A blog about computer science, software engineering, quantum computing, mathematical puzzles, and so forth.
It all started as I was showing one of our summer interns how to use stimflow to make a quantum circuit. We noticed a stupid bug: adding a flow with start="auto" was failing if the flow was named. Easy fix. I wrote it up, created a pull request on stim’s...
A year ago, I found a way to make quantum attacks on elliptic curve cryptosystems ten times cheaper. Specifically, I found a better way to perform elliptic curve point addition on a quantum computer. I bounce between projects, so it can take me months to get around to writing...
Update (April 26) The competition runners have taken my criticism and my advice (1) (2) (3) . They’re looking for other ideas on how to incentivize open benchmarking of quantum cryptanalysis. I also want open benchmarking, and also generally agree with Project11’s mission and advocacy when it’s...
There are many ways to perform fault tolerant quantum gates: lattice surgery, state injection and gate teleportation, braiding, gauge fixing, code deformation… the list goes on. But, by a large margin, people’s favorite way to do a fault tolerant gate is transversally . A transversal logical gate G is performed...
In this post: why I expect the maximum achievable qubit quality to increase drastically in the next few years. In 2014, the John Martinis group at UCSB performed an experiment where they stored a classical bit using their quantum computer. They protected the bit with a 9 qubit <a...
Recently, I’ve been working on a fast simulator for reversible classical circuits assisted by measurement based uncomputation . Basically it’s just doing the strategy I pointed out back in 2019 . The simulator supports the CCX gate for classical computation, the HMR (Hadamard+Measure+Reset) gate for measurement based computation, and phase...
In 2021, Renou et al published the paper “Quantum theory based on real numbers can be experimentally falsified” in Nature. It caused a decent sized splash at the time. A quick search revealed articles in Quanta and Scientific American and APS News , as well as <a...
In 2001, quantum computers factored the number 15 . It’s now 2025, and quantum computers haven’t yet factored the number 21. It’s sometimes claimed this is proof there’s been no progress in quantum computers. But there’s actually a much more surprising reason 21 hasn’t been factored yet, which jumps out...