薛定谔的猫

本词条由Solitude初步翻译。

模板:Other uses
模板：其他用途

模板：简短说明 由物理学家欧文·薛定谔设计的思维实验

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模板：需要更多的引用

文件:Schrodingers cat.svg

Schrödinger's cat: a cat, a flask of poison, and a radioactive source are placed in a sealed box. If an internal monitor (e.g. Geiger counter) detects radioactivity (i.e. a single atom decaying), the flask is shattered, releasing the poison, which kills the cat. The Copenhagen interpretation of quantum mechanics implies that after a while, the cat is simultaneously alive and dead. Yet, when one looks in the box, one sees the cat either alive or dead, not both alive and dead. This poses the question of when exactly quantum superposition ends and reality collapses into one possibility or the other.

文件：薛定谔的猫：将一只猫，一瓶毒药和放射源放置在密封的盒子里。如果内部监测器（例如盖革计数器Geiger counter）检测到放射性（即单个原子衰变），则烧瓶会破碎，释放出毒药，从而杀死猫。量子力学的哥本哈根诠释Copenhagen interpretation表明，一段时间之后，这只猫既是死的又是活的。然而，当人们往箱子里看时，看到的猫不是活着的就是死了的，而不是既活着又死了的猫。这就提出了一个问题，即确切的量子叠加何时结束而现实何时坍缩成一种或另一种可能性。

Schrödinger's cat: a cat, a flask of poison, and a [[radioactive source are placed in a sealed box. If an internal monitor (e.g. Geiger counter) detects radioactivity (i.e. a single atom decaying), the flask is shattered, releasing the poison, which kills the cat. The Copenhagen interpretation of quantum mechanics implies that after a while, the cat is simultaneously alive and dead. Yet, when one looks in the box, one sees the cat either alive or dead, not both alive and dead. This poses the question of when exactly quantum superposition ends and reality collapses into one possibility or the other.]]

薛定谔的猫：将一只猫，一瓶毒药和放射源放置在密封的盒子里。如果内部监测器（例如盖革计数器）检测到放射性（即单个原子衰变），则烧瓶会破碎，释放出毒药，从而杀死猫。量子力学的哥本哈根诠释Copenhagen interpretation表明，一段时间之后，这只猫既是死的又是活的。然而，当人们往箱子里看时，看到的猫不是活着的就是死了的，而不是既活着又死了的猫。这就提出了一个问题，即确切的量子叠加何时结束而现实何时塌陷成一种或另一种可能性。

Schrödinger's cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935, though the idea originated from Albert Einstein. It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects. The scenario presents a hypothetical cat that may be simultaneously both alive and dead, It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects. The scenario presents a hypothetical cat that may be simultaneously both alive and dead, a state known as a quantum superposition, as a result of being linked to a random subatomic event that may or may not occur.

}}</ref> a state known as a quantum superposition, as a result of being linked to a random subatomic event that may or may not occur.

} / ref 一种被称为量子叠加的状态，是与可能或不可能发生的随机亚原子时间相联系的结果。

The thought experiment is also often featured in theoretical discussions of the interpretations of quantum mechanics, particularly in situations involving the measurement problem. Schrödinger coined the term Verschränkung (entanglement) in the course of developing the thought experiment.模板:Quantum mechanics

The thought experiment is also often featured in theoretical discussions of the interpretations of quantum mechanics, particularly in situations involving the measurement problem. Schrödinger coined the term Verschränkung (entanglement) in the course of developing the thought experiment.

思维实验也经常出现在量子力学诠释的理论讨论中，特别是在涉及测量问题的情况下。薛定谔在开发思想实验的过程中创造了“纠缠”这个术语。

==Origin and motivation==
起源

A life-size—and moveable—cat figure in the garden of Huttenstrasse 9, Zurich, where Erwin Schrödinger lived 1921–1926. A visitor to the house cannot know in advance where the cat will be.

埃尔温·薛定谔1921年至1926年间在苏黎世所居住的Huttenstrasse 9号的花园里有一个真人大小、可移动的猫形雕像。来这里拜访的客人是无法提前知道猫的位置的。 A life-size—and moveable—cat figure in the garden of Huttenstrasse 9, Zurich, where Erwin Schrödinger lived 1921–1926. A visitor to the house cannot know in advance where the cat will be.

埃尔温·薛定谔1921年至1926年间在苏黎世所居住的Huttenstrasse 9号的花园里有一个真人大小、可移动的猫形雕像。来这里拜访的客人是无法提前知道猫的位置的。

Schrödinger intended his thought experiment as a discussion of the EPR article—named after its authors Einstein, Podolsky, and Rosen—in 1935. The EPR article highlighted the counterintuitive nature of quantum superpositions, in which a quantum system such as an atom or photon can exist as a combination of multiple states corresponding to different possible outcomes.

