A third road? Strings from a new perspective

[Demystifier]

In
http://xxx.lanl.gov/abs/0705.3542
strings are derived from an attempt to formulate a more fundamental view of quantum mechanics, based on Bohmian interpretation of quantum mechanics. Such a more fundamental view is motivated by some foundational problems of quantum field theory (QFT), such as the fact that there is no particle position operator in QFT, while particle positions are what we really MEASURE in experiments.

What do you think?

 

[Thomas Larsson]

Hrvoje,

In my opinion, which you may or may not care about, your diagnosis is right and reflects a deep physical paradox, but your prescription will kill the patient. The lack of a position operator in QFT is an indication of a fundamental problem, just as the lack of a time operator in QM is. It seems to me that the obvious cure is to improve QFT to include physical rods and clocks, yielding position and time operators.

This viewpoint gives a nice conceptual motivation for renormalization. We expect conventional QFT to be a good approximation in the limit that our rods are very heavy and thus classical, because the outcome of a classical experiment is a c-number. Thus QFT should be a good description for quanta of energy well below the rod mass, which thus acts as a natural cut-off. For non-gravitational theories, which don't interact with mass, it should be possible to take the rod mass to infinity, but the parameters in the approximate QFT description may require renormalization.

 

[Demystifier]

Hrvoje,
In my opinion, which you may or may not care about, your diagnosis is right and reflects a deep physical paradox, but your prescription will kill the patient.

I like the way you said that. Still, when the traditional cures do not give results, sometimes one should try to risk with a more radical treatment. This is what I try to do.