Fields don’t expand-it’s spacetime that expands. However, in a curved spacetime, relative velocity-like any 4-vector-can’t be globally defined. That’s why the ``speed of expansion" of spacetime doesn’t make sense.

Incidentally, in curved spacetime, the vacuum state of quantum fields isn’t globally defined, either.

There are other ways to ``measure'' spacetime expansion and its effects on quantum fields, defined on such a spacetime. Cf. for instance, Article Quantum fields in curved spacetime

The massless quantum field in QFT is a false proposition.

The massless quantum field in QFT is a pseudo concept with chaotic logic.

The definition of quality must come from the material as the precondition,

The definition of matter must come from the object as a precondition,

When physical theory was not born, we could not use physical theory to define objects and substances.

I used (logic+reality) to define and prove that as long as there are particles in the universe,

Particles must have mass; Understand that as long as there is matter in the universe, there must be mass.

It proves that quantum must be matter (or property of matter), so quantum must have mass.

There is no such concept as "massless quantum field".

The universe has no virtual particles, because the definition of particles is based on the "real concept".

So there is no virtual quantum in the universe.

We get: (no mass)=(zero quantum field), (zero quantum field)=(absolute vacuum).

It can be proved that the universe is infinite (the universe is not produced by the Big Bang of Singularities, the universe has always existed), and the mechanical principle also proves that matter is infinite.

No matter how the universe horizon expands, there will always be new substances found in the new horizon, because matter is infinite.

I do not understand the question.

Just want to know, according to quantum field theory (QFT), does a massless quantum field mean that the photon field expands with the cosmological expansion of space due to dark energy?

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There are two pseudo concepts: dark energy and cosmic expansion.

Because we can prove that the universe is infinite, we can prove that the infinite universe cannot expand by using the definition of {infinite, expansion}.

Note: Limited earth can expand, not belong to cosmic expansion. Reason: "The infinite expansion of the universe" is contradictory.

It defines the universe and proves that the universe has only two basic concepts: the smallest particle in motion and the absolute vacuum.

The logical definitions of object, matter, mass and energy are obtained. It proves that there is no dark matter and dark energy in the universe.

In following theory, vacuum space does not expand but the quantum fields expand which gives you the illusion of space expanding. Following para appears under Eq.(9.2) of following article.

Periodic relativity: the theory of gravity in flat space time

https://www.researchgate.net/publication/341999450_Periodic_relativity_the_theory_of_gravity_in_flat_space_time

https://arxiv.org/abs/0707.4539v11

From Eq.(9.2) we can see that the expansion of universe is due to quantum field expanding and not due to the space expanding as in the GR. Dark energy (68.3%) is the energy of quantum field which is not manifest as the particles, or manifest as hard to detect ground state particles. Quantum fields are expanding within the singular motionless fundamental substance of the universe which is infinite in extent, but the quantum fields are not infinite. So the zero point energy of the quantum fields can be restricted to match the cosmological constant as in Eq.(9.2) and this should solve the cosmological constant problem.

Eq.(9.2) relates GR parameters with the wave equation parameters of the quantum gravity theory given below.

https://www.researchgate.net/publication/338621845_Periodic_quantum_gravity_and_cosmology

The presence of the motionless infinite fundamental substance of the universe sets the same initial conditions everywhere including causally disconnected regions of space which explain the cosmological Horizon Problem.

Vikram Zaveri

Interesting theory. Seems more like a homogeneous locally crystallization phase where the "motionless infinite fundamental substance of the universe" as you described it has undergone a simultaneous change in matter-energy phase and less than an inflation of a singularity.

Emmanouil Markoulakis

Singularity of general relativity has a geometrical boundary. Infinite fundamental substance of the universe is also a singularity but without a geometrical boundary because the fundamental substance is non material and hence cannot have a material boundary. The inflation in this theory uses the exponential part of the wave equation itself and the inflation is continuous from the Planck epoch to the present epoch. The theory works with or without the dark energy. Since time is periodic in this theory, there is no specific starting point for the universe. Wherever the fundamental substance begins to move in waves, you get the time period and that could be the local starting point. JWST has discovered large density of galaxies at high redshifts which puts tight constraints on the expansion history of the universe and rule out the major portion of the parameter space of the dark energy models (arXiv:2208.1147)

The simple answer is yes, any quantum field associated with massless particles, like photons or quarks, will expand as space expands.