Schrödinger intended his thought experiment as a discussion of the EPR article—named after its authors Einstein, Podolsky, and Rosen—in 1935. The EPR article highlighted the counterintuitive nature of quantum superpositions, in which a quantum system such as an atom or photon can exist as a combination of multiple states corresponding to different possible outcomes.

薛定谔打算把他的思维实验作为对 EPR 文章（以其作者爱因斯坦、波多尔斯基和罗森的名字命名）的讨论在1935年进行了讨论。EPR文章强调了量子叠加的反直觉性质，在量子叠加中，一个量子系统，比如原子或者光子，可以作为对应不同可能结果的多个状态的组合而存在。

The prevailing theory, called the Copenhagen interpretation, says that a quantum system remains in superposition until it interacts with, or is observed by the external world. When this happens, the superposition collapses into one or another of the possible definite states. The EPR experiment shows that a system with multiple particles separated by large distances can be in such a superposition. Schrödinger and Einstein exchanged letters about Einstein's EPR article, in the course of which Einstein pointed out that the state of an unstable keg of gunpowder will, after a while, contain a superposition of both exploded and unexploded states.

The prevailing theory, called the Copenhagen interpretation, says that a quantum system remains in superposition until it interacts with, or is observed by the external world. When this happens, the superposition collapses into one or another of the possible definite states. The EPR experiment shows that a system with multiple particles separated by large distances can be in such a superposition. Schrödinger and Einstein exchanged letters about Einstein's EPR article, in the course of which Einstein pointed out that the state of an unstable keg of gunpowder will, after a while, contain a superposition of both exploded and unexploded states.

流行的理论是被称为哥本哈根诠释的理论，它认为量子系统在与外部世界相互作用或被外部世界观察之前一直处于叠加状态。发生这种情况时，叠加态会坍缩成一种或多种可能的定态。电子顺磁共振(EPR)实验表明，具有多个相距较远距离的多个粒子的系统可能处于这种叠加状态。薛定谔和爱因斯坦就爱因斯坦的 EPR 文章互相通信。在此过程中，爱因斯坦指出，不稳定的火药桶的状态会在一段时间后包含爆炸状态和未爆炸状态的叠加。

To further illustrate, Schrödinger described how one could, in principle, create a superposition in a large-scale system by making it dependent on a quantum particle that was in a superposition. He proposed a scenario with a cat in a locked steel chamber, wherein the cat's life or death depended on the state of a radioactive atom, whether it had decayed and emitted radiation or not. According to Schrödinger, the Copenhagen interpretation implies that the cat remains both alive and dead until the state has been observed. Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; on the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics.

To further illustrate, Schrödinger described how one could, in principle, create a superposition in a large-scale system by making it dependent on a quantum particle that was in a superposition. He proposed a scenario with a cat in a locked steel chamber, wherein the cat's life or death depended on the state of a radioactive atom, whether it had decayed and emitted radiation or not. According to Schrödinger, the Copenhagen interpretation implies that the cat remains both alive and dead until the state has been observed. Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; on the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics.

为了进一步说明，薛定谔描述了如何在原则上通过依赖于叠加状态的量子粒子在大型系统中创建叠加状态。他提出了一种在封闭的钢制房间中放置猫的方案，其中猫的生死取决于放射性原子的状态。根据薛定谔的说法，哥本哈根诠释意味着这只猫在被观察到之前既是活的也是死的。薛定谔并不希望将死猫和活猫的概念大肆宣扬，相反，他希望通过这个例子来说明现有量子力学观点的荒谬性。

——Solitude（讨论）该句意译 

However, since Schrödinger's time, other interpretations of the mathematics of quantum mechanics have been advanced by physicists, some of which regard the "alive and dead" cat superposition as quite real. Intended as a critique of the Copenhagen interpretation (the prevailing orthodoxy in 1935), the Schrödinger's cat thought experiment remains a defining touchstone for modern interpretations of quantum mechanics. Physicists often use the way each interpretation deals with Schrödinger's cat as a way of illustrating and comparing the particular features, strengths, and weaknesses of each interpretation.

However, since Schrödinger's time, other interpretations of the mathematics of quantum mechanics have been advanced by physicists, some of which regard the "alive and dead" cat superposition as quite real. Intended as a critique of the Copenhagen interpretation (the prevailing orthodoxy in 1935), the Schrödinger's cat thought experiment remains a defining touchstone for modern interpretations of quantum mechanics. Physicists often use the way each interpretation deals with Schrödinger's cat as a way of illustrating and comparing the particular features, strengths, and weaknesses of each interpretation.

