Electrons have no distinguishing features except spin Upon falling into the quantum wonderland while in her living room, Alice finds herself faced with a new reality of existence that seems to baffle her. She is first met with some strange-looking dweller of the new and vastly strange wonderland that she could not make out. She politely introduces herself as Alice, thereby invoking a response from her companion to the effect that it was an electron. Alice also noted that nearby was another similar looking figure to the electron, to which the new acquaintance explained was a different electron.
To Alice, the two electrons looked strikingly alike, down to the umbrella they seemed to have been carrying. Her new friend explains to her that the other electron is actually different; that is, it has a different spin. In essence, the two electrons have absolutely no distinguishing features except for their direction of spin. In the real world, however, things are quite the opposite. Two people, even identical twins, always seem to have distinguishing character traits, which are readily observable.
This latter truth, however, is only implemented to the larger macro-world of classical mechanics, which was espoused by Sir Isaac Newton. 2. Heisenberg’s uncertainty principle Alice’s escapade continues to get more and more bizarre as she notices that her electron companions seemed to always be moving too fast. She in fact asks them to try and slow down a bit so that she can make out how they look like more clearly. As soon as one of her electron friends attempts to reduce his speed, he begins to expand and spread out, filling the entire space around him.
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This makes it even harder for Alice to discern how he really looks like. He then tells her that this is part of the standing rule; that they cannot slow down lest they get too cramped together into the entire space available. This concept is especially abstruse. It is almost as if the electrons increase in number when they slow down, but, in essence, they only occupy the entire space around. This phenomenon is called Heisenberg’s uncertainty principle. It means that it is impossible to ascertain the precise position and the precise location of a sub-atomic particle at the same time.
In essence, Gilmore explicates that Alice cannot see the electron easily when it slows down since its speed is precisely known: it is zero. This is most certainly not the case in the macro-world of Newtonian classical mechanics where we live. Indeed, it is possible to know exactly where someone is and exactly how fast he or she is moving, both at the same time. 3. Pauli’s exclusion principle Another provocative phenomenon Alice encounters in the quantum wonderland is known as Pauli’s exclusion principle.
This principle basically impedes any two subatomic particles to be characterized by the same quantum number. This means that they cannot be in similar quantum states. According to Gilmore, electrons are exactly identical and must therefore abide by the exclusion principle, which was described by Wolfgang Pauli. This meant that Alice’s electron companion could not occupy the same train compartment as its identical counterpart, with a similar spin. Such an elaborate description of the state of affairs at the quantum level is in direct violation of observed phenomena in the macro world of classical mechanics.
In the classical world, two identical entities can indeed share the same compartment. Alice’s electron counterpart states that he cannot be doing the same exact thing as another identical electron. This is not verifiable in the observable world of Newtonian mechanics, where it is possible to have similar entities engaged in the same exact event. 4. Superposition Alice heads out to the Mechanics institute where she gets well acquainted with the concept of superposition. In essence, she learns that subatomic particles such as electrons can be in several different places at the same time.
Classical and Quantum mechanics are the two main fields of mechanics in physics. Classical mechanics came a few hundred years before Quantum mechanics. Subsequently it is less accurate and less reliable then the more recent mechanic field of Quantum mechanics. Despite being outdated, Classical mechanics can still be used for many everyday problems with bigger and slower moving objects. However, ...
She precisely learns that the concept of superposition basically means that an electron is capable of doing all possible things to it. This is verified by the double slit experiment. The experiment yields the phenomenon of interference when electrons are shot out from an electron gun one at a time; they are shot in a beam through an obstacle with two slits and onto a screen. This experiment, and the resulting interference, indicates that each electron passes through the two slits at the same time and essentially interferes with itself.
Similar to the other phenomena that Alice encounters, this one is also in direct violation of common sense judgments of observations in the macro-world. In essence, no observable entity in the real world of classical mechanics is capable of doing all things possible at the same time, let alone be in several different positions at the same time. 5. The Copenhagen interpretation and Schrodinger’s cat Alice proceeds to meet with a series of other unusual characters while in the quantum wonderland.
One of the most intriguing characters she comes across is undoubtedly Schrodinger’s cat. Alice learns that Schrodinger had left a cat behind with some inhabitants of the quantum wonderland which he used as an experiment to test and prove some of the theories espoused within the larger field of quantum mechanics. Schrodinger set up an experiment in which the cat was to be placed inside a box with a flask of poison, a radioactive source and a mechanism that would ensure the poison is released in case if any radiation.
According to Schrodinger’s analysis, the Copenhagen interpretation of quantum mechanics indicates that after some time, the cat is both dead and alive. Nevertheless, when the box is opened, the cat can only be either dead or alive but not both. This abstraction of quantum reality is tormenting to people who live in the macro world of classical mechanics. Things in this world are never in two different states concurrently. Work Cited Gilmore, Robert. Alice in Quantumland: An Allegory of Quantum Physics. New York, NY: Springer-Verlag, 1995. Print.
Tim Berners-Lee graduated from the Queen's College at Oxford University, England, 1976. Whilst there he built his first computer with a soldering iron, TTL gates, an M 6800 processor and an old television. He spent two years with Plessey Telecommunications Ltd (Poole, Dorset, UK) a major UK Telecom equipment manufacturer, working on distributed transaction systems, message relays, and bar code ...