Can the Quantum Computing Speed-up Help the Arts?
The art world is in danger of filling up with quantum computing hype. Alexis Kirke, a Senior Research Fellow at the University of Plymouth, brings us back down to land — so we can take off in a direction that may arrive somewhere useful…
Quantum computers use the unique properties of quantum physics. These are properties that only manifest at the smallest levels of reality. Objects that exhibit quantum properties are smaller than anything we can really experience as human beings. One of the largest is an object made up of only 60 carbon atoms!
So the everyday reality we grew up with does not mirror what happens at these subatomic levels. As a consequence, we feel the quantum-level of physical reality is spooky and bizarre. This leads to much hype in the world of quantum computing about “Entanglement!” and “Superposition!” — properties that are mathematically simple — but that don’t fit in with our direct visual experience of the world.
This “spooky hype” of quantum computing spills over into its applications. Quantum computers have begun to be used to generate visuals, sound and music. These outputs have been described as quantum music or quantum art. In reality, they are all (with a couple of exceptions) either visualisations or “musifications” of quantum computer processes. Or they are created using direct translations of traditional computer algorithms onto a quantum machine. This music and art can be of educational interest and a source of “spooky inspiration”. But it is not quantum computer arts or music research. Quantum computer music uses the underlying quantum hardware in a useful way to do something new.
The music and arts community are not the only people guilty of this hype. The science and technology community perpetuate it as well. Some are producing quantum versions of traditional computer algorithms that have no theoretical or practical advantage over the classical version. But adding the word “quantum” to a title often makes it more noticeable…
Let’s be clear: this sort of pseudo-quantum art has a use. The first computer music tune was the IBM 7094 singing Daisy Bell in 1961. It showed that computers could — in hardware and not just in theory — create a simple musical performance. The first uses of quantum computing in music — Superposition and GATEMEL — did not take advantage of quantum computing to do anything new. They were simply advanced versions of the Daisy Daisy demo for quantum computers.
A case in point, Superposition was the first real-time interactive quantum computer musical performance, which took place at the Port Eliot Arts Festival in the UK. Mezzo-soprano Juliette Pochin’s live singing was transmitted to an adiabatic quantum computer in Los Angeles. A quantum algorithm (qHarmony) on that computer was used to generate harmonies to accompany her. However, qHarmony did not provide any advantage over the classical version of the algorithm.
The quantum advantage is defined here as the potential for a quantum computer to solve problems faster. There are currently only four fundamental quantum algorithms that have been theoretically proven to provide an advantage over their traditional non-quantum equivalent. These algorithms are Shor’s, Grover’s, HHL and various chemistry/physics simulations. Shor’s algorithm can factor numbers (find two unknown smaller numbers that multiply to give a known large number) exponentially faster than traditional computers. HHL is exponentially faster at solving sets of equations known as linear equations. Grover’s algorithm is quadratically faster (takes square-root of the time) at unstructured random search — e.g. to find elements in a database that fulfil certain logical conditions. Chemical and physical simulations cover a vast area — and were the original reason that Richard Feynman proposed quantum computing.
The main purpose of this article is to encourage more computer musicians and artists to do true quantum arts research. In other words art algorithms that utilize the quantum speed-up. I like to call an algorithm that uses a quantum computer but does not utilize the quantum advantage a Pseudo-Quantum Algorithm (PQA). Whereas I define “Quantum Computer Arts” as art generated or supported by non-PQAs whose purpose is specifically artistic (as opposed to music that “represents” non-PQAs).
The only work in computer arts/music published so far that can be theoretically proven to utilize the quantum speed-up advantage is a melody generation algorithm called qgMuse. qgMuse is a computer music system that applies Grover’s algorithm to solving musical equations. The melodies shown in the figures accompanying this article are generated using qgMuse on an IBM quantum computer. qgMuse has various conditions attached to its promised speed-up, not the least of which is that the current batch of live quantum hardware is slow and error-prone. But as the quantum hardware matures, so can algorithms like qgMuse.
