How bosons do not violate conservation of energy?

Question

As far as I understand bosons are energy packets which carry forces: e.g. Higgs bosons carry gravity. What I don't understand is, for example if we have an isolated object which constantly releases these energy packets, then after time, it should lose mass or temperature or kinetic energy to cover the energy these packets contain, otherwise it would violate conservation of energy. On the other hand if they are not constantly released, just by interactions, then how do an object know there is an interaction and it should release them? In that case too they are converted into kinetic energy, so the conservation of energy is violated again. What am I missing?

Answer 1

Objects aren't constantly releasing energy packets. But you can imagine objects do carry a field around them. There is indeed energy associated with this field.

For instance a charged object carries an electromagnetic field around. In quantum field theory, interaction through this field can be described by things called Feynman diagrams, and certain lines in these diagrams are called 'virtual photons'. But these virtual photons aren't traveling waves, it is best to think of them as how the electromagnetic field you are hopefully familiar with from classical physics is described in the context of Feynman diagrams.

The field does have energy and contributes to the mass of the particle it surrounds in both classical electromagnetism and quantum field theory. In Feynman diagrams this shows up as a particle emitting and reabsorbing a virtual photon (and more complicated diagrams). But you can't 'lose' a virtual photon, and lose energy.

It is true though that if particle is accelerated by the presence of another particle, it can give off energy in the form of electromagnetic waves, and this shows up in Feynman diagrams as emission of a real (not virtual) photon. This energy is coming from the potential energy between the two particles.

I've been talking about photons and electromagnetic fields, but the same picture applies to less familiar things like the Higgs field (which has nothing to do with gravity, by the way).

Answer 2

There are two definitions of bosons and the first comment refers to "entities" that you can measure based on their Spin Angular Momentum. In as far as we can say, that any quantum scale object is a real thing, these composite objects are real. You can add fermions together to give you a boson, in spin angular momentum terms.

The second class of bosons are actually called "gauge bosons", and rather than trying to compare them as being similar in some way to real bosons, a guage boson is much better thought of as a process, not a particle. It is a totally mathematical description of how, for example, the weak force is transmitted between certain fermion, (objects with half integer spin).

The uncertainty principle comes in to this, as during this process of transferring a force, the classical law of conservation of energy is briefly contravened, but in overall terms, on average, any classical measurement would not detect this momentary breakdown, it's too fast to measure, especially as the mass (energy) of the gauge boson increases.

The word gauge comes into it, through the fact that, to ensure that all observers in the universe agree that an interaction mediated by the weak force has occured, at the same time and place, we tweak the math that describes the process. The standard explanation of this, is that to build a level floor on uneven ground, we have to adjust the height of the underlying supports.

On the other hand if they are not constantly released, just by interactions, then how do an object know there is an interaction and it should release them?

This is a law of nature, in the same way that an electron will change energy levels when it receives momentum from a photon. But, unlike the classical world, it is a probabilistic law, it will almost certainly, but not 100 per cent, occur. The objects "know" about each other because they can be thought of as detecting the field (that they are composed of themselves), that the other object is composed of, and if they get close enough, the exchange process will almost certainly occur.

Mental pictures might help, but they always break down and mislead you, if you push them too far. I feel you are applying classical concepts, to try to understand the quantum scale and the only way around that is to try and follow the math involved, at least as far as you can.

If you read Carroll's "The particle at the end of the universe", or even better, Schaumm's "Deep Down Things", this will give you a good general idea, based on basic math.

I appreciate @octonion remarks on what I suspected was a rickety part of my answer and I put this edit here in case comments are deleted.

I must point out that the picture of conservation of energy being violated momentarily doesn't appear anywhere in the actual physics. This was made up at some point by a popularizer of physics and unfortunately was repeated by others. The places it works to give a good order of magnitude estimate are simply due to unit analysis.

Answer 3

As far as I understand bosons are energy packets which carry forces: e.g. Higgs bosons carry gravity.

Wrong . Higgs bosons of the standard model are particles which interact/couple with the weak interaction, not the gravitational one.

There are four interactions/forces in nature, and three of them are modeled by gauge theories. The strong, the weak, and the electromagnetic within a quantum field theoretical model. The gravitional are effective field theoretical models because there is no definitive quantization of gravity yet. The forces are characterized by the coupling constants in the table.

Within the context of Feynman diagram calculations for crossections and decays, the first order exchanges, i.e. the higher probability diagrams, happen with the so called gauge bosons. These are the photon for electromagnetic interactions, the W and Z bosons( depending on charge conservation in the diagram) are the first order exchanges for the weak interactions, and the gluon for the strong. All are spin 1, the photon and the gluon are massless. The Z and W become massless at the symmetry breaking scale , seen here in the history of the universe as modeled presently.

The Higgs boson is a particle manifestation of the Higgs field the way that the electron is the particle manifestation of the electron field etc for all the particles in the standard model. The expected gauge boson for gravity, once it has been definitively quantized, is supposed to be the graviton.

It is the coupling constants at the vertices which characterize which "force" is taking part in the diagram.

Here are the first order feynman diagrams for weak and electromagnetic contributing to electron electron elastic scattering:

The Z boson as depicted as well as the photon are off mass shell, virtual particles and are place holders for the integral descibing the contribution of the weak and the electromagnetic forces to ee scattering. There are always higher order diagrams in the expansions, and these can be any of the particles in the particle table as long as quantum numbers are conserved.

Momentum and energy conservation laws have to hold for the real particles input and output. So there is no problem with energy momentum conservation. Nothing is "released" within a feynman diagram, it is all mathematics under an integral with strict quantum number conservation within the virtual domain too,but energy and momentum conservation imposed only between input and output real particles.