What is Schrodinger's cat: Definition and 98 Discussions

In quantum mechanics, Schrödinger's cat is a thought experiment that illustrates a paradox of quantum superposition. In the thought experiment, a hypothetical cat may be considered simultaneously both alive and dead as a result of its fate being linked to a random subatomic event that may or may not occur.
This thought experiment was devised by Austrian-Irish physicist Erwin Schrödinger in 1935, in a discussion with Albert Einstein, to illustrate what Schrödinger saw as the problems of the Copenhagen interpretation of quantum mechanics. The scenario is often featured in theoretical discussions of the interpretations of quantum mechanics, particularly in situations involving the measurement problem.

View More On Wikipedia.org
  1. V

    B Are Schrodinger's cat and the double slit experiment the same idea?

    Hello, My highest level of physics is Physics 3 for engineers in college. So I don't have the math or physics background to know this hence the question. I woke up thinking about the double slit experiment and how the simple act of observing somehow interacts or interferes with the...
  2. bushmonk

    I Why don't we bury Schrodinger's Cat?

    What’s with Schrodinger’s Cat? I seem to be missing something. I keep on hearing about Schrodinger’s cat. Why? Why would anyone think that a cat, alive or dead, is in a quantum state? Every quantum experiment involves a quantum state, subject to the law of superposition, being physically...
  3. R

    B Schrödingers cat, is it just mumbo-jumbo?

    If there is a person standing on the opposite side of the closed box with the poor cat containing a poisoning devise, and he can see the cat dying through a transparent window in the box. You stand on the other side of the box and you dont se the cat. What does this mean? Can you now say that...
  4. S

    Quantum entanglement and the Schrödinger experiment

    Ok so just tell me this, if you flip a coin with your eyes closed and it lands on your hand and then you look at the coin and it is heads… there was a time in the duration of the coin being in the air at which the coin was in a state of neither heads or tales. But only once it hits your hand it...
  5. M

    I Schrödinger's astronaut as a quantum computer?

    Consider the following scenario: a space station is put into orbit, which is absurdly well shielded from all sorts of radiation, a.k.a. "a box". You cannot make any effective observation of what the astronaut inside is up to. (This postulate may be implausible, but in the age of "weakly...
  6. entropy1

    I Schrödinger's Cat and radioactive atom

    Particles can be made to be in superposition of their states. Concerning Schrödingers cat, if the cat is in superposition of being dead and alive, does that mean that the atom that drives the narcotic is in superposition of having decayed and not having decayed? And does that mean that any...
  7. O

    B Does Schrödinger's Cat Know Its Own Fate?

    In the Schrödinger's cat thought experiment in its standard configuration, before the experimenter opens the box that contains the cat, has any relevant QM measurement been made by any objects involved in this instance of this experiment? My speculation/understanding: Yes, the cat knows (is...
  8. K

    I Is this system a superposition?

    Suppose a blind man builds a machine that paints three apples with three colors, either red, blue or green. Once the machine has done this, are the three apples in the following superposition: or is the wavefunction just one of It feels like because the man is blind, the apples should be in...
  9. S

    I Doesn't Schrodinger's Cat start to decay?

    In the experiment, if when the box is opened and the cat is dead, won't the cat's body have started to decay and therefore we could determine exactly when it had died. This could have been a long time before we resolved the cat alive / cat dead question by opening the box. Therefore the state...
  10. DaveE

    I Really? Schrödinger's cat again?

    I have a new Physics hypothesis (ok, really Journalism, I guess): Whenever you read anything the features that damn cat, it will be at least misleading, maybe wrong. The worst way to learn about QM is to start by listening to someone talking about quantum cats, it's practically a guarantee that...
  11. S

    I Did Erwin Schrödinger propose that reality could be contradictory?

    Did Schrödinger believe that contradictory or inconsistent things could exist in reality?
  12. bhanum

    B The Cat's Perspective: Can Macroscopic Bodies Be in Superposition?

    Hi, In the Schrodinger's Cat thought experiment, we say that the cat is in a superposition of states of being either dead or alive. But isn't that opinion biased from being outside of the system? From the cat's point of view, it is either dead or alive but never both. The same argument can be...
  13. T

    I Quantum Jumps and Schrodinger's Cat are predictable

    Quantum Jumps are predicted using microwave monitoring. Weird. https://phys.org/news/2019-06-physicists-schrodinger-cat.html
  14. P

    I Interpretation of Schrodinger's Cat

    [Moderator's note: Discussion spun off from another thread.] I guess you don't get the thought experiment then... Schrodinger devised it precisely because it's the inevitable consequences of the standard model of QM, though not with regards to cats specifically due to decoherence (which wasn't...
  15. Demystifier

    A Schrodinger's Cat and the thermal interpretation

    [Moderator's note: spin-off from a previous thread since this discussion is a separate topic.] In this sense, the Schrodinger's famous thought experiment prepares the cat in a superposition of dead and alive. I still don't see how TI can possibly prevent it.
  16. Peter Morgan

    A Schrödinger's cat: what's the state?