但是，自从薛定谔时代以来，物理学家对量子力学数学进行了其他解释，其中一些解释认为“活死”的猫叠加是十分真实的。作为对哥本哈根诠释的批判(1935年盛行的正统观念) ，薛定谔的猫思维实验仍然是现代量子力学诠释的决定性的试金石。物理学家经常使用每种解释处理薛定谔猫的方式来说明和比较每种解释的特点、优缺点。

==Thought experiment==
思维实验

Schrödinger wrote:

Schroedinger: "The Present Situation in Quantum Mechanics." 5. Are the Variables Really Blurred?</ref>

Https://archive.is/20121204184041/http://www.tuhh.de/rzt/rzt/it/qm/cat.html#sect5 · 施罗丁格: 《量子力学现状》5.变量真的模糊了吗？] / ref

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在这些情况下，原本局限于原子域的不确定性变成了宏观的不确定性，这种不确定性可以通过直接观察得到解决，这是很典型的。这使我们无法如此天真地接受一个代表现实的“模糊模型”是有效的。就其本身而言，它不会包含任何不清晰或矛盾的内容。摇晃或失焦的照片与云和雾堤的快照是有区别的。}

Schrödinger's famous thought experiment poses the question, "when does a quantum system stop existing as a superposition of states and become one or the other?" (More technically, when does the actual quantum state stop being a non-trivial linear combination of states, each of which resembles different classical states, and instead begin to have a unique classical description?) If the cat survives, it remembers only being alive. But explanations of the EPR experiments that are consistent with standard microscopic quantum mechanics require that macroscopic objects, such as cats and notebooks, do not always have unique classical descriptions. The thought experiment illustrates this apparent paradox. Our intuition says that no observer can be in a mixture of states—yet the cat, it seems from the thought experiment, can be such a mixture. Is the cat required to be an observer, or does its existence in a single well-defined classical state require another external observer? Each alternative seemed absurd to Einstein, who was impressed by the ability of the thought experiment to highlight these issues. In a letter to Schrödinger dated 1950, he wrote:

Schrödinger's famous thought experiment poses the question, "when does a quantum system stop existing as a superposition of states and become one or the other?" (More technically, when does the actual quantum state stop being a non-trivial linear combination of states, each of which resembles different classical states, and instead begin to have a unique classical description?) If the cat survives, it remembers only being alive. But explanations of the EPR experiments that are consistent with standard microscopic quantum mechanics require that macroscopic objects, such as cats and notebooks, do not always have unique classical descriptions. The thought experiment illustrates this apparent paradox. Our intuition says that no observer can be in a mixture of states—yet the cat, it seems from the thought experiment, can be such a mixture. Is the cat required to be an observer, or does its existence in a single well-defined classical state require another external observer? Each alternative seemed absurd to Einstein, who was impressed by the ability of the thought experiment to highlight these issues. In a letter to Schrödinger dated 1950, he wrote:

薛定谔著名的思想实验提出了这样一个问题: “量子系统何时会停止作为叠加态而成为其中之一? ”(从技术上讲，什么时候实际的量子态不再是非平凡的线性组合状态，而是开始有一个独特的经典描述?)如果猫活下来了，它只记得活着。但是，对 EPR 实验的解释与标准的微观量子力学一致，要求宏观对象，如猫和笔记本电脑，并不总是有唯一的经典描述。这个思想实验说明了这个明显的悖论。我们的直觉告诉我们，任何观察者都不可能处于不同的状态ーー然而，从思想实验来看，猫可能是这样一种混合状态。猫是被要求成为一个观察者，还是它存在于一个明确定义的经典状态需要另一个外部观察者？对爱因斯坦来说，每一种选择都是荒谬的，他对思想实验突出这些问题的能力印象深刻。在1950年写给薛定谔的一封信中，他写道:

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Note that the charge of gunpowder is not mentioned in Schrödinger's setup, which uses a Geiger counter as an amplifier and hydrocyanic poison instead of gunpowder. The gunpowder had been mentioned in Einstein's original suggestion to Schrödinger 15 years before, and Einstein carried it forward to the present discussion.

Note that the charge of gunpowder is not mentioned in Schrödinger's setup, which uses a Geiger counter as an amplifier and hydrocyanic poison instead of gunpowder. The gunpowder had been mentioned in Einstein's original suggestion to Schrödinger 15 years before, and Einstein carried it forward to the present discussion.

请注意，在薛定谔的理论中并没有提到火药的电荷，他用盖革计数器作为放大器，用氢氰酸毒药代替火药。15年前，爱因斯坦在给薛定谔的最初建议中就提到了火药，爱因斯坦把它带到了现在的讨论中。

Interpretations of the experiment

Since Schrödinger's time, other interpretations of quantum mechanics have been proposed that give different answers to the questions posed by Schrödinger's cat of how long superpositions last and when (or whether) they collapse.

Since Schrödinger's time, other interpretations of quantum mechanics have been proposed that give different answers to the questions posed by Schrödinger's cat of how long superpositions last and when (or whether) they collapse.

