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Electron spin

What is "spin" which is important for quantum computers? Let's talk to Professor Kohei Itoh from Keio’s Faculty of Science and Technology.

Electrons have a characteristic known as spin. Spin has a particular direction, and it creates a magnetic field; if a large number of electrons have their spins pointing in the same direction, they create a large magnetic field and you have a macroscopic magnet. In this video, Professor Kohei Itoh of Keio University explains how the spin of individual electrons can be used as qubits.

For a single electron, the spin can be either aligned with the surrounding magnetic field, which we call spin up, or anti-aligned with it, which we call spin down. We can write these states using the ket notation we introduced when we talked about entanglement and Bell pairs, (|uparrowrangle) and (|downarrowrangle). We then assign one of these to be our (|0rangle) state and the other to be our (|1rangle) state, so that we can use them as variables.




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Understanding Quantum Computers

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