The SchrÃÆ'¶dinger cat is a mind experiment, sometimes described as a paradox, designed by the Austrian physicist Erwin SchrÃÆ'¶dinger in 1935. It describes what he sees as a matter of Copenhagen's interpretation of quantum mechanics applied to everyday objects. This scenario presents a cat that may be simultaneously both alive and dead, a country known as quantum superposition, as a result associated with random subatomic events that may or may not occur. Mental experiments are also often displayed in theoretical discussions about the interpretation of quantum mechanics. SchrÃÆ'¶dinger coined the term VerschrÃÆ'¤nkung (winding) in the development of mind experiments.
Video Schrödinger's cat
Origin and motivation
SchrÃÆ'¶dinger intends his mind experiments as a discussion of the EPR article - named after the authors Einstein, Podolsky, and Rosen - in 1935. The EPR article highlights the peculiar nature of quantum superposition, where quantum systems such as atoms or photons can exist as a combination of several states which corresponds to the possibility of different results. The prevailing theory, called the Copenhagen interpretation, says that the quantum system remains in superposition until it interacts with, or is it observed by the outside world. When this happens, the superposition collapses to one or from the definite state of affairs possible. The EPR experiment shows that systems with some particles separated by large distances can be in such superpositions. SchrÃÆ'¶dinger and Einstein exchanged letters on the EPR Einstein article, in which Einstein pointed out that the unstable mes mes mes condition will, after a while, contain superpositions of both bursting and unexploded states.
To illustrate further, SchrÃÆ'¶dinger illustrates how one can, in principle, create superpositions in large-scale systems by making them dependent on quantum particles in superposition. He proposed a scenario with a cat in a locked steel chamber, where a cat lives or dies depending on the state of radioactive atoms, whether it has roted and emitted radiation or not. According to SchrÃÆ'¶dinger, the Copenhagen interpretation implies that the cat remained alive and dead until the state was observed. SchrÃÆ'¶dinger does not want to promote the idea of ​​a dead-alive cat as a serious possibility; instead, he wants an example to illustrate the absurdity of the view of quantum mechanics that exists. However, since the time of SchrÃÆ'¶dinger, another interpretation of the mathematical quantum mechanics has been advanced by physicists, some of whom consider the superposition of "living and dead" cats as real. Intended as a critique of Copenhagen's interpretation (orthodoxy prevailing in 1935), SchrÃÆ'¶dinger's scholarly thought experiments remain a touchstone for modern interpretation of quantum mechanics. Physicists often use the way each interpretation relates to the Schrö¶dinger cat as a way of describing and comparing certain features, strengths, and weaknesses of each interpretation.
Maps Schrödinger's cat
Attempt mind
SchrÃÆ'¶dinger menulis:
Someone can even make pretty ludicrous cases. A cat is placed in a steel chamber, along with the following device (which must be secured from a direct interruption by a cat): on the Geiger counter, there is little radioactive material, so small, that perhaps in the course of one atomic clock decays, but also, similarly, may not exist; If that happens, the counter tube will run out and through the relay release the hammer that destroys the small hydrocyanic acid pumpkin. If a person leaves this whole system for himself for an hour, one would say that the cat is alive if there are no rotting atoms. The first atomic decay will poison it. The psi function of the whole system will state this by including a live and dead cat (forgiving expression) mixed or smeared in equal parts.
It is typical of these cases that the uncertainty originally confined to the atomic domain becomes transformed into macroscopic uncertainty, which can then be solved by direct observation. It prevents us from naive acceptance as a legitimate "vague model" to represent reality. In itself, it will not manifest something that is unclear or contradictory. There is a difference between shaky or out-of-focus photos and portraits of clouds and bank fog.
The famous mind experiment SchrÃÆ'¶dinger posed the question, " when did the quantum system cease to exist as a state superposition and become one or the other?" (More technically, when does the actual quantum state cease to be a linear combination of states, each resembling a different classic state, rather than starting to have a unique classic description?) If the cat survives, he remembers only life. But the explanation of EPR experiments consistent with standard microscopic quantum mechanics requires 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 circumstances - but the cat, apparently from a mind experiment, can be such a mixture. Is the cat needed to be an observer, or does its existence in a well-defined classical state require another external observer? Each alternative seemed implausible to Einstein, who was impressed by the ability of mind experiments to highlight the issue. In a letter to Schrüdinger dated 1950, he wrote:
You are the only contemporary physicist, in addition to Laue, who sees that one can not deal with the assumption of reality, if only one is honest. Most of them do not see what kind of risky game they play with reality - reality as something that does not depend on what was established experimentally. However, their interpretation is denied most elegantly by the radioactive atomic system of charge booster gun gun powder in boxes, where the psi function of the system contains cats alive and is blown into bits. No one really doubts that the presence or absence of a cat is something that does not depend on observation.
