Quantum computing ONLY allows for unitary operations. At least in theory, as far as I know. Could we use Quantum Computing to test the limits of Quantum Mechanics or explore the emergence of quantum physics from another bigger scheeeme? What would it happen with quantum computing if we found t...

I'm currently studying A-Level Physics, and have come across a question asking me to calculate the minimum frequency of radiation required, to ionise an atom of sodium. I am given the work function and ionisation energy (2.28 eV and 5.15 eV respectively). The metal is sodium. Is there a formula ...

I was reading these notes http://aty.sdsu.edu/explain/atmos_refr/bending.html and it says that for the temperature gradient of 0.12 K/m the bending of rays matches the curvature of the Earth. I was wondering what the temperature T or temperature gradient T/h must be for a mirage to happen in dis...

It really depends on context. In common use in English language, zero is unsigned, that is, it is neither positive nor negative. In typical French mathematical usage, zero is both positive and negative. Or rather, in mathematical French "$x$ est positif" (literally "$x$ is positive") allows the...

I'm really confused by the definition and uses of operators in quantum mechanics. Usually we say that the state of a system is described by some vector $\lvert\psi\rangle$ in a Hilbert space $H$, and then we define operators acting on said vector, for example $\hat{p}: H\rightarrow H$. But often ...