Welcome to the NISQ Era

We have seen that qubit operations are not perfect and that with every operation, some error is introduced. We have also seen that we can only maintain quantum states for a specific amount of time due to decoherence. Both aspects limit the number of operations we can perform.

NISQ = Noisy and Intermediate-Scale Quantum

The NISQ (Noisy Intermediate-Scale Quantum) era refers to the current stage of development of quantum computers, where the available devices have a limited number of qubits available (a few dozen to a few hundred), and are subject to noise and errors.

IQM Garnet (see image below) is a 20-qubit quantum computer from the NISQ era. It is common for these devices that not every qubit is connected to every other qubit. Instead, only certain qubits are interconnected.

An actual quantum processor

The image below shows another superconducting quantum processing unit with 4 qubits instead of 20. Please keep in mind that not every superconducting quantum chip looks like this. It is only one way to realize a superconducting quantum processing unit.

Hints on the different elements

Qubit

A qubit is the fundamental building block of a superconducting quantum processor. It is an artificial version of an atomic system representing one quantum bit.

Drive Line

A drive line is responsible for delivering microwave signals to manipulate qubits and drive quantum operations.

Flux Line

A flux line controls the magnetic field applied to a qubit and therefore adjust the qubit frequency.

Readout resonator

A readout resonator detects and amplifies the signal from a qubit to perform measurements at the end of a computation.

Launchpad

Multiple launchpads provide the connection to the outside world.

As one might expect, incorporating additional qubits onto a single chip necessitates a greater number of inter-qubit connections. However To address this, researchers are actively advancing the development of more powerful quantum computers by implementing three-dimensional configurations