The reason for this is that all quantum fields follow the changes in space-time. This is why quantum fields are said to be "background dependent," where space-time is the background. This means that when there are curvatures or expansion of space, the quantum fields track those curvatures and expansion. In other words, space-time acts as a background reference for quantum fields.

The only force that we know of that is not background dependent is gravity. And that is one of the reasons why gravity has not yet been characterized as a quantum field.

All of this is based on our current understanding of quantum theory. But it raises questions that have still not been answered, so this might all change as we learn how to solve the quantum gravity paradox.

With all due respect...Electron/positron, proton/neutron, matter/antimatter, quark...or anything inside of atom never been observed yet, how could we are going to judge something that never been observed of seen?

Quantum mechanics with field or standard of atom never been confirmed...so how could anyone make a judgement that never been seen?

You might say. It just prediction, postulation of follow the modeling of atom, but, that is not science.

Science must based on solid evidence, not some prediction.

By the way, Particle means mass, any there is no such massless particle. Massless entity has no volume, no shadow, any mass.

Javad Fardaei asked: How can we judge something that has never been observed or seen?

Yes, this is the nature of quanta, they cannot be observed directly. However, this is not the first time we have faced things that cannot be observed directly.

For example, biologists who wanted to study the lives of apes or other wild animals quickly realized that the behavior of animals changes as soon as they try to observe them. As a result, they realized that the act of observation actually changes the behavior of the animals making it almost impossible to see them in their natural state without affecting their behavior. This is quite close to what physicists have found with quantum behavior--observation changes their state.

Psychologists also face a similar problem when trying to run experiments to see the natural behavior of people. For example, if they want to find out how the subconscious works and influences the behavior of people, they need to design their experiments so that the subjects are not aware of the true purpose of the experiment, because if they are aware of what is being looked for, they will change their behavior. Also, by putting subjects in an environment that isolates them from their normal lives, this also alters their natural behavior.

On a more personal level, think about a close friend of yours. If you know them well, then you will likely know how they will respond if you tell them a joke or ask them a political question. In fact, however, you only really know how they will respond when you are the one who is asking them that question, and how they will respond when they are with you. This means that you really don't know how they will respond when you are not with them. This shows us that knowing a friend is not objective observation, it is a different kind of knowing that comes from being with them, doing things together, etc.

We may not be able to objectively measure quantum states directly, but we can see the effects of quantum states. We cannot observe those states as outside observers, but we still can see the effects on the observable world, and experiments can be run that show exactly how and when quantum states affect the world. Since these results are consistent and repeatable, it becomes something that we can judge as being real, even though we cannot see these quantum states directly.

Dear Doug Marman

Thank you for feedback, few months ago I had speech in the International Physics Conference in Denmark and April in Intrnl webinar , My speech subject was to Unify applied science to nanotechnology. generally speak of, all scientists, chemist, quantum computing, nanotechnologist, medics...etc. do not see the atom mechanic with charges.

Science is following standard modeling of atom, which it is still a theory. Standard modeling of atom has been stablished without investigation, to my understanding is made up phenomenon, due to collapsing modern physics into quantum perception. yet science is following it for no reason, for same reason everything of atom is unclear, because foundation is wrong.

I'm not trying to change your perception, but to my understanding atom are smallest sentient unit of our universe and it is made of part to study it. , I think in another century science would not see any electron/positron, or separation of proton/neutron,

https://www.academia.edu/77501692/Webenar_April

Space horizon problem is about the difficulty of fine tuning problem in Big Bang model of Universe in explaining the observed homogeneity of casually disconnected regions of space in the absence of a mechanism that sets the same initial conditions every where.

We are not able to explain homogeneity of disconnected regions of space and this difficulty increase more when same thing is to be observed in Universe. Indirectly we say dark energy helps in expansion of photon field and space time itself. But

we are not able to explain the geometry of space, around any event horizon, when a photon like particle passes through such region with the help of existing theories.