Post by IBDaMann on Mar 27, 2020 6:55:10 GMT
The following is an excerpt of a 27 March 2020 post to The Patriot Hangout:
The concept behind Schrödinger's cat is the problem we face in reaching the limit of what science can tell us, hence we cannot know if the cat is alive or dead without actually checking (in Dorothy's basket in this case). Be prepared to become an instant physicist (and to update your resume):
There are three concepts at play here:
1. The quantum world vs. the macro world. You and I walk around, and live. in the macro world of objects at our scale, e.g. cars, swimming pools, pets, buildings, etc... Physics, on the other hand, gets way down into the quantum world (orders of magnitude lower than the micro world of things visible with microscopes), e.g. photons, electrons, atoms, etc... These things in the quantum world cannot be explained through analogies to things in the macro world. Electrons, for example, need to spin twice completely in order to spin once. Try explaining that to someone such that he can visualize it. Attempts to describe objects in the quantum world is like trying to describe a piece of a jigsaw puzzle while being restricted to only showing the completed puzzle. Yet we try anyway. We portray elementary particles as little round balls. How quaint. I remember the in highschool the discussion about how negative and positive attract, and then the question arising "How can electrons orbit a proton? Why don't electrons which are negative just come crashing down and slam into the proton which is positive?" The answer is that electrons aren't actually little balls that orbit a big proton ball. There are no balls. The moral of the story is that we cannot visualize the quantum world; it is not analagous to our macro world.
2. Heizenberg's Uncertainty Principle. Heizenberg was a smart guy. He noted that we need to measure things in order to know about them and that applies to the quantum world, i.e. we can't know about anything in the quantum world without measuring it. The problem is that we humans only have macro world measuring devices and that the act of measuring, say the momentum of an electron, fundamentally alters the momentum of the electron. Whatever reading you get, the electon no longer has that momentum. Your measuring device necessarily interefered with it in order to get a reading. Heizenberg's Uncertainty Principle states that the more we know about a quantum object's momentum, the less we know about its position and vice versa.
3. Perception vs. Reality. Scientists cannot avoid this topic when reality is something that cannot be perceived directly but rather only relatively or indirectly. When you are in a car that is stopped at a red light that turns green and the driver guns the engine, you can feel yourself being pushed back into your seat, right? Nope. That might be your perception but nothing is pushing you into the seat. The seat is pushing on you but your senses tell you something different. Due to the nature of the quantum world (and here's the funky part) physicists have the strange realization that their perceptions are determining reality as they build science. Physicists define unknown reality in terms of a wave function (bear with me) and that any observations/measurements they make "collapse the wave function" into a reality with a value. Perception, i.e. observation and measurement, affect the reality and determine it.
So, Erwin Schrödinger put those three concepts together in his notional illustration of a (macro world) cat in a box with a (quantum world) measuring device that, depending upon what it measures, either kills the cat or doesn't. Since we cannot know about quantum event without looking at the measuring device, logically we cannot know whether the cat is alive or dead without looking in the box. Either the act of observing the results of the quantum measuring device or observing the cat in the box directly "collapses the wave function" and causes the final result to materialize.
Did you catch that? You and I all want to scream "No, the cat's fate is already determined before we open the box to see" but that is not the approach of theoretical science of the quantum world. This is the concept of Schrödinger's cat. The act of observing/measuring collapses the wave function and establishes reality. The cat in Dorothy's basket is neither alive nor dead until you check. Tell me that doesn't go against every fiber in your body. We insist that reality forms our perceptions, yes? Unfortunately, the quantum world doesn't work that way; it doesn't work like the macro world.
The concept behind Schrödinger's cat is the problem we face in reaching the limit of what science can tell us, hence we cannot know if the cat is alive or dead without actually checking (in Dorothy's basket in this case). Be prepared to become an instant physicist (and to update your resume):
There are three concepts at play here:
1. The quantum world vs. the macro world. You and I walk around, and live. in the macro world of objects at our scale, e.g. cars, swimming pools, pets, buildings, etc... Physics, on the other hand, gets way down into the quantum world (orders of magnitude lower than the micro world of things visible with microscopes), e.g. photons, electrons, atoms, etc... These things in the quantum world cannot be explained through analogies to things in the macro world. Electrons, for example, need to spin twice completely in order to spin once. Try explaining that to someone such that he can visualize it. Attempts to describe objects in the quantum world is like trying to describe a piece of a jigsaw puzzle while being restricted to only showing the completed puzzle. Yet we try anyway. We portray elementary particles as little round balls. How quaint. I remember the in highschool the discussion about how negative and positive attract, and then the question arising "How can electrons orbit a proton? Why don't electrons which are negative just come crashing down and slam into the proton which is positive?" The answer is that electrons aren't actually little balls that orbit a big proton ball. There are no balls. The moral of the story is that we cannot visualize the quantum world; it is not analagous to our macro world.
2. Heizenberg's Uncertainty Principle. Heizenberg was a smart guy. He noted that we need to measure things in order to know about them and that applies to the quantum world, i.e. we can't know about anything in the quantum world without measuring it. The problem is that we humans only have macro world measuring devices and that the act of measuring, say the momentum of an electron, fundamentally alters the momentum of the electron. Whatever reading you get, the electon no longer has that momentum. Your measuring device necessarily interefered with it in order to get a reading. Heizenberg's Uncertainty Principle states that the more we know about a quantum object's momentum, the less we know about its position and vice versa.
3. Perception vs. Reality. Scientists cannot avoid this topic when reality is something that cannot be perceived directly but rather only relatively or indirectly. When you are in a car that is stopped at a red light that turns green and the driver guns the engine, you can feel yourself being pushed back into your seat, right? Nope. That might be your perception but nothing is pushing you into the seat. The seat is pushing on you but your senses tell you something different. Due to the nature of the quantum world (and here's the funky part) physicists have the strange realization that their perceptions are determining reality as they build science. Physicists define unknown reality in terms of a wave function (bear with me) and that any observations/measurements they make "collapse the wave function" into a reality with a value. Perception, i.e. observation and measurement, affect the reality and determine it.
So, Erwin Schrödinger put those three concepts together in his notional illustration of a (macro world) cat in a box with a (quantum world) measuring device that, depending upon what it measures, either kills the cat or doesn't. Since we cannot know about quantum event without looking at the measuring device, logically we cannot know whether the cat is alive or dead without looking in the box. Either the act of observing the results of the quantum measuring device or observing the cat in the box directly "collapses the wave function" and causes the final result to materialize.
Did you catch that? You and I all want to scream "No, the cat's fate is already determined before we open the box to see" but that is not the approach of theoretical science of the quantum world. This is the concept of Schrödinger's cat. The act of observing/measuring collapses the wave function and establishes reality. The cat in Dorothy's basket is neither alive nor dead until you check. Tell me that doesn't go against every fiber in your body. We insist that reality forms our perceptions, yes? Unfortunately, the quantum world doesn't work that way; it doesn't work like the macro world.