A theory of how small particles are formed and act based on the quantum principle (by which energy is emitted in certain packets, or quanta) and the uncertainty principle.
Quantum mechanics Quotes in A Brief History of Time
The A Brief History of Time quotes below are all either spoken by Quantum mechanics or refer to Quantum mechanics. For each quote, you can also see the other terms and themes related to it (each theme is indicated by its own dot and icon, like this one:
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Chapter 8
Quotes
We don’t yet have a complete and consistent theory that combines quantum mechanics and gravity. However, we are fairly certain of some features that such a unified theory should have.
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Quantum mechanics Term Timeline in A Brief History of Time
The timeline below shows where the term Quantum mechanics appears in A Brief History of Time. The colored dots and icons indicate which themes are associated with that appearance.
Chapter 1
Scientists now describe the universe in terms of the general theory of relativity and quantum mechanics —both great achievements of the first half of the 20th century. The first relates to...
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...the ultimate theory becomes hard to justify. Then again, people argued this about relativity and quantum mechanics , which eventually gave us nuclear power and microelectronics. Thus, the search for a theory...
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Chapter 3
...curved, like the surface of the earth. When combining the general theory of relativity with quantum mechanics (as discussed later), space and time can be finite without a boundary. But this doesn't...
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...there was a big bang. However, Hawking himself has since changed his mind, when taking quantum mechanics into account.
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...down at the beginning of the universe. When the universe was squeezed into infinite density, quantum mechanics comes into play. As such, their focus turned from the massive to the miniscule.
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Chapter 4
Heisenberg, Erwin Schrodinger, and Paul Dirac in the 1920s created quantum mechanics based on the uncertainty principle. This theory does not predict definite outcomes, but potential outcomes....
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...electrons could only orbit at specific distances, which would balance it all out. According to quantum mechanics , the electrons would move as waves, and therefore would only form orbits where the...
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Einstein’s general theory of relativity is considered a classical theory because it does not include quantum mechanics . This does not lead to inconsistency, though, as gravitational forces are so weak compared...
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Chapter 5
...the first to propose a theory consistent with both the general theory of relativity and quantum mechanics . He showed mathematically how spin ½ works and predicted that electrons should have partners,...
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...same way as our own. Any theory that obeys the general theory of relativity and quantum mechanics must follow the symmetry of CPT. J. W. Cronin and Val Fitch proved the universe...
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...happens in that time, when they become a black hole, that draws general relativity and quantum mechanics together.
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Chapter 6
...light was a particle or a wave, and how gravity would therefore affect it. Under quantum mechanics , scientists know it is both. Gravity will affect light the same way it does...
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Chapter 7
...people up the wrong way, and was the first significant example of general relativity and quantum theory combining. John G. Taylor opposed Hawking when he announced these discoveries. But in the end,...
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...emissions. But is seems when a black hole becomes really small, it will simply disappear. Quantum theory seemed to undermine the idea of singularities, and Hawking’s work turned in that direction in...
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Chapter 8
...collapses back in on itself, or in localized singularities in black holes. But when applying quantum mechanics , it is clear that black holes re-emit mass and energy into the universe, eventually...
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...would also account for why there is so much matter in the universe. According to quantum theory , particles can be created by energy, which raises the question of where the energy...
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...becomes so strong that we need to return to the quantum level, and use a quantum theory of gravity.
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There is no consistent theory that combines quantum theory and gravity. If there were, it should involve Feynmann’s sum over histories proposal, which states...
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Another feature of the unified theory of quantum mechanics and general relativity is that gravity is represented in a curved space-time. Applying the sum...
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...to be so powerful at these points that it had to be considered on the quantum theory scale. Singularities will only appear as such in real time, but one could equally say...
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Chapter 9
To unify gravity with quantum mechanics , one must apply imaginary time. Imaginary time is no different from the dimensions of...
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...way from the cosmological arrow, but that is not what we observe. One requires a quantum theory of gravity to know how it all began, rather than guess.
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Chapter 10
Quantum theory allows a negative energy balance in certain areas as long as the universe’s overall balance...
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Chapter 11
...about nuclear science at the time, but also because of his own refusal to accept quantum theory despite his own input into its creation. The uncertainty principle, on which quantum theory is...
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...into GUTs is that it does not take into account the uncertainty principle that defines quantum mechanics .
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Chapter 12
Today, Laplace’s approach is defunct because of the uncertainty principle of quantum mechanics , which introduces a minimum level of randomness. Quantum theory gives particles less well-defined positions...
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Introducing quantum mechanics , however, leads to ideas of a finite, four-dimensional space with no boundaries. This could...
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