https://www.quantumprog.gq/

Review: Quantum Prog

Introducing the “Big Bloch” Sphere

I stumbled upon Quantum Prog in a LinkedIn group and decided to check it out. There are countless visualization tools out there, so how does this one differentiate itself?

The Good

For starters, as you can see in the featured image above, one option is to have what they call a “Big Bloch” sphere. And, as you can see, it is quite a big Bloch sphere. If I was just starting out, I’m sure I would find that quite helpful. In contrast, I have seen some remarkably small Bloch spheres. The additional size ought to be helpful in visualizing rotations.

https://www.quantumprog.gq/

I also like that it has theta control. Not every visualization does. The slider is a bit small and sensitive, but at least it’s there. I would recommend, if I could, allowing values to be typed in.

The Bad

https://www.quantumprog.gq/

This could go either way but, to me, this is a bit cluttered. You could argue that a lot of useful information is available, and I’m not going to argue back. I’d personally be happy, though, with just the Big Bloch sphere and some controls, maybe toggle on/off the rest of it.

The Ugly

https://www.quantumprog.gq/

With one exception, I’ve always seen quantum circuits designed from left to right. In its current implementation, Quantum Prog has you adding gates from right to left. I asked why it was designed this way, and the response was: “It’s because the formula of the matrix product is written from right to left, and it’s clearer to me to read the sequence that way. I plan to add a flip button in the next release.”

Although this belongs under “The Good,” the visualizations are combined here so I’ll note it here and end on a “good” note. The Big Bloch sphere above has “in,” “out,” and also “1” indicated on it. So, the Hadamard is represented as “in” to “1,” and then the S gate is indicated as “1” to “out.” As you add gates, the result of each transformation is numbered. I’ve seen transformations animated before, but I don’t recall seeing them numbered this way before. It’s unique. It’s helpful.

Conclusion

Did I mention Quantum Prog is free? We all learn differently, so when I find free educational utilities I share them. If you need help with visualizing what your qubits are doing, to Quantum Prog’s credit, I’m not aware of a larger Bloch sphere out there. There are different ones, yes, but the Big Bloch sphere is a big Bloch sphere. And, in contrast to zooming in on your screen, you can still use the controls and see the side information because you don’t have to zoom in.