Quanta

Quanta is a projet to illustrate quantum concepts and quantum computing using the performing arts.

Music

Clarinettist and composer Fabrice Villard selected pieces from his repertoire that could be used to illustrate various concepts in quantum computing. He is joined in these recordings by saxophonist Pierre-Stéphane Meugé.

Fabrice Villard (Clarinet) and Pierre-Stéphane Meugé (Soprano saxophone). These tracks were recorded at Studio Sequenza for the QuBobs project in December 2025. All rights reserved.

Quanta

The name quanta refers to the fact that in quantum systems, energy makes discrete jumps, from a ground state to the higher excited states. This phenomenon can also be heard in musical instruments where it is known as harmonics. In a wind instrument, if you blow harder, the sound will suddenly jump up an octave, then a fifth, and so on. In this audio clip Pierre Stéphane Meugé demontrates a fundamental frequency and 7 harmonics.

Superposition

According to quantum mechanics, elementary particles behave like waves. A qubit is a binary system, which can be in one of two energy states. We think of the low-energy state , or ground state (binary 0) as a low note, here represented by the clarinet.

The high energy state (binary 1) is represented by high notes, here on a soprano saxophone.

Just like a sound can be composed of many individual sound waves, the state of a qubit can be composed of a high-energy and a low-energy signal. This is called a superposiiton.

The components of a superposition can vary in volume. The amplitude of a signal determines its volume relative to the other components of the signal.

In the piece entitled Bascule, you can hear the saxophone (playing the high notes) start out with the largest amplitude, and gradually, the clarinet takes up more of the amplitude as the saxophone recedes.

Phases

Perhaps the most distinctive feature of waves which is also present in quantum states is that a wave in a superposition can be shifted relative to another wave in the superposition. Such a shift is called a phase. This is similar to the musical form called a canon where one voice starts ahead of the other. In this canon, you can hear the two voices getting shifted further and further from one another as the piece progresses.

When a sound wave is inverted, the result is inaudible but combined with other waves it can cause interference to occur. In the next piece entitled Rebonds, we can hear two melodies which are inverses of one another. In the first excerpt, we can hear the clarinet (low voice) whose melody falls, then rises …

… and the saxophone whose melody first rises then falls

Listen to them in superposition.

Stéréophonie is another example of opposing melodies.

Quantum algorithms

Quantum algorithms use phases and interference to amplify some parts of a computation and attenuate other parts so that at the end, the result has the highest amplitude and can reliably be observed when a measurement of the state is made.

In the piece Emergence - Disparition, the music starts with equal parts saxophone and clarinet and as the piece progresses, one of them emerges as the other one recedes.

Engrenages mixes several of the elements above. We think of it as a playful illustration of what can happen in a quantum computation.