自从薛定谔的时代以来，其他的量子力学诠释学派已经被提出，对于薛定谔猫提出的叠加态持续多久以及它们何时(或是否)崩溃的问题，他们给出了不同的答案。

Copenhagen interpretation

Main article: Copenhagen interpretation

A commonly held interpretation of quantum mechanics is the Copenhagen interpretation. In the Copenhagen interpretation, a system stops being a superposition of states and becomes either one or the other when an observation takes place. This thought experiment makes apparent the fact that the nature of measurement, or observation, is not well-defined in this interpretation. The experiment can be interpreted to mean that while the box is closed, the system simultaneously exists in a superposition of the states "decayed nucleus/dead cat" and "undecayed nucleus/living cat", and that only when the box is opened and an observation performed does the wave function collapse into one of the two states.

A commonly held interpretation of quantum mechanics is the Copenhagen interpretation. In the Copenhagen interpretation, a system stops being a superposition of states and becomes either one or the other when an observation takes place. This thought experiment makes apparent the fact that the nature of measurement, or observation, is not well-defined in this interpretation. The experiment can be interpreted to mean that while the box is closed, the system simultaneously exists in a superposition of the states "decayed nucleus/dead cat" and "undecayed nucleus/living cat", and that only when the box is opened and an observation performed does the wave function collapse into one of the two states.

对量子力学的一个普遍的解释是哥本哈根诠释。在哥本哈根诠释中，一个系统不再是态的叠加态，而是在观测发生时成为一个或另一个。这个思想实验表明了一个事实，那就是测量的本质，或者说观察，在这个解释中并没有得到很好的定义。实验可以解释为，当盒子关闭时，系统同时处于“衰变核 / 死猫”和“未衰变核 / 活猫”两种状态的叠加状态，只有当盒子被打开并进行观测时，波函数才坍缩为两种状态之一。

However, one of the main scientists associated with the Copenhagen interpretation, Niels Bohr, never had in mind the observer-induced collapse of the wave function, as he did not regard the wave function as physically real, but a statistical tool; thus, Schrödinger's cat did not pose any riddle to him. The cat would be either dead or alive long before the box is opened by a conscious observer. Analysis of an actual experiment found that measurement alone (for example by a Geiger counter) is sufficient to collapse a quantum wave function before there is any conscious observation of the measurement, although the validity of their design is disputed. (The view that the "observation" is taken when a particle from the nucleus hits the detector can be developed into objective collapse theories. The thought experiment requires an "unconscious observation" by the detector in order for waveform collapse to occur. In contrast, the many worlds approach denies that collapse ever occurs.)

However, one of the main scientists associated with the Copenhagen interpretation, Niels Bohr, never had in mind the observer-induced collapse of the wave function, as he did not regard the wave function as physically real, but a statistical tool; thus, Schrödinger's cat did not pose any riddle to him. The cat would be either dead or alive long before the box is opened by a conscious observer. Analysis of an actual experiment found that measurement alone (for example by a Geiger counter) is sufficient to collapse a quantum wave function before there is any conscious observation of the measurement, although the validity of their design is disputed. (The view that the "observation" is taken when a particle from the nucleus hits the detector can be developed into objective collapse theories. The thought experiment requires an "unconscious observation" by the detector in order for waveform collapse to occur. In contrast, the many worlds approach denies that collapse ever occurs.)

然而，与哥本哈根诠释相关的主要科学家之一 Niels Bohr 从未想过观察者引起的波函数崩溃，因为他并不认为波函数是物理真实的，而是一个统计工具; 因此，薛定谔的猫并没有向他提出任何谜题。早在盒子被有意识的观察者打开之前，猫就已经死了或者还活着。对一个实际实验的分析发现，单靠测量(例如使用盖革计数器)就足以在有意识地观察测量之前使量子波函数崩溃，尽管其设计的有效性受到质疑。(原子核中的粒子撞击探测器时进行“观测”的观点，可以发展为客观塌缩理论。思维实验需要探测器进行“无意识的观察” ，以便发生波形崩溃。相比之下，多世界的方法否认崩溃的发生。)

Many-worlds interpretation and consistent histories

文件:Schroedingers cat film.svg

The quantum-mechanical "Schrödinger's cat" paradox according to the many-worlds interpretation. In this interpretation, every event is a branch point. The cat is both alive and dead—regardless of whether the box is opened—but the "alive" and "dead" cats are in different branches of the universe that are equally real but cannot interact with each other.

The quantum-mechanical "Schrödinger's cat" paradox according to the many-worlds interpretation. In this interpretation, every event is a branch point. The cat is both alive and dead—regardless of whether the box is opened—but the "alive" and "dead" cats are in different branches of the universe that are equally real but cannot interact with each other.

量子力学的“薛定谔猫”悖论，根据多世界诠释。在这种解释中，每个事件都是一个分支点。不管盒子是否打开，猫既是活的也是死的，但是“活的”猫和“死的”猫在宇宙的不同分支中，它们同样真实，但是不能互动。

Main article: Many-worlds interpretation

In 1957, Hugh Everett formulated the many-worlds interpretation of quantum mechanics, which does not single out observation as a special process. In the many-worlds interpretation, both alive and dead states of the cat persist after the box is opened, but are decoherent from each other. In other words, when the box is opened, the observer and the possibly-dead cat split into an observer looking at a box with a dead cat, and an observer looking at a box with a live cat. But since the dead and alive states are decoherent, there is no effective communication or interaction between them.