    A physicist prepares a box and tells us that in the box there is a cat that is in a superposition of being alive and being dead. How can we be sure whether they're telling the truth? Is the state a superposition or a mixture? If we open the box and measure only whether the cat is alive, using...
  17. entropy2information

    Schrodinger's Cat and The Universe

    I had a question about Schrodinger's cat that extends to the universe. First, I'm sure everyone knows the Schrodinger's cat set up so I won't repeat it. I will just ask, how can the cat be dead or alive prior to measurement? This measurement would be either atoms in the radioactive substance...
  18. George Jones

    How Do Variations on Schrodinger's Cat Reflect Quantum Mechanics in Humor?

    See the cartoons at https://physicsworld.com/wp-content/uploads/2018/09/PWSep18lateral-final-artwork_2400.jpg
  19. S

    I Can Schrodinger's cat apply to things other than alive/dead?

    We know of Schrodinger's cat analogy, where a cat in a box that has a gas tube with deadly gas (or whatever it is) is both alive and dead at the same time until observed. Does it work on anything else? Like something is big or small, near or far, tall or short, red or blue, etc. at the same time...
  20. CharlieCW

    Coherent states in quantum mechanics (Schrödinger Cat)

    Hello. I've been struggling for a day with the following problem on Quantum coherent states, so I was wondering if you could tell me if I'm going in the right direction (I've read the books of Sakurai and Weinberg but can't seem to find an answer) 1. Homework Statement *Suppose a Schrödinger...
  21. J

    I Schrödinger's cat and gravity

    At a high/abstract level, I'm trying to understand how QM treats gravity. What if you set up a Schrödinger's cat experiment so that the cat lost some of its mass when in the "dead" state. So, someone outside the box could "observe" the cat being alive or dead based on change in gravitational...
  22. B

    B Exploring Uncertainty: Schrodinger's Cat and the Nature of Observation

    A cat in a box with a poison that may or may not be released, that hinges on a random event. Until the box is opened, the cat is both dead and alive, until a single state is forced by an observation. Would it be just as valid to pose that the cat and the poison existing in the box is also...
  23. J

    I Find a calculation of Schrödinger's cat experiment?

    Hello, does someone know where to find a calculation of Schrödinger's cat experiment? (like psi(cat)=|dead> + |alive>...)
  24. H

    B Simple intro about Schrödinger's cat metaphor

    Very brief and no math, the author is more about the veracity of checking original sources over retelling pop sci stories. All has been said here previously but scattered over many threads and easy to miss for newbs. Might be helpful to beginners who's only exposure is sensational pop sci...
  25. B

    I I say that this experiment confirms Schrodinger's Cat....

    I'm having a fun little argument with my wife, about an article posted on www.sciencedaily.com. I say that the article CONFIRMS that Schrodinger was RIGHT. My WIFE says that this confirms that Schrodinger is WRONG. The article concerns the quantum techniques used creating the shortest pulse of...
  26. farolero

    B So Schrodinger's cat is a gambler

    ok ill use a cat instead of a person for would be ugly to kill a person even in the imagination though a cat doesn't know how to gamble: shrodinger cat is playing french roulete and every time he loses the life terminating device with a 50% chance is activated what would happen from the...
  27. K

    I Understanding Schrodinger's cat

    (Sorry for my bad English.) I learned something about Schrodinger's equation and 2 and 3 dimensions, as well particle confined in a box and the behavior of the atoms using Schrodinger's analysis. But I don't understand why a superposition of states is necessary* in the Schrodinger's cat...
  28. steveJOBS

    B What is the reason for Schrodinger's cat experiment?

    I'm not sure why schrodinger proposed his cat in a box experiment. Can anyone say why?
  29. W

    I Is Schrodinger's Cat Experiment Possible with Young's Slits and a Switch?

    For the sake of animal lovers, I come up with a variant of Schrodinger's Cat experiment thus: a. in place of the poor cat is a Young's slits setup, with one translucent side of the box doubling as the screen, b. in place of the lethal injection is a switch, c. at a certain fixed time (say 5...
  30. dbcoopersurviv

    I A bit confused about Schrödinger's cat

    I am certain this has been asked before many times before since the cat in the box first did not come out, and I am just overlooking it. And I am using the cat in the box for the exact purpose it was orginally created as I understood, to simplify the concept to its very base pieces to allow...
  31. T

    I What was Niels Bohr's rebuke to Schrödinger's Cat?

    Schrödinger came up with his famous cat experiment in order to attack the Copenhagen interpretation of QM. Since Bohr was the originator of the Copenhagen interpretation, what did he say about Schrödinger's cat? The way it is written in pop culture, many physicists believe that the entire...
  32. durant35

    I Can Decoherence Create a Superposition of Life and Death?

    Hey guys, this is my new thread regarding the problem of decoherence combined with the Schrodinger's cat experiment. If somebody has the patience and isn't annoyed (which is perfectly understandable) I hope that I will get an appropriate answer. So basically I've read Lindley's where does the...
  33. I

    Does Schrödinger's Cat Age If Found Alive?

    Considering only the Copenhagen interpretation, discounting the cat as an observer, and assuming wave function collapse at the time of opening the box - if you find the cat alive, has it aged whilst in the box? Thanks.
  34. Petr Matas

    What if there are no Schrödinger's cats?

