Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physics and High Technology

Macroscopic World and Quantum Phenomena: Schrodinger's Cat

Jinhyoung Lee

Published Dec 12, 2012• 0 citations
Publisher

Abstract

As we are accustomed to everyday life, we may find quantum phenomena to be strange. If quantum phenomena were to happen often in our macroscopic world, we would react as if we had seen a ghost. A person to whom we were talking could move to another seat out of our sight in a moment, or his/her face could change. We might question if we are who we are. Fortunately experiencing quantum phenomena in everyday life is extremely hard. However, interestingly, quantum physics predicts that quantum phenomena can occur in the macroscopic world, regardless of our everyday experience. If that prediction is correct, why is experiencing quantum phenomena hard? Such a seemingly contradictory discussion was clearly raised by Schrodinger in his thought experiment, the so-called ‘Schrodinger cat paradox.’ Haroche’s group and Wineland’s group have independently performed experiments on the paradox. In this article, I discuss the historical background and the physical implications of the Schrodinger cat paradox.

DOI
10.3938/phit.21.051

Related papers

Schrödinger’s cat and her laboratory cousins

Anthony J. Leggett

In a famous 1935 paper, Erwin Schroedinger pointed out the apparently bizarre consequences which flow from the assumption that the formalism of quantum mechanics can be extrapolated from the world of electrons and atoms to the level of our own direct consciousness (the “Cat” paradox). In this paper I first discuss some alleged resolutions of the paradox, then point out that the premise is not self-evident, and define a class of alternative (“macrorealistic”) scenarios. I then review the extent to which the experimental predictions of quantum mechanics are currently tested in the direction of the everyday world, and explain a crucial test, yet to be performed, of these predictions vis-a-vis those of macrorealism.

ESI lectures in mathematics and physics•Apr 11, 2013•1 citation

The paradox of Schrodinger's cat

C N Villars

Erwin Schrodinger first described the thought-experiment which has since become known as 'the paradox of Schrodinger's cat' 51 years ago. In recent years, popular accounts of quantum mechanics have tended to adopt one or other of the philosophically most extreme solutions to this paradox, i.e. the consciousness hypothesis or the many worlds interpretation. The author attempts to redress the balance by describing what he takes to be the orthodox solution to the paradox which explains the paradox, without recourse to such counterintuitive notions as a cat simultaneously dead and alive or a universe continually splitting into multiple worlds, as being due to a misapplication of the quantum formalism.

Physics Education•Jul 1, 1986•7 citations

Quantum largesse

In 1935 Erwin Schrödinger proposed a thought experiment to show the absurd consequences of applying quantum mechanics to everyday objects. Schrödinger imagined placing a cat in a box, along with a vial of deadly poison that is connected to a radioactive atom. If the atom decays, it releases the poison and kills the cat. When the box is closed we do not know if the atom has decayed or not, which means that it can be in a "superposition" of two states (decayed and non-decayed) at the same time. Therefore, protested Schrödinger, the cat can be both dead and alive at the same time – which is clearly absurd. There was obviously, he thought, some boundary between the microscopic world of atoms and quantum mechanics, and the macroscopic world of cats and classical mechanics.

Physics World•Aug 1, 2000•0 citations

Schrödinger's cat and her laboratory cousins

A. J. Leggett

In this paper I first briefly review the apparently bizarre consequences of attempting to apply quantum mechanics consistently to macroscopic bodies in certain kinds of situations (the ‘Schrödinger's Cat’ paradox). The paradox results from the assumption that the linear superpositions of macroscopically distinct states, which are unambiguously predicted by the formalism, do indeed exist in nature. Until recently, this assumption was experimentally untested. However, recent advances in techniques of microfabrication, cryogenics and noise control have opened up the possibility of indirect and possibly even direct tests, in particular in superconducting systems incorporating Josephson devices. I describe some of these tests, review the current experimental and theoretical situation and discuss the implications of various possible outcomes to the experiments.

Contemporary Physics•Nov 1, 1984•119 citations

In our mind's eye: Visible and invisible in quantum theory, with Schrödinger's cat experiment

Arkady Plotnitsky

This article aims to reconsider E. Schrödinger's famous thought experiment, the cat paradox experiment, and its place in quantum foundations from a new perspective, grounded in the type of interpretation of quantum phenomena and quantum mechanics, which belongs to the class of interpretations designated here as "reality without realism" (RWR) interpretations. Such interpretations have not been previously brought to bear on the cat experiment, including by N. Bohr, whose interpretation in its ultimate forms (as he changes his interpretation a few times) is an RWR interpretation, but who does not appear to have commented on the cat experiment. The interpretation adopted in this articles follows Bohr's interpretation, as based on two assumptions or postulates, the Heisenberg and Bohr postulates, but it adds a third postulate, the Dirac postulate. The article also introduces, in conjunction with the concept of reality without realism, the concepts of visible and invisible to thought and considers their role in the cat-paradox experiment.

arXiv:2301.11933•Jan 29, 2023•0 citations

Relativity and structure deformations: epistemological aspects

Wojciech Piotr Grygiel

The Schrodinger'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.

