# All Questions

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### How to prove that a $d$-dimensional Hilbert space can only have $d^2$ equiangular vectors (i.e. that a SIC is a maximal collection of that kind)?

It is an open question if every $d$-dimensional Hilbert space contains a collection of $d^2$ states, such that every two have a scalar product of $\frac{1}{d+1}$, i.e. if a SIC-POVM exists for every ...
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### Measuring inner choke point on non-uniform silica capillary tube

I hope this is an appropriate place to be asking questions like these (google brought me here when I was searching for a solution)! I make an assembly where a small silica capillary tube (OD of 1mm) ...
25 views

### Representation of spin-$1/2$ operators in terms of Majorana fermions

I am reading Quantum Field Theory in Condensed Matter Physics by A.M. Tsvelik. In Chapter 20, it is claimed that introducing three Majorana fermions $\gamma^\mu_i$ on each site $i$ of the lattice (...
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### Event horizon area and entropy content of a black hole

I am aware that the entropy content of a black hole is proportional to the area of its event horizon, and that this can be boiled down to the bit content of a Planck area on the horizon, but I have ...