    Experiment description: Let us have a slight modification of the famous thought experiment, in which the cat is killed only if a particle decay is detected in a fixed time interval, say from 0 to 1 s. Let the box with the cat, the deadly device, and the radioactive sample with the detector be an...
  35. B

    Isn't Schrodinger's cat doomed anyways?

    I am not a physicist, just a mere electrical engineer (who has off late developed an interest in quantum mechanics). I have a few questions about the Schrodinger cat thought experiment and about whether quantum entangled states can be preserved indefinitely forever, at least theoretically.Please...
  36. Biscuit

    How to prepare for the Feynman Lectures

    I'm in the 11th grade and have little education of college level mathematics. I individually find myself studying one section of it but hardly have a grasp. I really want to read the Feynman Lectures to further my education of physics, but as I read over the pdf it looks like there is a lot of...
  37. quantumfunction

    I Schrodinger's cat, the multiverse and isolated systems

    I know the debate about Schrodinger's cat is usually about things like consciousness but I want to talk about what it might say about isolated systems. Does the wave function of isolated systems remain in a superposition of observable states no matter how large the system gets? Say you have...
  38. Z

    Schrödinger's cat explain color charge?

    I'm doing a science fair project involving trying to explain color charge with the principles behind the Schrödinger cat thought experiment; However I'm having trouble finding the right principle. Its math project was well. Can anyone push me into the right direction
  39. moriheru

    Is the Born Rule the Key to Understanding Schrodinger's Cat Experiment?

    Greetings, Concider the classical setup for the Schrodingercat equation, that is cat in a box some deadly gas or acid isolated in a glas and a hammer that destroys the glas after an uncertain time. Just for some fun consider a new setup: Cat in a box, deadly gas or acid(I think it's blausauere...
  40. T

    Schrodinger's Cat radioactive source

    http://en.wikipedia.org/wiki/Schr%C3%B6dinger's_cat I don't understand, if the radioactive source is put in there then of course the Geiger counter will detect radioactivity so we know the cat must be dead?
  41. V

    Exploring Schrodinger's Cat and Quantum Theory: A Gedankenexperiment

    I'm not going to pretend i know everything about quantum theory nor even part of it. All I have is a incomplete basis of how things work. Please try to bare with me as I describe my gedankenexperiment. Suppose we have the usual set up of schrodinger's cat, A cat in a box that might be either...
  42. T

    Schrödinger's Cat, uncertainty, and observation question

    First of all, from what I've read the descriptions of an observation or measurement in Quantum Mechanics have been quite vague. Since the word measurement is used alternatively I am going to assume that this includes all types of measurements, which brings me to a question. If the box...
  43. J

    Can Schrödinger's Cat's State Be Measured Through Gravity?

    I realize that Schrodinger intended this thought experiment as a way to show how absurd the interpretation of a cat being in two states was. I don't understand how that interpretation can be entertained in the first place due to gravity. Say you were measuring the gravitational field (very...
  44. J

    Schrodinger's Cat vs. The Principle of Explosion

    onsider the following link: http://en.wikipedia.org/wiki/Principle_of_explosion Now, consider Schrodinger's Cat. Does this not imply the following statements? - A) The cat is alive before the box is opened. - B) The cat is not alive before the box is opened. Aren't both of these statements...
  45. StevieTNZ

    Physicist disentangles 'Schrodinger's cat' debate

    As per the title, the article is Physicist disentangles 'Schrodinger's cat' debate The paper is http://arxiv.org/ftp/arxiv/papers/1301/1301.1673.pdf To be quite honest, I don't quite understand what he is trying to say. It looks as though he's trying to make calculations on entangled pairs by...
  46. R

    Is Schrodinger's Cat Truly Both Alive and Dead Until Observed?

    I can't seem to wrap my head around the basic concept of the Schrodinger's cat experiment, the one in which a radioactive particle is either emitted or not emitted, a device is either triggered or not triggered, and the cat is both alive and dead (in a superposition of states) until one of us...
  47. G

    Schrodinger's Cat and looking in the box.

    My knowledge of Quantum Mechanics is not nearly as complete as may be needed to address this problem but I am still curious as to what would happen. As I understand it if we go along with the Schrodinger's Cat thought experiment we can say that the cat is in a state of superposition. And that...
  48. Government$

    Schrodinger's Cat: Exploring Quantum Physics

    I apologize if somebody had already posted this.
  49. bhobba

    Schrodinger's Cat and Leonard Susskind

    Hi Guys For all people interested in Schrodinger's Cat check out Leonard Susskind's explanation - very lucidly explained: http://www.newpackettech.com/Resources/Susskind/PHY30/LectureRv9_Video_Lec7.htm The cat is most definitely not in a superposition - it is entangled with the other...
  50. T

    How can Schrödinger's Cat be both alive and dead?

    Can some one explain to me how the cat can be both alive and dead, I get the principle that since we don't know it is both at the same time because we don't know but in reality it's either alive or alive we just don't know, it's the human factor of sentience just because we don't know doesn't...