Note that gunpowder is not mentioned in the SchrÃÆ'¶dinger setting, which uses Geiger counter as a booster and hydrocyanic toxin instead of gunpowder. The gunpowder was mentioned in Einstein's original suggestion to Schrödinger 15 years earlier, and Einstein brought him forward for this discussion.
Interpretation of experiment
Since SchrÃÆ'¶dinger time, another interpretation of quantum mechanics has been proposed which gives different answers to questions posed by SchrÃÆ'¶dinger cats about how long the last superposition and when (or did ) they collapsed.
Copenhagen interpretation
The usual interpretation of quantum mechanics is the Copenhagen interpretation. In Copenhagen's interpretation, a system ceases to be a superposition of states and becomes one or the other when an observation takes place. This mind experiment makes clear the fact that the nature of measurement, or observation, is not well defined in this interpretation. Experiments can be interpreted that when the box is closed, the system is simultaneously present in the state superposition of "nucleus/dead cat" and "nucleus/live cat", and only when the box is opened and observations made whether the wave function collapses into one of two states.
However, one of the main scientists associated with the Copenhagen interpretation, Niels Bohr, never thought of the falling observer of the wave function, so the SchrÃÆ'¶dinger cat did not raise him. The cat will either die or live long before the box is opened by conscious observers. Analysis of the actual experiment found that only measurements (eg by Geiger enumerators) are sufficient to undermine quantum wave functions before any conscious observation of measurements, although design validity is debatable. The view that "observation" is taken when particles from the core touch the detector can be developed into a theory of objective collapse. Mind experiments require "unconscious observation" by the detector in order for the collapse of the waveform to occur. In contrast, many of the world's approaches to deny the collapse have occurred.
Many consistent world and history interpretations
In 1957, Hugh Everett formulated the interpretation of many-world quantum mechanics, which none of the observations as a special process. In the interpretation of many worlds, the living and dying circumstances of the cat remain after the box is opened, but contradict each other. In other words, when the box is opened, the observer and the dead cat may divide into an observer who sees the box with a dead cat, and an observer who sees the box with a live cat. But because the circumstances of death and life are not coherent, there is no effective communication or interaction between them.
When opening the box, the observer becomes entangled with the cat, so the "observer state" associated with the cat is alive and dead formed; every observer state is entangled or linked to a cat so that "cat observations" and "cat states" coincide with each other. Dynamic quantum conception ensures that different results have no interaction with each other. The same quantum decoherence mechanism is also important for consistent historical interpretation. Only "dead cats" or "live cats" can be part of a consistent history in this interpretation.
Roger Penrose mengkritik ini:
I want to emphasize that, as they are, this is far from the paradox resolution of cats. Because it does not exist in the formalism of quantum mechanics that demands that the state of consciousness can not involve the simultaneous perception of a living and dead cat.
However, the mainstream view (without having to support many worlds) is that decoherence is a mechanism that prohibits such simultaneous perception.
The trial variant of the SchrÃÆ'¶dinger cat, known as the quantum suicide machine, has been proposed by cosmologist Max Tegmark. This tested the Schrödinger cat experiment from a cat's point of view, and argued that by using this approach, one might be able to distinguish between Copenhagen and many world interpretations.
Ensemble interpretation
The ensemble's interpretation states that superposition is merely a sub-element of a larger statistical ensemble. The status vectors will not apply to individual cat experiments, but only for statistics from many similarly prepared cat experiments. Proponents of this interpretation state that this makes the paradox of the Schrödinger cat a trivial matter, or no problem.
This interpretation serves to discard the idea that a single physical system in quantum mechanics has a mathematical description corresponding to it in any way.
Relational interpretation
Relational interpretation does not make a fundamental difference between human experiments, cats, or equipment, or between living and dying systems; all quantum systems are governed by the rules of evolution of the same wave of functions, and all can be regarded as "observers". But relational interpretations allow different observers to assign different accounts to the same set of events, depending on the information they have about the system. Cats can be considered as observers of the apparatus; In the meantime, experiments may be considered other observers of the system in the box (cats plus equipment). Before the box is opened, the cat, due to its life or death, has information about the state of the equipment (the atom has decayed or does not rot); but the experiment has no information about the state of the contents of the box. In this way, the two observers simultaneously have different situations: For the cat, the wave function of the device seems to "collapse"; in the experiment, the contents of the box appear to be in the superposition. Not until the box is opened, and both observers have the same information about what's going on, whether the two system statuses appear to be "collapsed" â € <â €
In transactional interpretation, equipment emits forward waves in time, which are combined with waves emitted by forward sources, forming standing waves. The waves are seen physically real, and the apparatus is considered an "observer". In transactional interpretation, the collapse of the wave function is "temporal" and occurs throughout all transactions between source and equipment. Cats are never in a superposition position. Instead the cat is only in one state at a certain time, regardless of when human experiments are seen in the box. Transactional interpretation solves this quantum paradox.
