3 Qubits and quantum gates: The basic units in quantum computing

 

This chapter covers

  • Comparing qubits and (classical) bits
  • Learning two notations for qubits
  • Understanding how quantum gates allow us to perform operations on qubits
  • Using StrangeFX to visualize the effect of a simple gate

When creating typical applications using classic computers, most developers don’t think about the lowest-level transistors and operations that ultimately allow applications to execute on hardware. Classic hardware is a commodity in the sense that most developers take it for granted and don’t think about it. The details about how it works are not relevant to most applications. High-level programming languages shield us from the low-level (assembly) code, and standards in chip design make it even less relevant for us to understand the physical working of the hardware in a computer.

This was not always the case. In the early days of classical computing, there were no high-level programming languages, and developers worked closer to the bare metal. When the hardware for classic computers became more mainstream and standardized, focus moved to higher-level programming languages.

3.1 Classic bit vs. qubit

3.2 Qubit notation

3.2.1 One qubit

3.2.2 Multiple qubits

3.3 Gates: Manipulating and measuring qubits

3.4 A first [quantum] gate: Pauli-X

3.5 Playing with qubits in Strange

3.5.1 The QuantumExecutionEnvironment interface

3.5.2 The Program class

3.5.3 Steps and gates

3.5.4 Results

3.6 Visualizing quantum circuits

Summary