High School Uncertainty Principle & Non-Commuting Observables

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The discussion centers on the relationship between non-commuting observables and the uncertainty principle, asserting that all non-commuting observables indeed generate an uncertainty principle. The act of measuring one observable affects the certainty of measuring another due to their dependence. This dependence can vary, with "conjugate variables" being a common example linked through Fourier transforms. A generalized uncertainty relation can be formulated for any pair of non-commuting observables, not limited to the traditional position and momentum case. Ultimately, the uncertainty principle is fundamentally tied to the commutator of the observables involved.
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Do all observables which do not commute generate an uncertainty principle ?
 
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The uncertainty principle applies to all observables. The act of knowing that the object does not commute makes you unsure about where it is.
 
Anupama said:
Do all observables which do not commute generate an uncertainty principle ?
Yes you can put it like that, depending on what mean by uncertainty principle.

That observables does not commute simply means that they aren't independent. The details of this dependence can vary depending on what observables we talk about. "Conjugate variables" are related by means of the Fourier transform and is what one most commonly refers to. But in principle one can imagine any relation between independent variables that will imply some kind of "generalized uncertainty relation" that described a relation that constraints their mutual possible values, but not necessarily a simple one like for the case of x and p.

/Fredrik
 
Anupama said:
Do all observables which do not commute generate an uncertainty principle ?

Yes, the general uncertainty principle relates the uncertainty to the commutator of the two observables:

##\sigma_A^2 \sigma_B^2 \ge (\frac{1}{2i}\langle [\hat{A}, \hat{B}] \rangle)^2##
 
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Time reversal invariant Hamiltonians must satisfy ##[H,\Theta]=0## where ##\Theta## is time reversal operator. However, in some texts (for example see Many-body Quantum Theory in Condensed Matter Physics an introduction, HENRIK BRUUS and KARSTEN FLENSBERG, Corrected version: 14 January 2016, section 7.1.4) the time reversal invariant condition is introduced as ##H=H^*##. How these two conditions are identical?

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