What exaclty is energy on a quantum level?

In summary: However, the energy of a quantum system is not a well-defined quantity. Whenever you measure it, you get a random value, which is one of possible eigenvalues of the operator H. In most cases, energy is measured in order to determine the probability of outcomes of other measurements.In summary, energy on a quantum level is a concept that is essential in understanding the behavior of systems in quantum mechanics. It is defined as the expectation value of the energy operator and is crucial in calculating the outcomes of experiments. However, unlike in classical mechanics, the energy of a quantum system is not a well-defined quantity and can only be measured probabilistically.
  • #1
zeromodz
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I know if energy just suddenly appears in a vacuum it will become radiation in some random form of frequency/wavelength, but what exactly is it on a quantum level? Possibly particle fluctuations of some sort of "energon" (made it up myself). What do you think?
 
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  • #2
zeromodz said:
made it up myself
You're the one making it up. So what is the energy on a quantum level?

In our universe, energy can't just 'appear' in a vacuum. Not would energy become random radiation.
 
  • #3
There is no principal difference between energy in classical and quantum physics. It is just a useful concept which helps physicists to calculate outcomes of experiments. Practically, however, it looks quite different in the 2 cases.

Classically, the energy of a system is defined as the amount of work done by forces to bring it to its current state. Such definition is not very useful in quantum mechanics, because notions like force or trajectory don't make much sense there. Actually, energy is a concept which proved to be extremely useful in quantum mechanics. But one still has to be careful to make the quantum definition agree with the classical one when the quantum effects are negligible. That is, if you push a trolley on 1 meter applying a force 1 Newton, then even if you calculate the outcome using time-dependent perturbation theory of the Schroedinger equation, you must get that the energy of the trolley increases by 1 Joule.

In QM, the energy is essential mostly because the energy operator H (hamiltonian) governs the time-evolution of any system through the Schroedinger equation. Energy can then be defined as the expectation value of H.
 

1. What is energy on a quantum level?

Energy on a quantum level refers to the energy associated with the smallest indivisible units of matter, such as atoms and subatomic particles. This energy is governed by the principles of quantum mechanics, which describes the behavior of particles at a subatomic level.

2. How is energy on a quantum level different from classical energy?

Classical energy is described by classical mechanics, which follows Newton's laws of motion and assumes that energy is continuous and can take on any value. In contrast, quantum energy is discrete and can only exist in specific, quantized levels.

3. What is the relationship between energy and quantum particles?

Quantum particles, such as electrons, photons, and quarks, have inherent energy due to their mass and motion. This energy is quantized and can only exist in certain levels, which determines the particle's behavior and interactions with other particles.

4. How is energy measured on a quantum level?

Energy on a quantum level is measured using units such as electronvolts (eV) or joules (J). These units represent the amount of energy required to move an electron across a potential difference of 1 volt or the energy needed to perform work.

5. What is the significance of understanding energy on a quantum level?

Understanding energy on a quantum level is crucial for many modern technologies, such as transistors, lasers, and solar cells. It also helps scientists better understand the fundamental properties of matter and the behavior of particles in the universe.

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