Cafe Einstein: LPTP Triskaidekaphenia

Bit of both really. It is simply stated but the much harder part is 'why is the Universe that way ?'

In a sense one can distinguish two HUP's. Personally I call one Heisenberg Lite, the other Heisenberg Heavy.

The Lite is the one you can just blandly apply to some measurement scheme - the product of the measured spreads of two non-commuting operators has a minimum value - and all is well. You can get very real practical technology out of this eg. mobile phones, great photo-detectors, CCD camera backplanes, tunneling electrons et al. One can extract analogous relationships in classical physics and never mention quantum mechanics at all. A good example is Claude Shannon's work on information in signalling technologies.

The Heavy is more along the lines of 'why is it so?' A good example of this is the 'logical inversion' of HUP Lite : if that measured product a/a is lower bound limited, then an unmeasured thing may have that product as an upper bound. So one can hypothecate 'virtual particles' - by definition never detected or even detectable in principle - that can have any energy you like provided they exist only for a short enough time. These particles are not restrained by the usual energy/momentum relations typical of special relativity and/or . Their influence on 'real' measurements can only be by affecting the probability summations of what are generally subtle experimental findings. Quite annoyingly though : if you assume the virtuals are actually there then the answers come out right with respect to measurement*, and to a very high degree of agreement. If you leave them out then your predictions will clearly disagree with measurement. HUP Heavy then is the discussion of some deeper truth about the structure of space and time, and how physical laws scale. Stuffed if I know what that deeper truth is ....

If you're uncomfortable with this sort of virtual waffle then you are not alone. Sounds very metaphysical, eh ? Debates abound and are unlikely to be settled any time soon in the absence of comparative observations from an alternate Universe(s). What next .... invisible faeries pushing things about, hmmmm ? :-) :-)

Cheers, Mike.

* What was mostly left out of the CERN press releases was that the Higgs particle discovery was actually of presumed decay modes of virtual particle resonances. The actual measurements were of lower energy real particles departing from the scene of an assumed fragmentation scenario. They had to get enough events to pass some statistical thresh-hold - effectively integrating probabilities - to claim a reality behind the theory. It's all self consistent and correct as far as it goes, but it's a very long way from whizz goes the proton along the cloud chamber track as of 1952-ish ...

That sort of stuff happens, it's a known risk of mentioning Heisenberg ! :-)

It's a role I serve around here. But yes, the whole Heisenberg thingy is so counter-intuitive. Even Heisenberg had trouble with Heisenberg. As he grew older he went through a number of phases ( of a philosophical nature ) trying to make his own sense of it.

Cheers, Mike.