What do we mean by minus energy ?

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Discussion Overview

The discussion revolves around the concept of "minus energy" in physics, particularly in the context of classical and quantum mechanics. Participants explore the implications of negative energy states, their definitions, and their relevance to particle behavior and potential energy.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions the meaning of "minus energy," suggesting that energy should not be treated like charge, which can be negative.
  • Another participant asserts that all particles in quantum mechanics (QM) have positive energy.
  • A participant notes that the definition of potential energy is crucial to understanding negative energy.
  • It is mentioned that energy is often considered relative to a defined zero energy state, and that discussions typically focus on energy differences.
  • Some participants indicate that negative energy states are associated with bounded states, while positive energy states relate to unbounded states.
  • A participant shares an anecdote about a teacher explaining that if the energy between an electron and a proton is considered zero before gravitational attraction, the electron would lose energy, resulting in a negative energy state, as seen in Bohr's equation.
  • There is uncertainty about the implications of these negative energy states and their significance.

Areas of Agreement / Disagreement

Participants express differing views on the nature of negative energy, with some asserting that all particles have positive energy while others discuss the conditions under which negative energy states arise. The discussion remains unresolved regarding the implications and interpretations of negative energy.

Contextual Notes

The discussion highlights the dependence on definitions of energy states and the relative nature of energy measurements. There are unresolved questions about the implications of negative energy states and their physical significance.

blue bloom
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what do we mean by"minus" energy ??

in the classic physics the minus energy express the gain or loss of the particle ..but when we substitute in the quantum theory lows ,the electron has a minus energy ..I think the energy is not like the charge to be minus ..& I can not also imagine any particle even a small one have a minus energy ..!
 
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Right, all particles in QM have plus energy.
 


It just depends on how you define potential energy...
 


The energy is taken relative to some state (which is defined to have zero energy -- this sometimes happens implicitly). The reason is that in any particular process you only talk about energy differences anyway.

On top of this: usually the negative energy states refer to bounded states, while positive energy states refer to unbounded states.
 


xepma said:
On top of this: usually the negative energy states refer to bounded states, while positive energy states refer to unbounded states.

Exactly.

Bob_for_short said:
Right, all particles in QM have plus energy.

No, xepma has it right.
 


xepma said:
On top of this: usually the negative energy states refer to bounded states, while positive energy states refer to unbounded states.

I think this is the logistic reply ..
I asked a teacher about this ,he told me that if we considered the energy between the electron & the proton equal zero before gravitation ,then the attraction would lead to lose energy & that make the energy of electron always minus (we find that in Bohr's equation)
but I still don't know what are the results of these sign??
 

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