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visits member for 3 years, 2 months
seen Mar 6 at 14:20

Feb
22
asked Question about electron-hole pair generation in depletion layer for a p-n junction photodiode
Feb
11
comment How would a quantum computer receive input from a classical computer?
Insert a grad student between the classical computer and the quantum computer.
Feb
10
comment How are the field operator and quantum state after a beam splitter and a polarizing beam splitter individually?
For a non-ideal PBS, the situation would of course be more complicated. Nonetheless, my feeling is: if you can properly model the action on a single photon with arbitrary polarization, then the action on an arbitrary state could also be evaluated (should be a few lines of code).
Feb
10
comment How are the field operator and quantum state after a beam splitter and a polarizing beam splitter individually?
It shouldn't be a problem for an ideal PBS. The basic transformation would be as follows: $|m^a_H, n^a_V ; p^b_H, q^b_V \rangle \rightarrow |p^c_H, n^c_V ; m^d_H, q^d_V \rangle$, with $m, n, p, q$ denoting arbitrary photon numbers, the superscripts [subscripts] denoting the spatial [polarization] modes. Since you can represent any state in the Fock basis, the above transformation for some multiphoton state containing both polarizations can also be accordingly evaluated.
Feb
8
revised How are the field operator and quantum state after a beam splitter and a polarizing beam splitter individually?
Added figure and reference.
Feb
8
comment How are the field operator and quantum state after a beam splitter and a polarizing beam splitter individually?
@LuZhang : I've updated the answer with a figure and a reference. Hope that helps!
Feb
8
revised How are the field operator and quantum state after a beam splitter and a polarizing beam splitter individually?
Added figure and reference.
Feb
5
comment How are the field operator and quantum state after a beam splitter and a polarizing beam splitter individually?
@LuZhang: I wrote an answer. Let me know if that clarifies your doubts.
Feb
5
answered How are the field operator and quantum state after a beam splitter and a polarizing beam splitter individually?
Feb
5
comment How are the field operator and quantum state after a beam splitter and a polarizing beam splitter individually?
You don't need any prefactors for a polarizing beam splitter (PBS), i.e. $\hat{a}_{\rm out1} = \hat{a}_{\rm H}$ and $\hat{a}_{\rm out2} = \hat{a}_{\rm V}$. An ideal PBS will always transmit [reflect] all the horizontally [vertically] polarized photons.
Feb
4
comment Query about the proof why non-orthogonal states cannot be reliably distinguished
Let $A$ be a positive operator s.t. $\sqrt{A} |\psi \rangle = 0$. If the eigenvalues of $A$ are $\lambda_0$ and $\lambda_1$ and $|\psi \rangle = \alpha |0 \rangle + \beta |1 \rangle$ for arbitrary $\alpha$ and $\beta$, then the equation $\sqrt{\lambda_0} \alpha + \sqrt{\lambda_1} \beta = 0$ need not imply $\lambda_0 \alpha + \lambda_1 \beta = 0$, right?
Feb
4
comment Query about the proof why non-orthogonal states cannot be reliably distinguished
@Phoenix87 : I am not so sure if $\sqrt{E_2} |\psi_1 \rangle = 0$ also necessarily implies $E_2 |\psi_1 \rangle = 0$.
Feb
4
comment Query about the proof why non-orthogonal states cannot be reliably distinguished
@NorbertSchuch And this works only because $E_1$ and $E_2$ have a spectral decomposition because otherwise the $\sqrt{ }$ operation cannot be defined, right?
Feb
4
comment Why breakdown voltage decreases with increasing FWHM of an asperity?
FWHM (which presumably is full width at half maximum) of what exactly?
Feb
4
asked Query about the proof why non-orthogonal states cannot be reliably distinguished
Feb
2
revised Laser beam photon counting
minor improvements
Feb
2
answered Laser beam photon counting
Jan
20
comment How can I make an optical circulator?
You would need a minimum of 2 isolators and will also incur $\geq 3\,$dB loss.
Jan
20
revised Phase shift in back-reflection generated at the mating point of two fibers
expired link changed
Jan
20
awarded  Promoter