again.

That is the world of quantum physics that Schrodinger was telling his fellow scientists.  But he went further and said that until you opened the box the cat was both dead and alive.  Not really referring to an actual cat but to say that in the quantum world the inhabitants there exist as waves and particles but once observed a certain way, they will be one or the other. 

One may ask, what if we put a closed circuit camera inside the box with the cat? As thought-experiments go, you just introduced an observer hence you also changed the conditions, as if you have already opened the box, so the paradox no longer exists.

Applied to our classical sense of reality, when you wake up each morning you may have several options on what to have for breakfast, what to wear, what route to take to go to a few places you had in mind but all of those are just mere probabilities until you pick the ones you did, but keep in mind that as you pick one, it affects all the ones that follow, ad infinitum.

What is really happening?  We know that electrons and us and koala bears and earthworms inhabit the same universe, so why different sets of rules for particles and a different ones for anything the size of and bigger than a virus?  That is what had been bugging Schrodinger and everyone like him, particularly, German physicist Werner Heisenberg, who came up with his famous uncertainty principle.  In classical reality, for example, the more we know about a moving car the more we know about how fast it is going and where it is heading.  Not in the sub-atomic world where nothing has a definite position, a definite trajectory, or a definite momentum so, "Trying to pin a thing down to one definite position will make its momentum less well pinned down, and vice-versa".  Fortunately, it is not the case in our "normal" sense of reality. The question is why?

It remains true, therefore, that there simply are going to be a lot of things we will never know or understand.  It is as if God had put limits to our ability to know or understand everything.  I think we can leave it at that and accept the fact that hard as we try there will always be lots and lots of stuff we don't know.  

A man may have given up trying to read his wife's mind because he knows that is impossible but swears that he knows what his fellow dude is about to do.  On the other hand the wife knows and can read her husband's mind like an open book.  An astrologer can plot your fate based on the positions of the stars and planets on the day you were born but can't tell you where the stock market is going to be tomorrow or forecast the weather for the week.  Someone, by way of an explanation, actually thought that this must be a "quantum thing".

After all of the amount of time I spent to craft this musing, and all the mental stimulation (I hope) you may have derived from it, it actually boils down to the melody and lyrics sung by Doris Day from an Alfred Hitchcock movie made in 1956 which she co-starred with James Stewart.  

The song was "Que Sera Sera". Spanish for, "What will be, will be". Or, "Quod erit, erit", in Latin.


Rather than point you to scientific papers or even Scientific American, there was an article in Popular Mechanics that explains the whole thing with clarity, "The Logic-Defying Double-Slit Experiment Is Even Weirder Than You Thought" (link below)

https://www.yahoo.com/tech/logic-defying-double-slit-experiment-64411873.html

Or, you can just simply type on your search bar, "the double slit experiment YouTube"




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