Philosophical Problems in Science (Zagadnienia Filozoficzne w Nauce)•Jan 1, 2005•0 citations
As we are accustomed to everyday life, we may find quantum phenomena to be strange. If quantum phenomena were to happen often in our macroscopic world, we would react as if we had seen a ghost. A person to whom we were talking could move to another seat out of our sight in a moment, or his/her face could change. We might question if we are who we are. Fortunately experiencing quantum phenomena in everyday life is extremely hard. However, interestingly, quantum physics predicts that quantum phenomena can occur in the macroscopic world, regardless of our everyday experience. If that prediction is correct, why is experiencing quantum phenomena hard? Such a seemingly contradictory discussion was clearly raised by Schrodinger in his thought experiment, the so-called ‘Schrodinger cat paradox.’ Haroche’s group and Wineland’s group have independently performed experiments on the paradox. In this article, I discuss the historical background and the physical implications of the Schrodinger cat paradox.
In a famous 1935 paper, Erwin Schroedinger pointed out the apparently bizarre consequences which flow from the assumption that the formalism of quantum mechanics can be extrapolated from the world of electrons and atoms to the level of our own direct consciousness (the “Cat” paradox). In this paper I first discuss some alleged resolutions of the paradox, then point out that the premise is not self-evident, and define a class of alternative (“macrorealistic”) scenarios. I then review the extent to which the experimental predictions of quantum mechanics are currently tested in the direction of the everyday world, and explain a crucial test, yet to be performed, of these predictions vis-a-vis those of macrorealism.
Erwin Schrodinger first described the thought-experiment which has since become known as 'the paradox of Schrodinger's cat' 51 years ago. In recent years, popular accounts of quantum mechanics have tended to adopt one or other of the philosophically most extreme solutions to this paradox, i.e. the consciousness hypothesis or the many worlds interpretation. The author attempts to redress the balance by describing what he takes to be the orthodox solution to the paradox which explains the paradox, without recourse to such counterintuitive notions as a cat simultaneously dead and alive or a universe continually splitting into multiple worlds, as being due to a misapplication of the quantum formalism.
In 1935 Erwin Schrödinger proposed a thought experiment to show the absurd consequences of applying quantum mechanics to everyday objects. Schrödinger imagined placing a cat in a box, along with a vial of deadly poison that is connected to a radioactive atom. If the atom decays, it releases the poison and kills the cat. When the box is closed we do not know if the atom has decayed or not, which means that it can be in a "superposition" of two states (decayed and non-decayed) at the same time. Therefore, protested Schrödinger, the cat can be both dead and alive at the same time – which is clearly absurd. There was obviously, he thought, some boundary between the microscopic world of atoms and quantum mechanics, and the macroscopic world of cats and classical mechanics.
In this paper I first briefly review the apparently bizarre consequences of attempting to apply quantum mechanics consistently to macroscopic bodies in certain kinds of situations (the ‘Schrödinger's Cat’ paradox). The paradox results from the assumption that the linear superpositions of macroscopically distinct states, which are unambiguously predicted by the formalism, do indeed exist in nature. Until recently, this assumption was experimentally untested. However, recent advances in techniques of microfabrication, cryogenics and noise control have opened up the possibility of indirect and possibly even direct tests, in particular in superconducting systems incorporating Josephson devices. I describe some of these tests, review the current experimental and theoretical situation and discuss the implications of various possible outcomes to the experiments.
This article aims to reconsider E. Schrödinger's famous thought experiment, the cat paradox experiment, and its place in quantum foundations from a new perspective, grounded in the type of interpretation of quantum phenomena and quantum mechanics, which belongs to the class of interpretations designated here as "reality without realism" (RWR) interpretations. Such interpretations have not been previously brought to bear on the cat experiment, including by N. Bohr, whose interpretation in its ultimate forms (as he changes his interpretation a few times) is an RWR interpretation, but who does not appear to have commented on the cat experiment. The interpretation adopted in this articles follows Bohr's interpretation, as based on two assumptions or postulates, the Heisenberg and Bohr postulates, but it adds a third postulate, the Dirac postulate. The article also introduces, in conjunction with the concept of reality without realism, the concepts of visible and invisible to thought and considers their role in the cat-paradox experiment.
The Schrodinger'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.