Quantum Computing

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Quantum Circuits

In this section we introduce quantum circuits, a common notation used for communicating quantum algorithms.


  1. Quantum Circuits
  2. A Simple Quantum Algorithm (Random Number Generator)

Quantum Circuits

We normally start with our qubits in the state |0⟩, and perform a sequence of operations on them. We use quantum circuits to show this: each line represents a qubit, each box represents an operation and the operations are carried out in chronological order from left to right.

Example Algorithm: Random Number Generator

We now know enough to create our first quantum algorithm! We start with possibly the most simple algorithm we can think of on a quantum computer- a true random number generator.


  1. Start with each qubit in the state |0⟩
  2. Apply an H-gate to each qubit
  3. Output measurement of the register

After the H-gate, the state of each qubit is |+⟩ which gives equal probability of measuring |0⟩ and |1⟩. This is a truly quantum algorithm (cannot be perfomed on a classical computer).

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