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How is the Grover-Algorithm applied to a database?
Question
I want to use the Grover-Algorithm to search an unsorted database for an element $x$. Now the question arises, how do I initialize index and value of the database with the qubits?
Example
Let's say I have $4$ qubits. Thus, $2 ^ 4 = 16$…
alex
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Simulate hamiltonian evolution
I'm trying to figure out how to simulate the evolution of qubits under the interaction of Hamiltonians with terms written as a tensor product of Pauli matrices in a quantum computer. I have found the following trick in Nielsen and Chuang's book…
Apo
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General construction of $W_n$-state
Two of the most well known entangled states are the GHZ-state $|\psi\rangle = 1/\sqrt{2}\left( |0\rangle^{\otimes n} + |1\rangle^{\otimes n}\right)$ and the $W_n$-state, with $W_3 = 1/\sqrt{3}\left(|100\rangle + |010\rangle + |001\rangle\right)$.…
nippon
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What exactly are Quantum XOR Games?
I have done some research & found a few different papers that discuss xor games (classic & quantum). I am curious if someone could give a concise introductory explanation as to what exactly xor games are & how they are or could be used/useful in…
user820789
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What do they mean by "qubit can't be copied"?
What does it mean by ''qubit can't be copied'' ?
In a note, it is saying that:
Copying a qubit means $$U|\psi\rangle_A|0\rangle_B=|\psi\rangle_A|\psi\rangle_B$$
i.e; applying a unitary transformation on the qubit state. It is explained as, if the…
tarit goswami
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Are there any examples of anyone applying quantum algorithms to problems in computational biology?
As the title suggests, I'm searching for published examples of quantum algorithms being applied to problems in computational biology. Clearly the odds are high that practical examples don't exist (yet) – what I'm interested in is any proof of…
Greenstick
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Graphical Calculus for Quantum Circuits
So far I have read a little bit about zx-calculus & y-calculus.
From Reversible Computation:
The zx-calculus is a graphical language for describing quantum systems.
The zx-calculus is an equational theory, based on rewriting the diagrams
which…
user820789
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Status of Google's quantum supremacy claim 2022
More than a year ago a couple of scientists made a splash by presenting a classical algorithm that took less than a week to simulate Sycamore's circuits on a small GPU cluster. Also, their simulations produced exact results and not estimates.
This…
MonteNero
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What use has quantum computing been?
Most of us on this site believe that quantum computing will work. However, let's play devil's advocate. Imagine that we suddenly hit some fundamental stumbling block that prevented further development towards a universal quantum computer. Perhaps…
DaftWullie
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Grover's algorithm: a real life example?
I'm fairly confused about how Grover's algorithm could be used in practice and I'd like to ask help on clarification through an example.
Let's assume an $N=8$ element database that contains colors Red, Orange, Yellow, Green, Cyan, Blue, Indigo and…
01000001
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Jones Polynomial
There are many fairly standard quantum algorithms that can all be understood within a very similar framework, from Deutsch's algorithm Simon's problem, Grover's search, Shor's algorithm and so on.
One algorithm that seems to be completely different…
DaftWullie
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How to input 2 qubits in 2 Hadamard gates?
Let's say we have a circuit with $2$ Hadamard gates:
Let's take the $|00\rangle$ state as input. The vector representation of $|00\rangle$ state is $[1 \ 0 \ 0 \ 0]$, but this is the representation of $2$ qubits and H accepts just $1$ qubit, so…
Archil Zhvania
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How to permute (reshuffle) an n-bit input?
I am interested in a quantum algorithm that gets as input an n-bit sequence and that produces as output a reshuffled (permuted) version of this n-bit sequence.
E.g. if the input is 0,0,1,1 (so n=4 in this case) then the possible answers…
JanVdA
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Is it true to say that one qubit in an entangled state can instantaneously affect all others?
When a qubit is measured, there is a ‘collapse of the wave-function’ as a result is randomly chosen.
If the qubit is entangled with others, this collapse will also effect them. And the way it affects them depends on the way we chose to measure our…
James Wootton
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Does a study guide exist that starts from a "purely CS background" and advances towards "making a new quantum programming language"?
I am from a computer science background and I find it difficult to decide on the resources I should focus on while learning quantum computing, since there is so much to read/watch. My ultimate goal is to make a programming language acting as an…
Kushajveer
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