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Quantum volume

Quantum volume definition 

Quantum volume refers to a metric used to measure the overall capabilities and error rates of a quantum computer, assessing its computational power. Developed by IBM, it provides a holistic measure of a quantum computer's overall performance, taking into account several factors beyond just the number of qubits. The goal of quantum volume is to provide a more comprehensive benchmark for comparing the power and usefulness of different quantum computers.

See also: Post-quantum cryptography, Puantum error correction

How does quantum volume work? 

In classical computing, the basic unit of information is the bit, which can either be a 0 or a 1. These bits are the foundation for all data processing, such as RAM and CPU. Quantum computing introduces a new unit of information — the qubit. Unlike a bit, a qubit can exist in a state of 0, 1, or any quantum superposition of these states. This capability allows quantum computers to process a vast number of possibilities simultaneously.

The calculation of quantum volume involves the following steps:

  1. 1.Defining a model circuit.  The model circuit used has a width and depth equal to the number of qubits, and it involves a sequence of randomly selected gates.
  2. 2.Running the circuit. This circuit is run on the quantum computer to see if it can successfully handle and execute the operations without significant errors.
  3. 3.Analyzing and computing the quantum volume. The outputs are compared against the expected results allowing the calculation of the quantum volume.