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Designing a logical function for quantum computer is similar to same process for classical one. You can also use truth tables. But you have to design the function to be reversible. Assume you have truth table for logical function $f(x): \{0;1\}^n \rightarrow \{0,1\}$, then reversible equivalent can be build in this way: $$ |x_n\rangle |y\rangle \rightarrow |...


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1) In this step, you connect a teleported qubit with entangled qubits between Alice and Bob. This means, Bob now has an "access" to the teleported qubit. 2) Here you get some information about the teleported qubit and "partially colapse" Bob's qubit according to a state of the teleported qubit. 3) In this last step you bring information about the ...


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As a bare minimum, you would need access to a controlled version of your oracle. This cannot be created from the oracle itself (I'm sure there's already an SE question about this part, but cannot immediately lay my hands on it). A typical construction would allow you to create (Hadamard - controlled oracle - Hadamard) would create an output $$ \cos\frac{f(x)...


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Short answer You are getting that error because your example does not use a valid (normalized) statevector. If you remove the decimals=3 kwarg where you call result.get_statevector it will work. Long Answer The Von-Neuman entropy function in the qiskit.quantum_info works with either Statevector or DensityMatrix object inputs, or inputs that can be ...


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There are two types of information in physics: Classical information Quantum information Physics doesn't answer the question "What is (classical or quantum) information?". This is philosophic question, and physics never answers questions of this kind. Instead, physics answers another question "How (classical or quantum) information is measured?". The ...


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It takes an infinite amount of information to specify the state of a qubit. That's for the reason you said: those two angles to specify the point on the Bloch sphere are continuous, and that means you need an infinite amount of precision. That being said, only one bit of accessible information is gained by measuring a qubit. If you had enough time and ...


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What you're talking about is called a "projection". The projection onto basis state $|\psi\rangle$ is given by: $P_{\psi} = |\psi\rangle\langle\psi|$. Any measurement operator $M$, such as $Z$ can be written as the sum over projectors, weighted by their respective eigenvalues, such that $M = \sum_i \lambda_i P_i$ where $\lambda_i$ is the real-valued ...


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One possible answer I can think of is that two particles that "collide" don't absolutely create an unavoidable entanglement. That was what I was alluding to in the previous question I posted. If entanglement is natural and unavoidable in two colliding particles, then my idea posted here gains validity (I think). But perhaps when two particles collide ...


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You're asking how to prove \begin{equation*} \max_{|φ\rangle_A,|ψ\rangle_B} |\langleφ|_A ⊗ \langleψ|_B |ϕ\rangle_{AB}|^2 < 1 \end{equation*} as opposed to actually answering the question? To prove this, consider the Schmidt decomposition of $|ϕ\rangle_{AB}=\sum_i\lambda_i|\phi^i_A\rangle|\phi^i_B\rangle$, and let $$ |\gamma_A\rangle=\sum_i\lambda_i|i\...


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I'd ignore that hint and instead try to prove the contrapositives: show that a pure state is a product state iff it has one (nonzero) Schmidt coefficient.


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Can someone provide an example of a state $\rho_{AB}$ for which $\sigma^\star_B \neq \rho_B$? Why not start very easily, with a separable state such as $$ \rho_{AB}=\left(p_0|0\rangle\langle 0|\otimes \tau_0+p_1|1\rangle\langle 1|\otimes \tau_1\right) $$ where $\tau_0$ and $\tau_1$ are different (normalised) single-qubit density matrices. We have that $$ I=\...


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This is a very generic description that captures essentially all possibilities of describing the Hamiltonian with a decay process (I supposed one should allow for a general $H_{1,2}$ rather than a simple tensor product of terms)). The basic idea is that if you've got a system ("1"), then if you just describe using a Hamiltonian on that system, the evolution ...


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Play "Hello Quantum" it is a game by IBM on App Store and iTunes Sign up for IBM Q / Quantum Experience - https://www.ibm.com/quantum-computing/technology/experience - when you are there bookmark http://qiskit.org and https://qiskit.org/textbook/preface.html Look for Blogs especially Microsoft's and Jonathan Hui's blogs - they are fantastic! https://www....


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