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Negative energy 
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#1
Aug611, 02:57 AM

P: 253

can a matter have negative energy?
or more appropriately what makes some energy as negative? 


#2
Aug611, 03:56 AM

P: 174

It just depends on what your reference point is. For example, as it is convention to have gravitational potential energy at an infinite distance away to be 0 joules, our calculations show GPE to be negative.



#3
Aug611, 08:57 AM

P: 253

i am not certain on that 


#4
Aug611, 09:14 AM

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P: 29,238

Negative energy
One can easily see that, for example, in attractive energies (example: gravitational potential), it is DEFINED that zero is at infinity, and that the gravitational potential well is defined as being negative! The same can be said about the potential that an electron has in an atom (look at the potential energy term in the Schrodinger equation). So you need to learn a bit more of what we mean by negative energy, and why it is rather arbitrary in some sense. Zz. 


#5
Aug611, 10:10 AM

Sci Advisor
Thanks
P: 4,160

The statement you made, "anything that has positive mass must have positive energy" is known as the Positive Energy Theorem or Positive Mass Conjecture, and has been proved under rather general assumptions. See the Wikipedia article http://en.wikipedia.org/wiki/Positive_energy_theorem, or google Positive Energy Theorem and you will find many references to it. 


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