In 1957, Hugh Everett formulated the many-worlds interpretation of quantum mechanics, which does not single out observation as a special process. In the many-worlds interpretation, both alive and dead states of the cat persist after the box is opened, but are decoherent from each other. In other words, when the box is opened, the observer and the possibly-dead cat split into an observer looking at a box with a dead cat, and an observer looking at a box with a live cat. But since the dead and alive states are decoherent, there is no effective communication or interaction between them.

1957年，Hugh Everett 公式化了多世界诠释的量子力学，并没有把观察作为一个特殊的过程单独挑出来。在多世界诠释，盒子被打开后，猫的死亡状态和活着状态仍然存在，但是它们彼此分离。换句话说，当盒子被打开时，观察者和可能已经死亡的猫分成两个观察者，一个观察者看着一个装着一只死猫的盒子，另一个观察者看着一个装着一只活猫的盒子。但是由于死态和活态是去相干的，它们之间没有有效的交流或互动。

When opening the box, the observer becomes entangled with the cat, so "observer states" corresponding to the cat's being alive and dead are formed; each observer state is entangled or linked with the cat so that the "observation of the cat's state" and the "cat's state" correspond with each other. Quantum decoherence ensures that the different outcomes have no interaction with each other. The same mechanism of quantum decoherence is also important for the interpretation in terms of consistent histories. Only the "dead cat" or the "alive cat" can be a part of a consistent history in this interpretation. Decoherence is generally considered to prevent simultaneous observation of multiple states.

When opening the box, the observer becomes entangled with the cat, so "observer states" corresponding to the cat's being alive and dead are formed; each observer state is entangled or linked with the cat so that the "observation of the cat's state" and the "cat's state" correspond with each other. Quantum decoherence ensures that the different outcomes have no interaction with each other. The same mechanism of quantum decoherence is also important for the interpretation in terms of consistent histories. Only the "dead cat" or the "alive cat" can be a part of a consistent history in this interpretation. Decoherence is generally considered to prevent simultaneous observation of multiple states.

当打开盒子时，观察者会与猫纠缠在一起，因此形成了与猫活着和死去相对应的“观察者状态” ; 每个观察者状态都与猫纠缠或联系在一起，以便“观察猫的状态”与“猫的状态”相对应。量子退相干保证不同的结果之间没有相互作用。量子退相干的相同机制对于一致性历史的解释也很重要。只有“死猫”或“活猫”才能成为这一解释中一贯历史的一部分。消相干通常被认为是为了防止同时观测多个状态。

A variant of the Schrödinger's cat experiment, known as the quantum suicide machine, has been proposed by cosmologist Max Tegmark. It examines the Schrödinger's cat experiment from the point of view of the cat, and argues that by using this approach, one may be able to distinguish between the Copenhagen interpretation and many-worlds.

A variant of the Schrödinger's cat experiment, known as the quantum suicide machine, has been proposed by cosmologist Max Tegmark. It examines the Schrödinger's cat experiment from the point of view of the cat, and argues that by using this approach, one may be able to distinguish between the Copenhagen interpretation and many-worlds.

宇宙学家马克斯 · 泰格马克提出了薛定谔猫实验的一个变体，即量子自杀机。它从猫的角度检验了薛定谔的猫实验，并认为通过使用这种方法，人们或许能够区分哥本哈根诠释和多重世界。

Ensemble interpretation

The ensemble interpretation states that superpositions are nothing but subensembles of a larger statistical ensemble. The state vector would not apply to individual cat experiments, but only to the statistics of many similarly prepared cat experiments. Proponents of this interpretation state that this makes the Schrödinger's cat paradox a trivial matter, or a non-issue.

The ensemble interpretation states that superpositions are nothing but subensembles of a larger statistical ensemble. The state vector would not apply to individual cat experiments, but only to the statistics of many similarly prepared cat experiments. Proponents of this interpretation state that this makes the Schrödinger's cat paradox a trivial matter, or a non-issue.

系综诠释指出，叠加不过是一个更大的系综的子集合。状态向量不适用于单个的猫实验，而只适用于许多类似准备的猫实验的统计数据。支持这种解释的人声称，这使得薛定谔猫悖论成为一个微不足道的问题，或者说是一个无关紧要的问题。

This interpretation serves to discard the idea that a single physical system in quantum mechanics has a mathematical description that corresponds to it in any way.

This interpretation serves to discard the idea that a single physical system in quantum mechanics has a mathematical description that corresponds to it in any way.

