**Quantum Computer Meets Pen Plotter**

I recently purchased an Axidraw v3 pen plotter, which can faithfully reproduce vector artwork on a drawing surface using any drawing tool, such as a micron pen (or a gel pen, in my case). This may seem like a funny little retro device to pair with a quantum computer, but I believe it is the perfect instrument for generative quantum art. To me, a computer is probably the best tool mankind has ever made, but there is a disconnect between digital media and traditional analog media. I love the imperfections, the material, and the textures of using traditional media. With a pen plotter and a quantum computer, I can get the best of both worlds. It feels particularly fitting to “print” generative quantum artwork with a pen plotter, because a quantum computer itself is not digital and is very error-prone. Using an analog printing method with an analog computer feels right.

**Quantum Alphabet**

The Quantum Alphabet is an art series depicting an artistic interpretation of all 26 letters of the English alphabet using data generated by a quantum algorithm and plotted by a pen plotter. But the series also tells a story about the basic building blocks of communication for both our written language and the language of quantum computers. I’m really excited about this work because it is the first full series of generative quantum art that I have done — it might be the first art series generated by a quantum computer, period.

**Let’s talk tech**

Since I generated every letter in the series with a quantum computer, we should probably discuss the technical details before we get into the artwork itself. The binary representation of each letter (for example, `A = 1000001`

) is fed to the quantum oracle from the Bernstein-Vazirani Algorithm, which you can read more about in the Qiskit textbook here and in a previous art project of mine here, and measured roughly 1000 times on the `ibmq-paris`

quantum computer. The computer returns the data in binary, and this output becomes the corpus that I map to the pixels of each letter.

Because of the limitations of current quantum computers, the data is full of errors, which are core to the aesthetic of this series. Binary is at the root of all computational data, and for this series I’m using it both as a number and as a letter. Every time the quantum computer correctly returns the binary for the given letter, the code instructs the pen plotter to draw a red square and the system moves on to the next pixel. Every time the value is incorrect, the code converts the binary value to a number and uses this number to determine the size of a pen-drawn shape or line, then once again the pen moves on to the next pixel. The system iterates over the entire letter in this fashion with each pixel referencing each measurement from the quantum computer. The final compositions are the letters you see in this series.

All of the code for the project is available on my Github here. Still with me? Good. Let’s talk art.

**Quantum computing is surprisingly human**

In written languages, the basic unit of communication is a letter. To a quantum computer, the basic unit of communication is a logic gate. In both, we can string together these basic units in meaningful ways to communicate something. But quantum logic gates have quantum problems. Quantum states are fragile and don’t last very long. The more logic gates added to a quantum circuit, the longer it will take to execute, and the more likely it is to fail. I use artistic license to show this over the progression of the quantum alphabet. At the beginning of the alphabet with the letter “A”, the lines are clean and nothing overlaps. By the time we reach “Z” the lines are scratchy, overlapping, and unwieldy. In a real quantum circuit, the earlier logic gates perform as intended with fewer problem, but the longer the circuit, the less accurate the later gates will perform. The “Z” is still recognizable as a “Z”, but noise is beginning to overtake it.

Each letter is composed of a series of small shapes: squares, triangles, hexagons, lines, and combinations of lines. These are the individual “quanta” of the letter. The shapes are purely aesthetic, but the size of the shape is determined by the value returned by the quantum computer. For example, if the quantum computer returns the string `1000001`

, that binary value is converted to its number value, which is `65`

. The `65`

is used as the initial pixel size of the shape. The next value may be `0000101`

, which converts to `5`

, so the following shape would have a size of `5`

pixels. The two shapes next to each other would be very different sizes, which is exactly what happens in each letter.

The initial units were in pixels, but the pen plotter uses vector shapes, so the initial pixel values were used to scale the vector shapes. As the alphabet continues, I use a multiplier to scale the size of the shapes as a part of the narrative of the letters corresponding to the quantum logic gates being influenced by noise. The values are based off the data from the quantum computer, but it was an artistic decision to scale them per individual letter.

# All together now

When all the letters are juxtaposed together, as in the image below, the real discrepancy in the performance of the quantum systems against different circuits becomes evident. Even though I made some artistic decisions with the shapes and their scale, the final composition is still driven by quantum properties and I had no idea how the final compositions would be manifested.

This is what I like the most about quantum computing. I love the analogue and fallible nature. A quantum computer is like tricking the fundamental building blocks of nature into doing a computation, and despite our best efforts, we will never be in complete control. There are theories and methods to mitigate noise, but regardless, probability and interference are fundamentally a part of quantum mechanics. And for near-term quantum devices, working with the noise is an unavoidable part of the process.

I started by saying the computer is the best tool mankind has invented, and that’s because we are able to put mathematics to work for us. With a quantum computer, we are putting nature to work for us. When quantum computing meets art, it only feels appropriate to use a plotter with a traditional pen against traditional media to showcase the power of a computer driven by nature.