Schrödinger's original Cat places a radioactive substance, Geiger counter, relay, hammer, poison, and cat inside a closed steel chamber and leaves “this entire system” to itself for one hour. The construction is commonly treated as an isolated system. This paper examines what isolation means in the thought experiment. Physical isolation, causal connection, and information available about individual members of a system are different conditions. A comparison with human mortality illustrates the distinction. An actuary may possess individual information such as birthdays and living habits, yet has no probability information about when the first death claim will occur; it may come at any time and at any probability. For radioactive atoms, the standard description supplies no comparable individual information and treats atoms of the same isotope as identical or dismisses their differences for radioactive decay. Schrödinger's Cat therefore raises a question beyond the physical isolation of the steel box: what information about individual radioactive atoms is available to determine the first decay?
Schrödinger's original Cat places a radioactive substance, Geiger counter, relay, hammer, poison, and cat inside a closed steel chamber and leaves “this entire system” to itself for one hour. The construction is commonly treated as an isolated system. This paper examines what isolation means in the thought experiment. Physical isolation, causal connection, and information available about individual members of a system are different conditions. A comparison with human mortality illustrates the distinction. An actuary may possess individual information such as birthdays and living habits, yet has no probability information about when the first death claim will occur; it may come at any time and at any probability. For radioactive atoms, the standard description supplies no comparable individual information and treats atoms of the same isotope as identical or dismisses their differences for radioactive decay. Schrödinger's Cat therefore raises a question beyond the physical isolation of the steel box: what information about individual radioactive atoms is available to determine the first decay?
Schrödinger's Cat has acquired many descriptions and interpretations since its introduction in 1935. This paper returns to Schrödinger's original text and separates what Schrödinger explicitly constructed from what is inferred from the construction. Schrödinger specified a steel chamber, “a tiny amount” of radioactive substance, a Geiger counter, relay, hammer, poison, a one-hour interval, equal possibilities that one atom decays or none does, and “the first atomic decay” as the decisive occurrence. He then described the wave function of the entire system as containing the living and dead cat “mixed or smeared in equal parts.” However, not knowing which of two mutually exclusive states is true, or being unable to rule out either, does not imply that both are physically true. The distinction involves not only Schrödinger's Cat but also Schrödinger's YOU—the observer outside the steel chamber who lacks information. Moreover, the causal chain from atomic decay to the cat's death contains additional physical and biological conditions. The original construction should therefore distinguish the physical cat, its quantum-mechanical description, and the information available to YOU.
Schrödinger's Cat is commonly summarized as a cat that is “both alive and dead until observed.” This paper compares that familiar formulation with Schrödinger's original 1935 construction. The original passage contains a radioactive substance, the possibility that one atom decays or none does, the first atomic decay, a Geiger counter, relay, hammer, poison, and a cat inside a steel chamber. Schrödinger then states that the Psi-function of the entire system contains the living and dead cat “mixed or smeared in equal parts,” followed by a warning against naively accepting a “blurred model” as an image of reality. Several ideas commonly associated with the Cat therefore need to be distinguished: the physical state of the cat, the mathematical description of the system, the probabilities assigned to alternatives, and the information available to an outside observer. The popular Cat is a useful shorthand, but it is not identical to Schrödinger's original Cat.
Schrödinger's original Cat explicitly refers to both “one of the atoms decays” and “the first atomic decay.” This paper examines the first decay occurrence of a finite radioactive sample. Let t₁ denote the time of the first atomic decay. Existing quantities such as half-life, decay constant, mean lifetime, and activity describe radioactive decay collectively, whereas t₁ identifies the first actual decay occurrence of a particular sample. Probability theory contains well-developed treatments of first occurrences, including waiting times, first-arrival times, first-passage times, hitting times, and related stochastic processes. Such treatments require information about the underlying process. This raises two distinct questions for radioactive decay: what information determines the probability distribution of t₁, and what information, if any, determines the actual t₁ of a particular finite sample of a given radioactive isotope before the first decay occurs?
Schrodinger’s cat describes a paradox in which a cat is located in a sealed black box with a poison sealed capsule inside it. Radioactive source decays and emits radiation, which activates a Geiger counter, The Geiger counter generates a signal to release poison from the capsule and kill the cat. Since the decay of a radioactive source is a random sub atomic event, based on quantum mechanics we can only derive a probability-based assumption on the exact time that the decay of the radioactive atom will occur. The Copenhagen interpretation says that until an observer opens the box, the entire system is in superposition and the cat is both dead and alive. In this paper, I will show that we can extrapolate this superposition paradox also to the time domain and the entropy level of the system.
The physicist Erwin Schrödinger described, back in 1935, one aspect of this strange phenomenon. He placed his cat in a sealed box with a piece of radioactive material which might or might not send out a sub-atomic particle. If it did, the Geiger counter was designed to trigger a release of poisonous gas in the box, and thereby kill his cat. The counter was set up to be triggered just enough to give a 50-50 chance of a particle being detected, and therefore the cat an even chance of being poisoned or not. (In those days, this sort of experiment was acceptable, particularly as it was only a thought experiment.) Radioactive behaviour is unpredictable (except in a general, statistical probability kind of way). There is no rule for working out whether or not the Geiger counter will be triggered. If the sub-atomic event does not occur, the cat lives. Otherwise, it dies. Just as a photon (in that famous experiment from ‘real-life’ physics) will quite happily go through both of two parallel slits in a screen – until someone tries to measure or detect it, at which point what the physicists call ‘the collapse of the wave function’ takes place – the particle can both trigger the poison gas and not trigger the poison gas. That is, until someone looks, Schrödinger’s idea is that his cat, for a while, is both alive and dead!
The physicist Erwin Schrödinger described, back in 1935, one aspect of this strange phenomenon. He placed his cat in a sealed box with a piece of radioactive material which might or might not send out a sub-atomic particle. If it did, the Geiger counter was designed to trigger a release of poisonous gas in the box, and thereby kill his cat. The Geiger counter was set up to be triggered just enough to give a 50-50 chance of a particle being detected, and therefore the cat an even chance of being poisoned or not. (In those days, this sort of experiment was acceptable, particularly as it was only a thought experiment.) Radioactive behaviour is unpredictable (except in a general, statistical probability way). There is no way of working out whether or not the Geiger counter will be triggered off. If the sub-atomic event does not occur-the cat lives. Otherwise, it dies. Just as the photon (in Problem 93) will quite happily go through both slits until someone tries to measure or detect it, at which point what the physicists call ‘the collapse of the wave function’ takes place, the particle can both trigger the poison gas and not trigger the poison gas. Until someone looks, Schrödinger’s idea is that his cat, for a while, is both alive and dead!