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 Apr 18 awarded Popular Question Feb 26 awarded Popular Question Dec 22 awarded Yearling Sep 15 revised What is the meaning of conformal mass on a branched manifold? edited body Sep 15 revised What is the meaning of conformal mass on a branched manifold? edited body Sep 15 asked What is the meaning of conformal mass on a branched manifold? Sep 15 asked Standard references in (holographic) entanglement entropy literature (Part 2) Aug 23 comment Standard references in (holographic) entanglement entropy literature (Part 1) Thanks! May be you can help with the references for the rest too? Aug 23 comment Standard references in (holographic) entanglement entropy literature (Part 1) You know what is the reference to this? Aug 23 comment Standard references in (holographic) entanglement entropy literature (Part 1) S_A is the entanglement entropy of the subsystem A. Aug 23 asked Standard references in (holographic) entanglement entropy literature (Part 1) Jul 21 asked Representation theory and the Nekrasov partition function Jul 18 awarded Nice Question Jul 12 comment Why does a measurement on one qubit force another one into a given state in Simon's algorithm? I think the issue is as to what do you mean by "measuring in the computational basis". What is this? This is what is forcing the collapse into the $\psi_b$ states. This would make sense only if the measurement is by an operator for whom the $\psi_b$ are the eigenstaes. Jul 12 comment Why does a measurement on one qubit force another one into a given state in Simon's algorithm? That $\psi_a$ is a linear combination of the $\psi_b$s can't be the reason why the wave-function collapses into only the $\psi_b$ states! One could have as well chosen a different basis to expand the $\psi_a$s in and gotten a different result! Jul 12 comment Why does a measurement on one qubit force another one into a given state in Simon's algorithm? CLARIFICATION : But the probabilities don't add up rightly either $\sum_b ( \bar{\psi_b} \psi_a )^2 = 2$. Wonder is the interpretation of the fact that the probabilites over all these possibilities seem to add up to $2$! Jul 12 revised Why does a measurement on one qubit force another one into a given state in Simon's algorithm? added 12 characters in body Jul 12 comment Why does a measurement on one qubit force another one into a given state in Simon's algorithm? Also These $\psi_b$s do NOT seem to have this property that they are able to span the entire Hilbert space. They are not a basis. The probabilities don't add up either $\sum_b ( \bar{\psi_b} \psi_a )^2 = 1/2$ Then it becomes more unclear as to why you think something which is not of the $\psi_b$ will not be observed. Jul 12 comment Why does a measurement on one qubit force another one into a given state in Simon's algorithm? (1) So is this measurement measuring a certain observable/(Hermitian operator) whose eigenstates are theses $\psi_b$s? Then that makes perfect sense that the observation is one of these $\psi_b$s. (to give an alaogy given a spin 1/2 if one measures its spin in the x direction then its no surprise that one would get either the $|1/2,(1/2)_x>$ or $|1/2,(-1/2)_x>$ state) (2) Can you explain what is a "computational basis"? What do you mean by "measurement on the second register is made in the computational basis" ? Jul 12 comment Why does a measurement on one qubit force another one into a given state in Simon's algorithm? Clarification : I mean that the observation could have collapsed it to may be any of the vectors in this $2^{2n}$ dimensional vector space. But then why are these $\psi_b$s special? Is this observation by an operator such that $\psi_b$s are its eigenstates? Then that would make sense.