这种解释抛弃了量子力学中的一个单一物理系统有一个数学描述来以任何方式对应它的观点。

Relational interpretation

The relational interpretation makes no fundamental distinction between the human experimenter, the cat, or the apparatus, or between animate and inanimate systems; all are quantum systems governed by the same rules of wavefunction evolution, and all may be considered "observers". But the relational interpretation allows that different observers can give different accounts of the same series of events, depending on the information they have about the system. The cat can be considered an observer of the apparatus; meanwhile, the experimenter can be considered another observer of the system in the box (the cat plus the apparatus). Before the box is opened, the cat, by nature of its being alive or dead, has information about the state of the apparatus (the atom has either decayed or not decayed); but the experimenter does not have information about the state of the box contents. In this way, the two observers simultaneously have different accounts of the situation: To the cat, the wavefunction of the apparatus has appeared to "collapse"; to the experimenter, the contents of the box appear to be in superposition. Not until the box is opened, and both observers have the same information about what happened, do both system states appear to "collapse" into the same definite result, a cat that is either alive or dead.

The relational interpretation makes no fundamental distinction between the human experimenter, the cat, or the apparatus, or between animate and inanimate systems; all are quantum systems governed by the same rules of wavefunction evolution, and all may be considered "observers". But the relational interpretation allows that different observers can give different accounts of the same series of events, depending on the information they have about the system. The cat can be considered an observer of the apparatus; meanwhile, the experimenter can be considered another observer of the system in the box (the cat plus the apparatus). Before the box is opened, the cat, by nature of its being alive or dead, has information about the state of the apparatus (the atom has either decayed or not decayed); but the experimenter does not have information about the state of the box contents. In this way, the two observers simultaneously have different accounts of the situation: To the cat, the wavefunction of the apparatus has appeared to "collapse"; to the experimenter, the contents of the box appear to be in superposition. Not until the box is opened, and both observers have the same information about what happened, do both system states appear to "collapse" into the same definite result, a cat that is either alive or dead.

关系的解释并没有从根本上区分人类实验者、猫或仪器，或者有生命的和无生命的系统; 所有这些都是受同样的波函数进化规则支配的量子系统，所有这些都可以被认为是“观察者”。但是关系解释允许不同的观察者根据他们所掌握的关于系统的信息，对同一系列事件给出不同的解释。猫可以被认为是仪器的观察者; 同时，实验者可以被认为是盒子里系统的另一个观察者(猫和仪器)。在盒子被打开之前，猫，由于其生存或死亡的性质，有关于设备状态的信息(原子要么衰变了，要么没有衰变) ; 但是实验人员没有关于盒子内容状态的信息。这样，两个观察者同时对这种情况有不同的解释: 对猫来说，仪器的波函数似乎是“塌缩”的; 对实验者来说，盒子里的东西似乎是叠加的。直到盒子被打开，并且两个观察者对所发生的事情有了相同的信息，两个系统状态才似乎“崩溃”成为同一个确定的结果，一只猫不是活着就是死了。

Transactional interpretation

In the transactional interpretation the apparatus emits an advanced wave backward in time, which combined with the wave that the source emits forward in time, forms a standing wave. The waves are seen as physically real, and the apparatus is considered an "observer". In the transactional interpretation, the collapse of the wavefunction is "atemporal" and occurs along the whole transaction between the source and the apparatus. The cat is never in superposition. Rather the cat is only in one state at any particular time, regardless of when the human experimenter looks in the box. The transactional interpretation resolves this quantum paradox.

In the transactional interpretation the apparatus emits an advanced wave backward in time, which combined with the wave that the source emits forward in time, forms a standing wave. The waves are seen as physically real, and the apparatus is considered an "observer". In the transactional interpretation, the collapse of the wavefunction is "atemporal" and occurs along the whole transaction between the source and the apparatus. The cat is never in superposition. Rather the cat is only in one state at any particular time, regardless of when the human experimenter looks in the box. The transactional interpretation resolves this quantum paradox.

在交易诠释中，该装置发射一个先进的时间倒流波，与源发射的时间倒流波相结合，形成驻波。这些波被视为物理上的真实，这个装置被认为是一个“观察者”。在交易诠释中，波函数的崩溃是非时间的，并且发生在源和器件之间的整个过程中。这只猫从来不处于重叠状态。不管人类实验者什么时候看盒子，猫在任何特定的时间都只处于一种状态。交易诠释解决了这个量子悖论。

Zeno effects

The Zeno effect is known to cause delays to any changes from the initial state.

The Zeno effect is known to cause delays to any changes from the initial state.

众所周知，芝诺效应会对初始状态的任何更改造成延迟。

On the other hand, the anti-Zeno effect accelerates the changes. For example, if you peek a look into the cat box frequently you may either cause delays to the fateful choice or, conversely, accelerate it. Both the Zeno effect and the anti-Zeno effect are real and known to happen to real atoms. The quantum system being measured must be strongly coupled to the surrounding environment (in this case to the apparatus, the experiment room ... etc.) in order to obtain more accurate information. But while there is no information passed to the outside world, it is considered to be a quasi-measurement, but as soon as the information about the cat's well-being is passed on to the outside world (by peeking into the box) quasi-measurement turns into measurement. Quasi-measurements, like measurements, cause the Zeno effects. Zeno effects teach us that even without peeking into the box, the death of the cat would have been delayed or accelerated anyway due to its environment.

