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Aug 26 at 19:03 answer added Michael Hardy timeline score: 0
Aug 26 at 18:58 comment added Michael Hardy Is this the same as asking whether the expectation of a random unitary matrix invertible? (Where "random" does not mean uniformly distributed, but just means having some probability distribution.)
Aug 26 at 4:32 history became hot network question
Aug 25 at 22:08 vote accept Hans Schmuber
Aug 25 at 21:28 answer added user196574 timeline score: 4
Aug 25 at 21:24 comment added Hans Schmuber If I restrict to the invariant subspace of Hermitian operators, then it looks like this has a trivial kernel, right?
Aug 25 at 21:23 comment added Hans Schmuber From your answer, I can see that if $n=2$, $A=((0,1)(0,0))$ then it is possible to find unitaries with 1 and -1 eigenvalues, then it looks like it has a non-trivial kernel.
Aug 25 at 21:07 history edited Hans Schmuber CC BY-SA 4.0
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Aug 25 at 20:59 comment added Hans Schmuber Thanks for your answer! I'm not sure I understand your counter example. If $A\in \mathbb{R}$, then surely the linear mapping in your example is E(A) = (1/2)*(-1)A(-1) + (1/2)*(1)A(1) = A? But I feel like I've misunderstood you here?
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Aug 25 at 18:08
S Aug 25 at 17:53 history asked Hans Schmuber CC BY-SA 4.0