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Author Topic: how do quantum physics point particles interact  (Read 1798 times)

Offline mxplxxx

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how do quantum physics point particles interact
« on: 28/05/2015 04:18:41 »
if, as quantum physics postulates, particles are incredibly tiny points, how does anything manage to interact?


 

Offline PmbPhy

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Re: how do quantum physics point particles interact
« Reply #1 on: 28/05/2015 05:11:02 »
Quote from: mxplxxx
if, as quantum physics postulates, particles are incredibly tiny points, how does anything manage to interact?
First one has to use quantum mechanics rather than Newtonian mechanics to understand this. In quantum mechanics particles interact by the Coulomb force to create atoms which are not particles but have a finite size. When a large number of them bond together to form a solid you have matter as you know it.
 

Offline evan_au

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Re: how do quantum physics point particles interact
« Reply #2 on: 28/05/2015 12:39:05 »
Quote from: mxplxxx
particles are incredibly tiny points
Some subatomic particles have a fairly definite physical size, like protons & neutrons. They pack together fairly tightly in a nucleus. However, the electric field of a proton extends far beyond the physical size of the proton, allowing interactions with charged particles over a wider area.

Some subatomic particles have a somewhat indefinite size, like electrons and photons. All you can say is probably where they are.
  • If you want higher resolution on your electron microscope, you use a higher accelerating voltage, which results in a higher energy for the electrons and smaller wavelength.
  • If you want to project smaller features onto your microchip, you use light of a higher frequency, which results in a higher energy for the photons and smaller wavelength. 

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how does anything manage to interact?
Perhaps you have heard the saying about a poor marksman: "He couldn't hit the side of a barn"?

Physicists measure the probability that a particle will hit a target in terms of "barns"; it is approximately the cross-section of a Uranium nucleus.

If you have enough particles packed close enough together, passing each other often enough, you eventually get some collisions.
  • Particles like protons which respond to the electric force and the strong nuclear force interact easily.
  • Particles like the ghostly neutrino respond mostly to the weak nuclear force and are very hard to detect
  • The mysterious Dark Matter is thought to respond mostly to gravity, which would make subatomic particles of low mass even harder to detect. 

The LHC produces bunches of 1011 protons squeezed into a beam which is about 16 micrometers wide; they arrange head-on collisions of such bunches about 40 million times per second. The LHC achieves millions of interactions per second.
 

Offline mxplxxx

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Re: how do quantum physics point particles interact
« Reply #3 on: 28/05/2015 14:04:44 »
Thx. I also found a good article at http://www.fnal.gov/pub/today/archive/archive_2013/today13-02-15_NutshellReadMore.html.

Further to particle interactions, I think the Cosmos can be simulated via a UML (Unified Modelling Language) Statechart. This a computer construct base on an abstract state machine (see the statechart of a hydrogen atom in my previous post http://www.thenakedscientists.com/forum/index.php?topic=57348.0#quickreply. In this scenario, Fermions are states and Bosons are events. Events don't/can't change state and point particles (bosons) would seem to be the cosmological equivalent of events. They can't actually hit anything or interact with each other being of zero dimension.  States need to trap events and thus fermions which are the cosmological equivalent of states (sort of, they are actually state-times, closely related to space-time). Fermions likely detect events/bosons as the latter pass through the fermion's associated field (more likely close to nucleus, less likely close to boundary of field). A Fermion that detects a boson (event) in its field then changes state depending on its current state, the nature of the event/boson and the cosmological laws governing the particular state/event interaction.


 
« Last Edit: 28/05/2015 14:53:53 by mxplxxx »
 

Offline PmbPhy

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Re: how do quantum physics point particles interact
« Reply #4 on: 28/05/2015 16:39:59 »
Quote from: evan_au
Some subatomic particles have a somewhat indefinite size, like electrons and photons. All you can say is probably where they are.
That's true for all particles, not just point/elementary particles.
 

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Re: how do quantum physics point particles interact
« Reply #4 on: 28/05/2015 16:39:59 »

 

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