On the other hand, the anti-Zeno effect accelerates the changes. For example, if you peek a look into the cat box frequently you may either cause delays to the fateful choice or, conversely, accelerate it. Both the Zeno effect and the anti-Zeno effect are real and known to happen to real atoms. The quantum system being measured must be strongly coupled to the surrounding environment (in this case to the apparatus, the experiment room ... etc.) in order to obtain more accurate information. But while there is no information passed to the outside world, it is considered to be a quasi-measurement, but as soon as the information about the cat's well-being is passed on to the outside world (by peeking into the box) quasi-measurement turns into measurement. Quasi-measurements, like measurements, cause the Zeno effects. Zeno effects teach us that even without peeking into the box, the death of the cat would have been delayed or accelerated anyway due to its environment.

另一方面，反芝诺效应加速了这种变化。例如，如果您经常查看猫箱，您可能会导致延迟决定性的选择，或者相反，加速它。芝诺效应和反芝诺效应都是真实存在的，并且已知会发生在真实的原子上。被测量的量子系统必须与周围的环境强烈耦合(在这种情况下，与仪器、实验室... ..。等等)为了获得更准确的信息。但是，尽管没有信息传递给外部世界，但它被认为是一种准测量，但是一旦有关猫的健康状况的信息传递给外部世界(通过窥视盒子) ，准测量就变成了测量。类似于测量的准测量会引起芝诺效应。芝诺效应告诉我们，即使不窥视盒子，由于它所处的环境，猫的死亡也会被延迟或加速。

Objective collapse theories

According to objective collapse theories, superpositions are destroyed spontaneously (irrespective of external observation), when some objective physical threshold (of time, mass, temperature, irreversibility, etc.) is reached. Thus, the cat would be expected to have settled into a definite state long before the box is opened. This could loosely be phrased as "the cat observes itself", or "the environment observes the cat".

According to objective collapse theories, superpositions are destroyed spontaneously (irrespective of external observation), when some objective physical threshold (of time, mass, temperature, irreversibility, etc.) is reached. Thus, the cat would be expected to have settled into a definite state long before the box is opened. This could loosely be phrased as "the cat observes itself", or "the environment observes the cat".

根据客观塌缩理论，当某种客观物理阈值(时间、质量、温度、不可逆性等)存在时，叠加自发地被破坏(与外部观测无关)到达。因此，猫应该在盒子打开之前很久就已经进入了一个确定的状态。这可以不严谨地表述为“猫自己观察自己” ，或者“环境观察猫”。

Objective collapse theories require a modification of standard quantum mechanics to allow superpositions to be destroyed by the process of time evolution.

Objective collapse theories require a modification of standard quantum mechanics to allow superpositions to be destroyed by the process of time evolution.

客观的坍塌理论需要修改标准的量子力学，以允许叠加被时间进化的过程所破坏。

Applications and tests

文件:Quantum superposition of states and decoherence.ogv

Schrödinger's cat quantum superposition of states and effect of the environment through decoherence

Schrödinger's cat quantum superposition of states and effect of the environment through decoherence

薛定谔的猫态叠加原理状态和通过退相干的环境效应

The experiment as described is a purely theoretical one, and the machine proposed is not known to have been constructed. However, successful experiments involving similar principles, e.g. superpositions of relatively large (by the standards of quantum physics) objects have been performed. These experiments do not show that a cat-sized object can be superposed, but the known upper limit on "cat states" has been pushed upwards by them. In many cases the state is short-lived, even when cooled to near absolute zero.

The experiment as described is a purely theoretical one, and the machine proposed is not known to have been constructed. However, successful experiments involving similar principles, e.g. superpositions of relatively large (by the standards of quantum physics) objects have been performed. These experiments do not show that a cat-sized object can be superposed, but the known upper limit on "cat states" has been pushed upwards by them. In many cases the state is short-lived, even when cooled to near absolute zero.

所描述的实验是纯理论性的实验，目前尚不清楚所提出的机器是否已经构建好。然而，成功的实验涉及到类似的原理，例如:。相对较大的物体(以量子物理学的标准)的叠加已经完成。这些实验并没有表明一个猫大小的物体可以叠加，但是已知的“猫态”的上限已经被它们推上去了。在许多情况下，即使冷却到接近绝对零度，这种状态也是短暂的。

• A "cat state" has been achieved with photons.

• A beryllium ion has been trapped in a superposed state.

