What is the state vector of the system after measuring a degenerate eigenvalue?(adsbygoogle = window.adsbygoogle || []).push({});

Surely there are infinitely many vectors of norm 1 that it could be since the degenerate eigenvector span a 2d subspace.

Say that we e.g. have a system where the operators eigenvalues are degenerate such that:

(1,0), (0,1) both represent eigenvectors of same eigenvalue. How can we ever know what state the particle is in after measurement?

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# What is the state vector after measuring

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