[geordief (OP)]

Does "relative motion" only apply to classical objects or does the concept apply also in quantum mechanics?

Suppose we have a classical object (or an aggregation of  "quantum objects"-I understand they are modelled as excitations in a field) does anything  external have to happen  to cause these constituent parts to move in relation to each other  or is their initial configuration  enough to set this process in motion ?(no pun intended)

If no external intervention is required is there a correlation between the energetic content of the initial configuration and the resulting relative speeds of the constituent parts?

[yor_on]

Some ways.

That is macroscopic
It's not macroscopic

Quantum mechanically everything is expected to 'vibrate'
But if you have a vibration you also need a arrow of time.

A vibration can never be a 'uniform motion' though
It 'vibrates' right?

And that's an acceleration

[yor_on]

Ok, sorry

Quantum mechanically it's not a vibration
It's an uncertainty

still, if something 'vibrate' it will be a acceleration

[yor_on]

I don't know geordief . When I discuss 'relative motion' I do it macroscopically.
Scaling it as you do?

It's another regime the way I look at it. But maybe I'm wrong
Keep on thinking

[geordief (OP)]

What,I wonder  might be an aggregation of  "quantum objects" that could be bound together in an initial configuration and which would separate into constituent parts either  under an internal or an external impulse?

Does that make any sense as a requirement  or  is that  just not the way things behave on a quantum level at all?

btw do fields move wrt to one another?

[yor_on]

I don't really know Geordie?
QM, hmm, that's a hypothesis, at best

for me, yeah I do take it seriously.
But that's me.

[yor_on]

Think of it this way. If nothing 'vibrates' at that scale although the way we describe it is best fitted by 'vibrations' then that's it. Just like 'Spin'.

No classical perfect 'alter ego', but still a equivalence to it.

[yor_on]

 And yeah, fields has to move relative each other.

[yor_on]

How else would you measure it?

[Colin2B]

Does "relative motion" only apply to classical objects or does the concept apply also in quantum mechanics?

Relativity is as relevant to quantum objects as it is to classical objects.

What,I wonder  might be an aggregation of  "quantum objects" that could be bound together in an initial configuration and which would separate into constituent parts either  under an internal or an external impulse?

How about an atom?

[geordief (OP)]

What,I wonder  might be an aggregation of  "quantum objects" that could be bound together in an initial configuration and which would separate into constituent parts either  under an internal or an external impulse?

How about an atom?

Yes,that sounds right. Can an atom ,in isolation -without external energetic input- break up into its constituent parts?

[Colin2B]

It’s worth looking at spontaneous radioactive decay, where an atom loses some of its constituent parts or changes by emitting photons etc.
An atom would need to be very unstable to break into all of its constituents.

[yor_on]

Atoms are weird, supposed to be timeless at the same time as some can decay radioactively. And also so that what those atoms then produce in form of new particles didn't exist before the decay.