Recent content by rmp251

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    Discrete Fourier Transform of Even Function

    I was missing the f(0)=0 requirement. Makes sense now. Thanks a lot for the insight!
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    Discrete Fourier Transform of Even Function

    Why do we need f(-1)=f(15) = -1 ? We have f(-1)=f(15) by periodic extension. And f(-1)= -f(1) = -0.8315. We're talking about odd meaning antisymmetric about the f axis (n=0), correct?
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    Discrete Fourier Transform of Even Function

    I understand... except the part where you say the function is not exactly odd. Based on what you're saying, if we extend the signal beyond n=0..N-1 to make it periodic, then isn't it exactly odd (regardless of any discontiniuity)? Thanks all for the responses!
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    Discrete Fourier Transform of Even Function

    The code is pretty simple: N=16; n = [0:N-1]; f = cos(3*pi*n/N); F = fft(f,N); The resulting F is: 1.0000 1.0000 + 4.1412i 1.0000 - 5.6858i 1.0000 - 2.0586i 1.0000 - 1.2027i 1.0000 - 0.7609i 1.0000 - 0.4596i 1.0000 - 0.2180i 1.0000...
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    Discrete Fourier Transform of Even Function

    I'm confused about the DFT of the data, fn = cos(3\pin/N) for n=0,1,...,N. It is definitely an even function, and I read that the Fourier coefficients of an even function is real. But when I take the FFT of this in Matlab I get complex numbers, not real numbers. What am I missing? Thanks ...
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    Inner product with maximally entangled state

    Sorry I realize that was a little incomplete. Let \mathcal{X} and \mathcal{Y} be complex Euclidean spaces with dim(\mathcal{X})=dim(\mathcal{Y})=n. Define M(\rho) = \max\left\{<u u^{\ast},\rho>\,:\,u\in\mathcal{X}\otimes\mathcal{Y}\;\text{is maximally entangled} \right\}...
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    Inner product with maximally entangled state

    Consider the maximum inner product of a density operator with a maximally entangled state. (So, given a density operator, we're maximizing over all maximally entangled states.) I'm pretty sure the minimum value (a lower bound on the maximum) for this is 1/n2, using the density operator 1/n2...
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    Is the Holevo Quantity Preserved under Channel Applications?

    I'm trying to prove that the Holevo quantity does not increase when a channel is applied to the ensemble of states. So, if \Phi(ε) = { (p(a), \Phi(ρa)) : a\in\Gamma}, then I want to prove that \chi(\Phi(ε)) ≤ \chi(ε) where \chi refers to the Holevo quantity. I'm trying an...
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