If an operator commutes, its inverse commutes

In summary, an operator commutes when it can be rearranged with another operator without changing the result. Not all operators can commute with each other, which can have significant physical implications in quantum mechanics. It is important for an operator to commute with its inverse because it simplifies calculations and problem-solving. If an operator does not commute with its inverse, it can make calculations more complex and may require additional steps to find the correct result. To determine if two operators commute, you can use the commutator, which is equal to zero if the operators commute and non-zero if they do not commute.
  • #1
Boromir
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Prove that if operator on a hilbert space $T$ commutes with an operator $S$ and $T$ is invertible, then $T^{-1}$ commutes with $S$.

$T^{-1}S$=$T^{-1}T^{-1}TS$=$T^{-1}T^{-1}ST$
 
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  • #2
Boromir said:
Prove that if operator on a hilbert space $T$ commutes with an operator $S$ and $T$ is invertible, then $T^{-1}$ commutes with $S$.

$T^{-1}S$=$T^{-1}T^{-1}TS$=$T^{-1}T^{-1}ST$

Start with $TS = ST$ so $T^{-1}TS = T^{-1}ST$. This simplifies to $S = T^{-1}ST$ so ...
 

FAQ: If an operator commutes, its inverse commutes

What does it mean for an operator to commute?

An operator commutes when it can be rearranged with another operator without changing the result. In other words, if A and B are operators, A commutes with B if AB = BA.

Can all operators commute with each other?

No, not all operators can commute with each other. For example, non-commuting operators are common in quantum mechanics and can have significant physical implications.

Why is it important for an operator to commute with its inverse?

If an operator commutes with its inverse, it means that the order in which they are applied does not matter. This can make calculations and problem-solving much simpler and more efficient.

What happens if an operator does not commute with its inverse?

If an operator does not commute with its inverse, it means that the order in which they are applied does matter. This can make calculations and problem-solving more complex and may require additional steps or methods to find the correct result.

How can I determine if two operators commute?

To determine if two operators commute, you can use the commutator, which is defined as [A, B] = AB - BA. If the commutator is equal to zero, then the operators commute. If the commutator is non-zero, then the operators do not commute.

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