Operators with commutator ihbar

In summary, the commutator of any position and its conjugate momentum is always ihbar, according to Dirac's substitution of the Poisson bracket algebra. This holds true for both linear and angular position and momentum, making it a unique result for any combination of two different operators.
  • #1
lonewolf219
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I know that the commutator of the position and momentum operators is ihbar. Can any other combination of two different operators produce this same result, or is it unique to position and momentum only?
 
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  • #2
Any position and its conjugate momentum have commutator [itex]i \hbar[/itex].

It's not just linear position and momentum,
[itex] [x,p_{x}]=i\hbar[/itex],
but angular position and (the proper component of) the angular momentum (the component being the one parallel to the axis of rotation),
[itex] [\theta,L_{\theta}]=i\hbar[/itex].

Going into a bit more detail:
According to Dirac, one way of getting quantum mechanics from classical mechanics is by substituting the Poisson bracket algebra with i hbar times the corresponding commutator algebra.
[itex][\hat{q_{j}},\hat{p_{j}}] = i \hbar \{q_{j},p_{j}\} = i \hbar[/itex].
Assuming this always works, then the commutator of any generalized coordinate with its conjugate momentum will always be i hbar.
 
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  • #3
Thank you, jfizzix... That is a very helpful answer! Thanks for posting !
 

FAQ: Operators with commutator ihbar

What is the commutator of operators with ihbar?

The commutator of operators with ihbar, denoted by [A,B], is a mathematical expression that represents how two operators A and B interact with each other. It is defined as [A,B] = AB - BA, where AB represents the product of the two operators in one order and BA represents the product in the opposite order.

What is the significance of ihbar in the commutator of operators?

Ihbar, also known as the reduced Planck constant, is a fundamental physical constant that appears in the commutator of operators. It has a value of approximately 1.0545718 × 10^-34 joule seconds, and it relates the wavelength of a particle to its momentum. In quantum mechanics, it plays a crucial role in determining the uncertainty in the measurements of physical quantities.

How do operators with ihbar relate to Heisenberg's uncertainty principle?

Operators with ihbar are related to Heisenberg's uncertainty principle through the commutator of two conjugate operators. This principle states that it is impossible to know the precise values of certain pairs of physical quantities, such as position and momentum, simultaneously. The commutator of these operators with ihbar reflects this uncertainty by having a non-zero value.

What is the physical interpretation of the commutator of operators with ihbar?

The commutator of operators with ihbar has a physical interpretation in quantum mechanics. It represents the non-commutativity of certain physical quantities, which leads to the uncertainty principle. It also plays a crucial role in determining the compatibility of quantum observables and the evolution of quantum systems.

How does the commutator of operators with ihbar affect the measurement of physical quantities?

The commutator of operators with ihbar affects the measurement of physical quantities by introducing uncertainty in the measurement process. This uncertainty is a fundamental aspect of quantum mechanics and is related to the non-commutativity of certain operators. It is important to consider the commutator when making precise measurements in quantum systems.

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