Mind & Machine, Volume Five

In Persian, the word shāhed means witness. The notion of witnessing something is also significant in quantum physics. In this branch of science, one must assume a balance of many possible truths (for example, regarding the state of a particle) until a measurement is taken, which collapses all possibilities into a single known reality. For students beginning to study quantum physics, a significant challenge is that they can only view the world through mathematical expressions balancing all possible outcomes; they cannot simply see the world of quantum physics directly, and it cannot be modeled faithfully with toys from our macroscopic world.

In Persian classical music, shāhed describes the pitch that has a special place within the music. One could say that it is the witness in the music in the sense that it receives the most attention from the improvising performer or that it is presented to the audience most thoughtfully. Different musical structures include their own shāhed pitches, so treating a pitch like it is the shāhed also evokes realizations about how all other pitches will fit together in their respective relationships to the whole: They lock into one configuration of the state of things.

The word witness carries senses of both seeing and declaring. In quantum physics, the act of measurement sacrifices many possibilities for the sake of knowing one reality, but at a deeper level, in order to study this world that is smaller — more fundamental — than what microscopes can show us, one must sacrifice prior beliefs about how the world works, letting go of knowing anything with complete certainty. Pursuing a deeper understanding of our universe requires patience and bravery to navigate many uncertainties as nature reveals itself to us in its own way.

We are using Persian classical music and electronics to explore our musical sense of the music “locking in” to one state (e.g., a single pitch in the bass drone and one mode in the setār — one pitch becomes the main pitch, around which other pitches orbit) and then going through other musical moments when multiple states could be possible until we hear it locking in again (like the wave function collapsing when measured and broadening in possibilities as further interactions commence). Each pitch we hear gives us a clue as to the relationships among pitches, and when we hear enough of them, our musical sense locks in, resolving uncertainty for the moment and allowing us to feel that now that particular pitch is the shāhed.

This mirrors the phenomenon of state in quantum physics: we can only know the probabilities of multiple possible states in which an object could be, until a measurement is taken, collapsing the wave function of all possibilities. Similarly, the long, pitched drone instrument occasionally locks in on its main pitch (a low E-flat). At other times, it locks in on higher pitches for a moment before returning to its ground state, and sometimes in between, we find it sounding uncertain, rumbling with multiple possibilities existing at once. All these moments of uncertainty resolving into clarity and fleeing back to uncertainty in a cycle keep the music moving forward.

We dedicate our efforts to the brave women of Iran.

— Jeff Morris