So … the other night I was watching TV. Specifically, I was watching a Big Bang Theory rerun. At the point when I tuned in, Leonard and Penny have just returned from their first date. Leonard asks Penny if she has ever heard of Schrodinger’s Cat. Penny grimaces, and says, that she has heard too much about the cat. (Apparently Schrodinger’s Cat has been a recurrent topic among the boys and Penny throughout the episode.) Leonard then proclaims that the cat is alive, and kisses Penny. All is well – or at least as well as things get between Leonard and Penny in the series – until Leonard notices the video camera that Howard and Raj have installed so that they can watch the good night moments between Leonard and Penny, but that is another tale. So the mention of Schrodinger’s Cat got set off a resonance of familiarity for me, but got me to wondering about what the story was with the cat.
Then , the very next morning (August 12, 2013) I opened my computer, went to Google, and I saw an image celebrating Erwin Schrodinger’s 126th birthday!
There are no coincidences. So I figured that it was meant to be that I should compile a blog about Schrodinger’s cat! And here you have it – thanks to Google and Wikipedia ….
First you need to know that while Schrodinger’s cat is real, it does not now, nor has it ever actually existed. That being said, Schrödinger’s cat is what folks call a thought experiment. It could also be understood as a paradox. Schrodinger’s cat was devised by the Austrian physicist Erwin Schrödinger back in 1935. Erwin used the story about the cat to illustrate what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects, an application of quantum mechanics that often resulted in contradictions with common sense. (Don’t buzz out on me this is about the cat not quantum mechanics.)
The Copenhagen interpretation is one of the earliest (1924–27) and most commonly taught interpretations of quantum mechanics. In essence it says that quantum mechanics does not give a description of objective reality but deals only with probabilities. And, the Copenhagen interpretation also proposed that the act of measurement causes the set of probabilities to immediately and randomly assume only one of the possible values. If you are into name dropping, the names associated with the Copenhagen interpretation include devised by Niels Bohr and Werner Heisenberg.
So … Schrodinger’s cat scenario describes the circumstances of a cat that may be both alive and dead, depending on an earlier random event. (Of course while the original “experiment” was imaginary, similar principles have been implemented, examined and used in practical applications.) In the course of developing this experiment, Schrödinger coined the term Verschränkung (entanglement). Schrodinger asked folks (that would be us) to imagine that a cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter, there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, that a bit of radioactive substance does decay, the Geiger counter tube sets into action and through a relay releases a hammer that shatters a small flask of hydrocyanic acid which would kill the cat. (Clearly this thought experiment was devised before the days of the SPCA and PETA!) If you have left this entire system to itself for an hour, you could say that the cat still lives if no atom has decayed. Mathematical description of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts.
In effect, this thought experiment poses the question, ‘when does a quantum system stop existing as a superposition of states (a superposition of states is when both/and are taken to exist concurrently and at the same time) and become one or the other?’ So, when does the cat stop being alive AND dead, and become either dead or alive? If the cat survives, it remembers only being alive. If the cat dies, it remembers nothing – at least that is what we seem to believe about cats and their afterlife.
The thought experiment illustrates an apparent paradox. Our intuition says that no observer can be in a mixture of states—yet the cat, it seems from the thought experiment, can be such a mixture. Is the cat required to be an observer, or does its existence in a single well-defined classical state require another external observer? Each alternative seemed absurd to Albert Einstein, who was impressed by the ability of the thought experiment to highlight these issues. In a letter to Schrödinger dated 1950, he wrote:
“You are the only contemporary physicist, besides Laue, who sees that one cannot get around the assumption of reality, if only one is honest. Most of them simply do not see what sort of risky game they are playing with reality—reality as something independent of what is experimentally established. Their interpretation is, however, refuted most elegantly by your system of radioactive atom + amplifier + charge of gunpowder + cat in a box, in which the psi-function of the system contains both the cat alive and blown to bits. Nobody really doubts that the presence or absence of the cat is something independent of the act of observation.”
Suffice it to say that within the realms of science and literature there are many detailed interpretations of this thought experiment. Superpositions of the states of the cat – the cat is both alive and dead – are possible only until there is observation. But, does the cat count as an observer? And of course there is the post modern observation that if the cat is not observed within a period of time it will be dead from lack of food. And … there is no mention of kitty litter in the statement of the thought experiment … and … both science and literature are rich with interpretations.
Go, explore. Think seriously. Think with a clear and critical mind. Think with a light and open heart. Think about how this might apply to how we live our lives, to how we perceive and think about ourselves and each other.
Think about being alive and dead at the same time… think about both/and possible conditions. Maybe some people, maybe ALL people really can be both good AND bad at the same time and the way they appear to us really is an artifact of our observation? Remember the story of the Native American Grandmother and the compassionate and evil wolfs that live in each of us? And which lives? The one we feed, the one we observe and attend to! Elizabeth Kubler Ross was fond of saying that we all, each of us carry within our soul’s both Hitler and Mother Teresa – who we become is who we observe and attend to and nurture.
Remember the Thomas Theorem: situations perceived as real are real in their consequences. What you see – what you expect to see – is what you get. Be aware of your expectations. Be awake, be aware.
So … who will you be? What will you observe and build in your world. No, this is not a call for everyone to become Pollyanna. But it is a reminder that what you see may well be what you get, and that there is more choice than we realize in what we see.
Go forth my friends, nurture your sense of wonder at the world through which you wander. Never hurry by an open door. Never hurry by an opportunity for kindness and compassion. Keep an open heart, a giving hand, and a shoulder firmly pressed to the work of fairness and respect for human dignity.
One thought on “thinking about Schrodinger’s cat”
Interesting, provocative, and just plain lovely conclusion. I always tell social work students when we talk about reflexivity that there are at least four people living in me. I am the one that I choose to listen to. Let’s hope I make good choices.