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arXiv:2106.09705 · Journal of Physics B Atomic Molecular and Optical Physics

How to administer an antidote to Schrödinger’s cat

Juan-Rafael Álvarez, Mark IJspeert, Oliver Barter, Ben Yuen, Thomas D. Barrett, Dustin Stuart, Jerome Dilley, Annemarie Holleczek, Axel Kuhn

Published Feb 17, 2022• 4 citations

Abstract

Abstract In his 1935 Gedankenexperiment, Erwin Schrödinger imagined a box with a cat and a poisonous substance which has a 50% probability of being released, based on the decay of a radioactive atom. As such, the life of the cat and the state of the poison become entangled, and the fate of the cat is determined upon opening the box. We present an experimental technique that keeps the cat alive on any account. This method relies on the time-resolved Hong–Ou–Mandel effect: two long, identical photons impinging on a beam splitter always bunch in either of the outputs. Interpreting the first photon detection as the state of the poison, the second photon is identified as the state of the cat. Even after the collapse of the first photon’s state, we show their fates are intertwined through quantum interference. We demonstrate this by a sudden phase change between the inputs, administered conditionally on the outcome of the first detection, which steers the second photon to a pre-defined output and ensures that the cat is always observed alive.

DOI: 10.1088/1361-6455/ac5674

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Abstract In his 1935 Gedankenexperiment, Erwin Schrödinger imagined a box with a cat and a poisonous substance which has a 50% probability of being released, based on the decay of a radioactive atom. As such, the life of the cat and the state of the poison become entangled, and the fate of the cat is determined upon opening the box. We present an experimental technique that keeps the cat alive on any account. This method relies on the time-resolved Hong–Ou–Mandel effect: two long, identical photons impinging on a beam splitter always bunch in either of the outputs. Interpreting the first photon detection as the state of the poison, the second photon is identified as the state of the cat. Even after the collapse of the first photon’s state, we show their fates are intertwined through quantum interference. We demonstrate this by a sudden phase change between the inputs, administered conditionally on the outcome of the first detection, which steers the second photon to a pre-defined output and ensures that the cat is always observed alive.

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!

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.

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 of the wave function to entropy level, to the fabric of space – time, to the information paradox of black holes, new dimensions and to the multiverse theory.

The Schrödinger's Cat paradox was proposed in 1935 by Edwin Schrodinger, one of the founders of quantum mechanics, as an attempt to visualize the macroscopic realization of a quantum superposition state. A cat is placed in a sealed box together with a vial of poison. A two-state particle (e.g. an electron) is sent into a detector in the box resulting either in a broken or an intact vial and a dead or live cat, respectively. The main problem consists in whether the superposition state of a microscopic particle can be transferred upon the macroscopic cat, that is, whether the cat can exist in a superposition state, being simultaneously dead and alive. Since the standard Copenhagen interpretation is unable to assign any reality to the quantum superposition state, the paradox finds no resolution within the regime of this interpretation. Von Neumann's insistence on the uniform treatment of both microscopic (quantum) and macroscopic (classical) objects according to the laws of quantum mechanics provides a more consistent framework for the resolution of the paradox. In particular, the discovery of the phenomenon of decoherence, whereby the disappearance of the quantum interferences at the macro level is accounted for, suggests the onset of an extremely efficient interference relaxation process (10-23 s) upon the interaction of the two state particle with the detector. As a result, Schrodinger's cat can exist macroscopically either as dead or alive and never as a combination of both. Decoherence not only aids the resolution of the Schrodinger's Cat paradox but also sheds light upon the mechanisms by which the macro-world emerges from the microscopic quantum realm.