Posts by Adriaan Rol

Good UX: Non-thinking versus minimizing cognitive load

A common design principle is “don’t make me think”. It might even capture an essential aspect of good (user) design. However, pushed to its extreme, it can lead to some very bad UX and frustrations. In this blog post, I will argue for adopting “minimize cognitive load” as an alternative design principle.


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Enabling giscus comments on all posts

To avoid having to add the giscus comment snippet of the previous post to every post, I want to add it to the page template. To do this, we first need to set up Sphinx to look for custom templates, figure out a good starting template, and then modify it to our liking.

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Allowing comments using giscus

As my personal website is basically a blog, I’d like readers to be able to comment on it. Previously, I used Disqus for it, but I don’t really like the look and feel of it, and when googling around I found that it is also obnoxious with tracking, adverts and generally disrespecting privacy. One of the alternatives that I was quite charmed by was giscus, a solution that uses GitHub Discussions to power the comments and reactions to my blog posts. In this post, I’ll show how to set up giscus for my Sphinx based website.

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Migrating the website to Sphinx + ABlog

Last week I migrated my website from Nikola ( see my post from 2020 )to Sphinx + ABlog. Although it might look a little different than before, the functionality is essentially the same so you might wonder why I decided to do this migration.

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Obsidian, making me love taking notes again

I have recently fallen in love with a new note-taking app: Obsidian. Obsidian is a note-taking app that brands itself as a “second brain”. It is a knowledge base build on top of a local folder of markdown files. In practice, this combination makes it both one of the simplest, and one of the most powerful note-taking apps I have ever used.


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A Practical Guide for Building Superconducting Quantum Devices

I’m very excited that our tutorial on cQED, the technology behind superconducting qubits, got published in PRX Quantum today! I hope this work will make it easier for anyone looking to get into this fascinating field.


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Accelerating quantum computer developments

With Orange Quantum Systems, and our partners in the Dutch Quantum ecosystem we have published a paper in the special quantum industry issue of EPJ Quantum Technology on accelerating the development of quantum computers. In this paper, we present the product development approach and roadmap for quantum computers, based on superconducting circuits as an example.


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Quantum Delft webinar on Quantify

I gave a presentation at the Quantum Delft webinar on Quantify, and our work on running variational algorithms (VQE) on the Quantum Inspire. Quantify, is an open-source framework for operating quantum computers in the NISQ era developed by Orange Quantum Systems and Qblox

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Setting up a new python project with Cookiecutter

Every so often, I need to set up a new repository for a python project including a lot of boilerplate. Because you only set it up once I always spend a lot of time googling best practices and reinventing the wheel. To resolve this once and for all I decided to make a template tailored to my own preferences.


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Uploading a package on PyPI

These are some simple notes to remind myself how to upload a python package to PyPI. The full description on how to upload a package to PyPI can be found here.

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Invitation to the public defense of my doctoral thesis

Nederlandse versie.


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Buying cryptocurrency

I have always been very skeptical about cryptocurrencies such as Bitcoin. However, now that printing money is considered a valid response to the corona crisis, and is likely here to stay, I like the idea of having a currency of which there is a fixed supply. Previously I considered cryptocurrencies too speculative, mostly because I did not, and still do not, fully understand how they work. I am investing a small amount into cryptocurrencies as an experiment, where I intend to learn about these instruments, and potentially make a small profit. I found Investopedia to be one of the best resources on getting started with cryptocurrencies in general.

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Git basics

A few years ago, I made a flowchart to serve as a reference for basic Git usage for the Casimir Programming Course. The flowchart is intended to serve as a reference for the novice who has learned about the basic concepts of Git. For a proper reference on Git, I would recommend the Pro Git book I hope this flowchart is helpful to some, enjoy!


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Quantum Inspire Launch

Last week I had the pleasure of being part of the Quantum Inspire launch event. Quantum Inspire is Europe’s first public quantum computer, and the world’s first multi-qubit platform with both a transmon and a silicon-spin backend. You can read my summary of the discussions we had during the event on the Orange Quantum Systems website or watch the recording here.

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How to deal with conflicting views

Based on some of my former writing you may expect to find mostly technical articles here. However, I have always been interested in not just content (what) but also in form (how). The latter has led to an interest in business, leadership, and processes. Subjects which in my mind can no longer be completely separated from technical discussions. In this post I will reflect on the question: What do you do when you disagree with someone on e.g., a technical matter? This discussion is based on my personal experiences and views but I think the ideas can, to a large extent, be generalized. I am looking forward to your thoughts and comments. Let me know where there is a flaw in my reasoning, where the logic doesn’t apply or any other views you have on the matter.

Richard Feynman

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Building a site using Nikola

Building a personal website is something that shows up on my personal todo/ideas list from time to time. My main motivation for doing so is to use it as a means to learn. I find that writing, and in particular explaining things, is an excellent way to structure one’s thoughts and learn things. On a practical level I hope to get a better understanding of all the technical aspects involved in building a website. This post describes the technical steps I took to build this site and is intended to serve as a future reference to myself or to others interested in setting up a personal site using Nikola.

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Cryoscope featured on the cover of Applied Physics Letters

Our paper presenting Cryoscope recently got published and is featured on the cover of Applied Physics Letters. Cryoscope is an in-situ technique which uses a qubit to accurately sample the flux pulses used to dynamically control its frequency. This measurement is key for determining the linear-dynamical distortion on the flux control line and later correcting it, as needed for high-fidelity two-qubit gates.


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Quantum Computational Supremacy

Last week Google and collaborators published a paper in which they claim to have achieved Quantum Supremacy , one of the major milestones in quantum computing. The idea of quantum supremacy is to use a programmable quantum device to perform a task that is out-of-reach for any classical computer Google claims to have solved a problem in seconds that would take tens of thousands of years on a state of the art supercomputer. The quantum supremacy experiment has been a long-standing milestone in the field of quantum computation, and as such, skepticism has arised; soon after publication of the article a group in IBM research has challenged the results [1].


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Net-Zero two-qubit gate published in Physical Review Letters

We have recently developed a new type of conditional-phase gate for transmon qubits providing several key improvements over standard flux-pulsing-based versions. The Net-Zero gate uses “leakage interference” to minimize leakage to non-computational states. The zero-average, bipolar shape of the pulse makes the gate robust to long timescale distortions in the flux control line and additionally provides an echo effect. We demonstrate a state-of-the-art conditional-phase gate of duration 40 ns achieving 99.1% fidelity and 0.1% leakage.


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Building blocks of a Quantum Computer

Last May we recorded the lectures for the QuTech Academy online course Building blocks of a Quantum Computer. Recording the MOOC was quite fun. You can see the result here. In this lecture I explain how two-qubit gates work in transmon qubits.

Recording a lecture for the MOOC building blocks of a Quantum Computer.

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Why turning a ket into a cat may or may not be a good idea

People often ask me what I do. There is a lot of things I can talk about: why is a quantum computer interesting or useful , or what do I actually do during my day. But quite often people end up asking a confused question about this curious story of an undead cat. In this blog post I will try to shed some light on this case as well as delve into the question of why we use these kind of stories.


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