Zeno effect
The Zeno effect is known to cause delays for any change from the initial state.
On the other hand, the anti-Zeno effect accelerates the change. For example, if you take a peek into your frequent cat box you might cause a delay on a choice that determines or, conversely, speeds it up. The Zeno effect and the anti-Zeno effect are real and known to occur on real atoms. The quantum system being measured must be firmly attached to the surrounding environment (in this case for equipment, experimental rooms... etc) to obtain more accurate information. But while no information is passed to the outside world, it is considered quasi-measurement, but as soon as the information about the welfare of the cat is passed on to the outside world (by peering into the box) the quasi measurement changes into size. Quasi measurement, such as measurement, causes the Zeno effect. The Zeno effect teaches us that without even peering into the box, the cat's death will be delayed or accelerated due to its environment.
The theory of goal collapse
According to the theory of goal collapse, superposition is destroyed spontaneously (apart from external observations), when some objective physical thresholds (time, mass, temperature, irreversibility, etc.) are achieved. Thus, the cat will be expected to go into a definite state long before the box is opened. This can be expressed freely as "the cat observes itself," or "the cat's observing environment."
The theory of goal collapse requires the modification of standard quantum mechanics to allow superposition to be destroyed by the process of time evolution.
Apps and tests
The experiments as described are purely theoretical, and the proposed machine is not known to have been constructed. Successful experiments, though, involve similar principles, e.g. the superposition of relatively large objects (based on quantum physics standards) has been done. This experiment does not indicate that cat-sized objects can be supplied, but the known upper limit on "cat states" has been pushed upward by them. In many cases the country is short-lived, even when cooled to near absolute zero.
- "Cat status" has been achieved with photons.
- The beryllium ion has been caught in a superposition state.
- An experiment involving a superconducting quantum interference device ("SQUID") has been linked to the mind experiment theme: "The superposition state is unrelated to one billion electrons flowing in one direction and another billion oscillating in the other direction." Superconducting electrons move in mass All the superconducting electrons in the Squid flow flow toward the loop at once when they are in a Schrödinger cat condition. "
- A piezoelectric "piezoelectric fork" has been made, which can be placed into the superposition of vibrating and non-vibrating state. The resonator consists of about 10 trillion atoms.
- Experiments involving the flu virus have been proposed.
- Experiments involving bacteria and electromechanical oscillators have been proposed.
Dalam komputasi kuantum, frasa "negara kucing" sering mengacu pada belitan khusus qubit di mana qubit berada dalam superposisi yang sama dari semua yang 0 dan semuanya adalah 1; misalnya.,
Ekstensi
Wigner's friend is a variant of the experiment with two human observers: the first makes an observation on whether flashes of light are seen and then communicates his observations to the second observer. The problem here is, does the wave function "collapse" when the first observer sees the experiment, or only when the second observer is informed of the observer's first observation?
In other extensions, prominent physicists have stated that astronomers who observed dark energy in the universe in 1998 may have "reduced their life expectancy" through the pseudo-SchrÃÆ'¶dinger cat scenario, although this is a controversial point of view.
See also
References
External links
- Erwin SchrÃÆ'¶dinger (1935) Present Situation in Quantum Mechanics (SchrÃÆ'¶dinger, Erwin (citation needed) 3-part translation ("1935)." Die gegenwÃÆ'¤rtige Situation in der Quantenmechanik (Current situation in quantum mechanics) ". Naturwissenschaften . 23 (48): 823807-828812 Bibcode: 1935NW.. 23.807S Doi: 10.1007/BF014918914. Ã, and pp.Ã, 823-828, 844-849) Cat paper SchrÃÆ'¶dinger
- Einstein, A.; Podolsky, B.; Rosen, N. (May 15, 1935). "Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?". Physical Review . 47 (10): 777-780. Code Bib: 1935PhRv... 47..777E. doi: 10.1103/PhysRev.47.777. Ã, EPR Paper
- Phillip Yam (October 10, 2012) Bringing SchrÃÆ'¶dinger Cat to Life , Scientific American. Describing quantum investigations "cat states" and the collapse of wave functions by Serge Haroche and David J. Wineland who won the 2012 Nobel Prize in Physics
- Tony Leggett (August 2000) New Life for Schrödinger Cat , World of Physics, pages 23-24. An article about experimenting with the superposition of "cat state" in a superconducting ring, in which the electrons surround the ring in two directions simultaneously.
- Information Philosopher about the SchrÃÆ'¶dinger cat More diagrams and explanations of information creation.
- Poliakoff, Martyn (2009). "SchrÃÆ'¶dinger's Cat". Sixty Symbols . Brady Haran for the University of Nottingham.
- The SchrÃÆ'¶dinger cat in audio produced by Sift
Source of the article : Wikipedia
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