Nov 19, 2018 07:24 PM
Are Quantum Fields Real?
https://www.forbes.com/sites/startswitha...9cc746777a
EXCERPT: The Universe we perceive and view, all around us, isn't representative of what actually exists at a fundamental level. Instead of continuous, solid objects, matter is composed of indivisible quantum particles, held together through invisible forces that act across empty space. Both the particles themselves and the forces can be described by an underlying structure: quantum fields [...] are these quantum fields real? And just what do they tell us? [...]
In physics, a field, in general, describes what some property of the Universe is everywhere in space. It has to have a magnitude: an amount that the field is present. It may or may not have a direction associated with it; some fields do, like electric fields, some don't, like voltage fields. When all we had were classical fields, we stated that the fields must have some kind of source, like particles, which results in the fields existing all throughout space.
In quantum physics, though, this seemingly self-evident fact is no longer true. Whereas classical physics defines quantities like position and momentum as properties of a particle, and those properties would generate a corresponding field, quantum physics treats them differently. Instead of quantities, position and momentum (among other quantities) now become operators, which allow us to derive all the quantum weirdness you've heard so much about.
A quantity like an electron no longer has a well-defined position or momentum, but rather a wavefunction that describes the probability distribution of all possible positions and momenta. You may have heard these words before, but have you ever thought about what that actually means? It means that the electron isn't a particle at all. It's not something you can put your finger on and declare, "the electron is here, moving with this particular speed in this particular direction." You can only state what the overall properties are, on average, of the space in which the electron exists.
[...] So how many fundamental quantum fields are there? Well, that depends on how you look at the theory. In the simplest QFT that describes our reality [...] there are only two quantum fields: the electromagnetic field and the electron field. They interact; they transfer energy and momentum and angular momentum; excitations are created and destroyed. Every excitation that's possible has a reverse excitation that's also possible, which is why this theory implies the existence of positrons (antimatter counterparts of electrons). In addition, photons exist, too, as the particle equivalents of the electromagnetic field.
When we take all the forces that we understand, i.e., not including gravity, and write down the QFT version of them, we arrive at the predictions of the Standard Model. The particles and antiparticles of the Standard Model have now all been directly detected [...] This is where the idea of 12 fermion fields and 12 boson fields come from. These fields are excitations of the underlying theories (the Standard Model) that describe the known Universe in its entirety, and include:
The six (up, down, strange, charm, bottom, top) quarks, and their antiquark counterparts,
The three charged (electron, muon, tau) and three neutral (electron neutrino, muon neutrino, tau neutrino) leptons, and their antimatter counterparts,
The eight gluons (because of the eight possible color combinations),
The two weak (W-and-Z) bosons,
The one electromagnetic (photon) boson,
And the Higgs boson.
[...] Particles, antiparticles, and all sorts of excitations of the fields are constantly being created-and-destroyed. Reality is fundamentally different from our classical picture of a smooth, continuous, well-defined Universe. Although it's true that these quantum fields began as a mathematical construct, they describe our physical, observable reality more accurately than any other theory we've concocted. [...] The Universe may not be an intuitive place, but as far as any physical theory can call itself reflective of reality, QFT has no equal in terms of its power....
MORE (details): https://www.forbes.com/sites/startswitha...9cc746777a
The earth’s mantle may house strange liquids that defy the rules of chemistry as we know them
https://motherboard.vice.com/en_us/artic...arths-core
EXCERPT: Every once in a while, we hear about the horrifying creatures that have been discovered in the deep ocean, which has managed to cement the idea that the deep oceans are the most mysterious, unexplored regions on earth. Let us propose a more mysterious, completely unexplored region: the core and mantle of the earth. According to research published in Nature on Thursday, the mantle may be home to liquids that defy known rules of chemistry because of the extreme temperatures and pressure exposed to materials in the region....
MORE: https://motherboard.vice.com/en_us/artic...arths-core
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https://www.forbes.com/sites/startswitha...9cc746777a
EXCERPT: The Universe we perceive and view, all around us, isn't representative of what actually exists at a fundamental level. Instead of continuous, solid objects, matter is composed of indivisible quantum particles, held together through invisible forces that act across empty space. Both the particles themselves and the forces can be described by an underlying structure: quantum fields [...] are these quantum fields real? And just what do they tell us? [...]
In physics, a field, in general, describes what some property of the Universe is everywhere in space. It has to have a magnitude: an amount that the field is present. It may or may not have a direction associated with it; some fields do, like electric fields, some don't, like voltage fields. When all we had were classical fields, we stated that the fields must have some kind of source, like particles, which results in the fields existing all throughout space.
In quantum physics, though, this seemingly self-evident fact is no longer true. Whereas classical physics defines quantities like position and momentum as properties of a particle, and those properties would generate a corresponding field, quantum physics treats them differently. Instead of quantities, position and momentum (among other quantities) now become operators, which allow us to derive all the quantum weirdness you've heard so much about.
A quantity like an electron no longer has a well-defined position or momentum, but rather a wavefunction that describes the probability distribution of all possible positions and momenta. You may have heard these words before, but have you ever thought about what that actually means? It means that the electron isn't a particle at all. It's not something you can put your finger on and declare, "the electron is here, moving with this particular speed in this particular direction." You can only state what the overall properties are, on average, of the space in which the electron exists.
[...] So how many fundamental quantum fields are there? Well, that depends on how you look at the theory. In the simplest QFT that describes our reality [...] there are only two quantum fields: the electromagnetic field and the electron field. They interact; they transfer energy and momentum and angular momentum; excitations are created and destroyed. Every excitation that's possible has a reverse excitation that's also possible, which is why this theory implies the existence of positrons (antimatter counterparts of electrons). In addition, photons exist, too, as the particle equivalents of the electromagnetic field.
When we take all the forces that we understand, i.e., not including gravity, and write down the QFT version of them, we arrive at the predictions of the Standard Model. The particles and antiparticles of the Standard Model have now all been directly detected [...] This is where the idea of 12 fermion fields and 12 boson fields come from. These fields are excitations of the underlying theories (the Standard Model) that describe the known Universe in its entirety, and include:
The six (up, down, strange, charm, bottom, top) quarks, and their antiquark counterparts,
The three charged (electron, muon, tau) and three neutral (electron neutrino, muon neutrino, tau neutrino) leptons, and their antimatter counterparts,
The eight gluons (because of the eight possible color combinations),
The two weak (W-and-Z) bosons,
The one electromagnetic (photon) boson,
And the Higgs boson.
[...] Particles, antiparticles, and all sorts of excitations of the fields are constantly being created-and-destroyed. Reality is fundamentally different from our classical picture of a smooth, continuous, well-defined Universe. Although it's true that these quantum fields began as a mathematical construct, they describe our physical, observable reality more accurately than any other theory we've concocted. [...] The Universe may not be an intuitive place, but as far as any physical theory can call itself reflective of reality, QFT has no equal in terms of its power....
MORE (details): https://www.forbes.com/sites/startswitha...9cc746777a
The earth’s mantle may house strange liquids that defy the rules of chemistry as we know them
https://motherboard.vice.com/en_us/artic...arths-core
EXCERPT: Every once in a while, we hear about the horrifying creatures that have been discovered in the deep ocean, which has managed to cement the idea that the deep oceans are the most mysterious, unexplored regions on earth. Let us propose a more mysterious, completely unexplored region: the core and mantle of the earth. According to research published in Nature on Thursday, the mantle may be home to liquids that defy known rules of chemistry because of the extreme temperatures and pressure exposed to materials in the region....
MORE: https://motherboard.vice.com/en_us/artic...arths-core
~