Is concurrency hard?

[Marc van Woerkom]

>On dear - who is right? - both - it is the question that 
>is silly - you cannot ask questions about 
>the simultaneity of event occurring at different places 
>(basic physics).

Each one has his own correct point of view about the 
events happening, and it is possible to find out what is 
going on in another observer's local coordinate frame (one 
knows the proper transformations).


>Now in physics there is no concept of sharing and no 
>concept of simultaneity at 
>a distance. We can only say that two things occur at the 
>same time if they occur at the same place. 

The theory of relativity has abandoned absolute time, that 
is true.

One the other hand we have that strange world of quantum 
mechanics.
There you have the odd phenomenon of coupled states.
E.g. certain radioactive isotopes have an event, where two 
photons are emitted in opposite directions. The 
polarisation of the photons is undetermined at first. 
But if you measure one photon, and thus force nature to 
make a choice, instantenously the other photon takes the 
opposite polarisation.

The interesting bit is that people start to employ such 
odd quantum effects to create unique and potentially more 
powerful computing devices. 
The world is quantum, not classical, so let's use that!
Read a text on quantumn computing to see what interesting 
combination of theoretical computer science and quantum 
physics has been developed so far.
E.g. the above mentioned coupled photons are used to 
realize secure communication channels.


>In physics, light propagates through a media (called the 
>ether) - but nobody
>knows what the ether is. 

Since 100 years, the annus mirabilis of Albert Einstein, 
ether has been abandoned. 

Regards,
Marc