How do quantum phenomena affect macroscopic phenomena?

  • #1
curiosity1
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How do quantum superposition, indeterminacy, tunnelling, and entanglement affect macroscopic phenomena such as tossing a coin, throwing dice, human thoughts, human emotions, decision-making by humans, the behaviour of other sentient animals, photosynthesis, genetic mutation, the speed of light, gravity, the orbits of stars, planets, moons, the orbits of satellites, mobile phones, computers, magnetism, earthquakes, cyclones, etc.?
 
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That's a pretty wide-ranging list, and for some of those things (human thoughts, emotions and decision making, animal sentience) we don't know the underlying mechanism so don't know whether quantum mechanical effects are involved. For others (speed of light, gravity, planetary and stellar orbits) quantum mechanics is generally irrelevant.

However, the bulk properties of matter (chemistry, density, hardness, melting and boiling points, ...) are ultimately explained by quantum mechanics, although in practice the quantum weirdness (superposition, tunneling, entanglement, indeterminacy) all average out - there is indeterminacy about the exact location of any given iron atom but not about the exact location of the center of mass of a cannonball formed by 10^27 of these quantum-behaving atoms.

Quantum mechanics is essential to just about all modern electronics.

You will get more and more detailed answers if you can be more specific - you've kind of asked for an executive summary of all human knowledge here.
 
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  • #3
Thank you for your reply. I thought quantum indeterminacy applied to electrons instead of entire atoms. Am I incorrect?
 
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curiosity1 said:
I thought quantum indeterminacy applied to electrons instead of entire atoms.
Why would you think that?
 
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  • #5
curiosity1 said:
How do quantum superposition, indeterminacy, tunnelling, and entanglement affect macroscopic phenomena such as tossing a coin, throwing dice, human thoughts, human emotions, decision-making by humans, the behaviour of other sentient animals, photosynthesis, genetic mutation, the speed of light, gravity, the orbits of stars, planets, moons, the orbits of satellites, mobile phones, computers, magnetism, earthquakes, cyclones, etc.?
Macroscopic quantum phenomena that might be of your interest: superconductivity and superfluidity.

Indeterminacy, dice, coin tossing, weather: chaotic systems are very sensitive to initial conditions, if the conditions are decided randomly (or near-radomly) in quantum mechanics, then we can never predict how a chaotic system will evolve after a certain time.

Tunneling: electric wires can get oxidized locally, tunneling allows electrons to tunnel over these defects. If tunneling did not exist, electrical wire would be much more sensitive to any problems. Tunneling also allows for radioactivity and nuclear fusion (see stars below). Human are also said to be able to smell due to tunneling. The nose can be thought as scanning tunneling microscope that can determine specific signatures of molecules (details still under debate).

Photosynthesis: light gets recovered efficiently and it is moved to the reaction centre of chlorophyl molecule. It is believed this is quantum transport. Details are still debated.

Genetic mutation: part of genetic mutations happen due radioactivity and cosmic rays coming from outside Earth.

Magnetism: per the Bohr–Van Leeuwen theorem, magnetism in matter is purely a quantum phenomena. Some animals like bird are said to have "quantum" navigation systems that allows them to determine the magnetic field of Earth.

Mobile phones and computers: these are machines that use a zillion of transistors. The transistor is a quantum phenomena based on electronic band theory. Also some memories use giant magnetoresistance which depends on the electronic spin.

Stars: the temperature of a star can be determined by their luminosity, which is one of the first quantum mechanical effects ever described. We can also know what they are made of from the emission spectrum. A star is also held from gravitational collapse due to nuclear fusion in the core (white dwarfs are even held just by Pauli exclusion principle). Also some stars are made of more exotic matter, like neutron stars that behave like a giant atomic nuclei.

Speed of light: it is in principle not modified or explained by quantum mechanics.

Gravity: we do not have a quantum theory of gravity.

Orbits of astronomical bodies, earthquakes: not much.
 
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  • #6
PeterDonis said:
Why would you think that?
I thought atoms would be too big for quantum indeterminacy. I thought it applied only to electrons. I am not a physicist or even studying physics at university. Please clarify which particles are affected by quantum indeterminacy. Thank you.
 
  • #7
curiosity1 said:
Please clarify which particles are affected by quantum indeterminacy. Thank you.
What do you mean by quantum indeterminancy?
 
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  • #8
curiosity1 said:
I thought atoms would be too big for quantum indeterminacy. I thought it applied only to electrons.
Why would you think that?
 
  • #9
curiosity1 said:
I thought quantum indeterminacy applied to electrons instead of entire atoms. Am I incorrect?
"Quantum indeterminacy" is an unintuitive term, but in modern physics it means that physical events take place in nature that obviously have no determinate cause.
 
  • #10
PeroK said:
Why would you think that?
Because I didn't know any better.
 
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  • #11
curiosity1 said:
Please clarify which particles are affected by quantum indeterminacy.
It's not that simple. "Quantum indeterminacy" is not a binary thing that's either "on" or "off", or applies to some systems but not others. Roughly speaking, the smaller the system is, the larger the effects of quantum indeterminacy are. But that's still a very rough statement; to really understand the role it plays in a particular scenario, you need to look at the details of the scenario.
 
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  • #12
Quantum phenomenons are measured using macroscopic measuring devices so any recorded quantum phenomenon has been effected the macro scale some how. But it an interesting question to ask what could create positive feedback and have big effect on macro world
 
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