Pointlike particles and the emergence of classicality

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Discussion Overview

The discussion revolves around the interpretation of the emergence of classicality from quantum mechanics, particularly focusing on the nature of pointlike particles, mass, and the implications of quantum phenomena such as wave function collapse and tunneling. It explores conceptual challenges related to how a classical world, where certain physical interactions are experienced, arises from quantum descriptions.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about how a classical world can exist when quantum mechanics describes particles as dimensionless and energy-based, questioning the processes like wave function collapse that lead to this classical experience.
  • Another participant suggests that the forces between particles are significant, indicating that trying to push through a wall involves moving these force configurations to a higher energy state, which requires considerable effort.
  • A participant proposes that mass might be perceived as an illusion, suggesting it could be analogous to pointlike charges interacting with their environment through forces.
  • In response, another participant argues that mass is not an illusion but can be classified similarly to charge in gravity, emphasizing the always attractive nature of gravitational force.
  • One participant explains that tunneling is improbable for a single electron and that for a person to walk through a wall, all particles in their body would need to tunnel simultaneously, which they claim has a probability of zero.
  • Another participant discusses how classical behavior emerges from quantum mechanics, noting that certain states become more probable at larger actions, leading to the identification of "classical paths" through the path integral formulation of quantum mechanics.

Areas of Agreement / Disagreement

Participants express differing views on the nature of mass and its relation to quantum mechanics, with some suggesting it may be an illusion and others asserting its reality. The discussion remains unresolved regarding the interpretation of classicality and the implications of quantum phenomena.

Contextual Notes

The discussion touches on complex concepts such as wave function collapse, tunneling, and the path integral formulation, which may involve assumptions or definitions that are not fully articulated by participants.

DMuitW
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I've got some conceptual problems on how to interpret the emergence of a classical world, in which, i can't walk through walls, by what is in quantum mechanics described as dimensionless energy 'particles' who have manifested themselves out of the collapse of the wave function (by whichever process, decoherence, measuring,...)

Can anyone enlighten me on this subject? thanks
 
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DMuitW said:
I've got some conceptual problems on how to interpret the emergence of a classical world, in which, i can't walk through walls, by what is in quantum mechanics described as dimensionless energy 'particles' who have manifested themselves out of the collapse of the wave function (by whichever process, decoherence, measuring,...)

Can anyone enlighten me on this subject? thanks

The particles have forces acting between them - quite strong forces. When you try to push your hand through the wall you are trying to move these powerful force configurations to a higher energy state. That takes a lot of work!
 
So, actually, mass is just an illusion that we perceive as pointlike charges who interact on their environments through forces?
 
No, mass is not an illusion. It can be sort of classified as a quantity analogous to charge for gravity, except for the always attractive nature of the gravitational force.

Tunneling is improbable for one electron; in order for you to walk through a wall, you'd need to have every single particle in your body spontaneously tunnel through the wall and return to the original configuration. Although this might happen, the probability of its happening is zero.

Essentially, the classical regime appears because certain states are more probable than others, and when we get into large action (as in the [tex]\int_{t_0}^t' L(\dot{q}, q, t) dt[/tex] action) certain paths and actions become more probable. These are the "classical paths" that are returned from quantum mechanics. There's some degree of detail of "deriving" classical mechanics from the path integral formulation of quantum mechanics in any book that discusses path integration.
 

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