• An experiment involving a superconducting quantum interference device ("SQUID") has been linked to the theme of the thought experiment: "The superposition state does not correspond to a billion electrons flowing one way and a billion others flowing the other way. Superconducting electrons move en masse. All the superconducting electrons in the SQUID flow both ways around the loop at once when they are in the Schrödinger's cat state."

• A piezoelectric "tuning fork" has been constructed, which can be placed into a superposition of vibrating and non vibrating states. The resonator comprises about 10 trillion atoms.

• An experiment involving a flu virus has been proposed.

• An experiment involving a bacterium and an electromechanical oscillator has been proposed.

In quantum computing the phrase "cat state" sometimes refers to the GHZ state, wherein several qubits are in an equal superposition of all being 0 and all being 1; e.g.,

In quantum computing the phrase "cat state" sometimes refers to the GHZ state, wherein several qubits are in an equal superposition of all being 0 and all being 1; e.g.,

在量子计算中，短语“猫态”有时指的是 GHZ 态，其中几个量子位都处于等量叠加态，全部为0，全部为1; 例如,

[math]\displaystyle{ | \psi \rangle = \frac{1}{\sqrt{2}} \bigg( | 00\ldots0 \rangle + |11\ldots1 \rangle \bigg). }[/math]

[math]\displaystyle{ | \psi \rangle = \frac{1}{\sqrt{2}} \bigg( | 00\ldots0 \rangle + |11\ldots1 \rangle \bigg). }[/math]

(| 00 ldots0 rangle + | 11 ldots1 rangle bigg).数学

According to at least one proposal, it may be possible to determine the state of the cat before observing it.

According to at least one proposal, it may be possible to determine the state of the cat before observing it.

根据至少一个方案，在观察猫之前可能确定它的状态。

Extensions

Wigner's friend is a variant on the experiment with two human observers: the first makes an observation on whether a flash of light is seen and then communicates his observation to a second observer. The issue here is, does the wave function "collapse" when the first observer looks at the experiment, or only when the second observer is informed of the first observer's observations?

Wigner's friend is a variant on the experiment with two human observers: the first makes an observation on whether a flash of light is seen and then communicates his observation to a second observer. The issue here is, does the wave function "collapse" when the first observer looks at the experiment, or only when the second observer is informed of the first observer's observations?

维格纳的朋友是两个人类观察者实验的一个变体: 第一个观察者观察一道闪光是否被看到，然后将他的观察结果传达给第二个观察者。这里的问题是，当第一个观察者观察实验时，波函数是“坍缩”的，还是只有当第二个观察者被告知第一个观察者的观察时，波函数才会“坍缩” ？

In another extension, prominent physicists have gone so far as to suggest that astronomers observing dark energy in the universe in 1998 may have "reduced its life expectancy" through a pseudo-Schrödinger's cat scenario, although this is a controversial viewpoint.

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==See also==
另请参阅

• 基本功能 Basis function

• 互补性（物理） Complementarity (physics)

• 共识现实 Consensus reality

• 双缝实验 Double-slit experiment

• Elitzur–Vaidman炸弹测试仪 Elitzur–Vaidman bomb tester

• 半衰期 Half-life

• 海森堡切 Heisenberg cut

• 麦克斯韦的恶魔 Maxwell's Demon

• 测量问题 Measurement problem

• 微黑洞 Micro black hole

• 情态现实主义 Modal realism

• 观察者效应（物理） Observer effect (physics)

• Schroedinbug

• 流行文化中的薛定谔的猫 Schrödinger's cat in popular culture

Further reading

• The EPR paper: Einstein, Albert; Podolsky, Boris; Rosen, Nathan (15 May 1935). "Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?". Physical Review. 47 (10): 777–780. Bibcode:1935PhRv...47..777E. doi:10.1103/PhysRev.47.777.

• Leggett, Tony (August 2000). "New Life for Schrödinger's Cat" (PDF). Physics World. pp. 23–24. Retrieved 28 February 2020. An article on experiments with "cat state" superpositions in superconducting rings, in which the electrons go around the ring in two directions simultaneously.

• Trimmer, John D. (1980). "The Present Situation in Quantum Mechanics: A Translation of Schrödinger's "Cat Paradox" Paper". Proceedings of the American Philosophical Society. 124 (5): 323–338. JSTOR 986572.模板:Registration required

• Yam, Phillip (October 9, 2012). "Bringing Schrödinger's Cat to Life". Scientific American. Retrieved 28 February 2020. A description of investigations of quantum "cat states" and wave function collapse by Serge Haroche and David J. Wineland, for which they won the 2012 Nobel Prize in Physics.

External links

• A spoken word version of this article (created from a revision of the article dated 2013-08-12).

• Schrödinger's Cat from the Information Philosopher.

• Schrödinger's Cat - Sixty Symbols - a video published by the University of Nottingham.

• Schrödinger's Cat - a podcast produced by Sift.

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This page was moved from wikipedia:en:Schrödinger's cat. Its edit history can be viewed at 薛定谔的猫/edithistory