Here we’re gonna see the most impressive quantum algorithm in terms of query complexity. The algorithm is an generalization of the original Deutsch algorithm we discussed in the last post. But I want to say that this algorithm may not be as extraordinary as you may think of it. It was created to solve a kind of problem that has zero practical meaning for the purpose of demonstrating how strong quantum computing can reach compared to classical computing. ...

I have said something like quantum computing can overpower classical computing several times before. In this series, I’m going to showing you a problem with a quantum algorithm that is exponentially faster in terms of complexity than any classical solution. In this text, we’re going to explore an essential technique and apply it to solve the simplest version of Deutsch problem. Phase kick-back One concept you may encouter numerous times in a Linear Algebra class is eigenvalues and eigenvectors. ...

Unlike several rising branches of computer science such as artificial intellgence and machine learning, quantum computing is still young when it comes to the development level. Most widely used quantum programming languages and libraries are created for people to learn and experiment with their ideas rather than for publishing any kind of commercial product. Generally speaking, the field has a weak application side; its focus strongly lies in interpreting quantum information theories and… build some funny stuffs for the sake of learning. ...

About me Hi, my name is Entangled, a cat who adopted a boy named Trong, my hooman slave… I liken’t when he laughed watching videos of other cats showing off their cuteness. He’s textroverted that is apparently energetic in a texting conversation but may dumb as a fish in a face-to-face. Just send him cat footages to get him engaged. Okay, here’s the truth. He’s a coming student at KAIST (Korean Advanced Institute of Science and Technology) and inclined to major in Physics plus Computer Science. ...

Let’s implement and verify the teleporation protocol following the procedure we discussed throughout previous parts. First we need to create an arbitrary quantum state. Trong has been curious about the combined effect of rotation gates about the x, y, and z axes. So, he decides to apply three distinct rotation gates, each as a rotation of 60 degrees around one coordinate axis acting on a qubit currently in the Hadamard state $|-\rangle$. ...

Problem Statement Suppose Trong has just created a wonderful qubit in his lab. He knows his qubit look like $|\psi\rangle = \alpha |0\rangle + \beta |1\rangle$ but doesn’t know $\alpha$ and $\beta$. Now he wants to transport this qubit to his crush, but they don’t have a quantum channel that can help transport quantum information. Of course it’s a very bad idea for Trong to try to figure out $\alpha$ and $\beta$ through measurement because if he does so, he’ll destroy his qubit but only learn extremely little information about it. ...