A word from an editor emeritus and new blog team members!

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With QuTech expanding from a quantum transport research group to a large institute focusing on quantum computers, the number of people walking around in the hallways expands. It makes you almost forget that there are also people leaving. But as the seasons go by, PhD students at QuTech come and go. It gives QuTech its characteristic dynamic character. But it also brings sadness every time we have to wave someone goodbye. And this is exactly what this blogpost is about. Since editorial duties for this blog are performed on a volunteer basis by PhD students (in what little remains of their free time), this means that any editor’s tenure is inherently limited by his or her PhD track. Therefore, with some sadness, we have to say goodbye to Jonas, the founding father of the QuTech blog and involved from the very start. He finished his PhD and moved to Amsterdam. He was an amazing and creative member of the team and we would like to thank him for the time he has spent making this blog an inspirational place for quantum computing.

But of course he wouldn’t leave without equally capable replacement. And, since QuTech is growing, we also extended the editorial team. That is why we proudly announce the two newest team members, Tim and Matteo. Actually Tim and Matteo have been active on the blog for a while. So the time is definitely there for a more official introduction. Continue reading A word from an editor emeritus and new blog team members!

Quantum Computational Supremacy

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by Adriaan Rol

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].

Rather than joining in on the controversy of whether or not Google has really achieved quantum supremacy , I want to focus on some more basic questions: what is quantum supremacy, how does one demonstrate quantum supremacy and why is this such an important milestone?
Continue reading Quantum Computational Supremacy

Quantum internet: at the verge of an emerging technology

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by Bas Dirkse

The internet as we know it today has become an integral part of our lives. We use this piece of technology on a daily, hourly, almost continuous basis. We use it at work, to relax, to socialize, to fact check our friends during an argument and even to control the thermostat at our homes. We can definitely claim that, despite the internet bubble in the 90’s, the technology has far outperformed its expectations of the early 60’s and 70’s in the societal and financial benefits it provided. Will the same bright future be reserved for the quantum internet? Will it deliver the same amount of societal and financial benefits to the world as its classical sibling has done? Continue reading Quantum internet: at the verge of an emerging technology

Counting women in physics

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by Floor van Riggelen

Take a close look at this famous picture. These are the people who attended the fifth Solvay International Conference (1927), where the leading physicists of that time discuss the newly formulated quantum theory. What stands out to me is that this is quite a homogeneous group: 28 white (including Jewish), middle aged guys, plus Marie Curie. Of course, these were different times. Comparing this to QuTech in Delft, the place where I work, (an example of a physics research environment in general) there are some improvements when it comes to diversity. Currently 23% of the QuTech employees are non-European and 17% percent are female, according to a recent official review [1]. However, a quick count on the QuTech webpage will tell you that if you only look at scientists and technical staff [2], this percentage drops to about 10%. At QuTech there are still several scientists who are the only woman in their research group. Looking at it in this way, it seems that not much has changed in almost 100 years of quantum physics. Continue reading Counting women in physics

Diary of an international student at QuTech

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by David Maier


QuTech not only offers a wide range of interesting research, but also a diverse group of employees from numerous countries around the world. As a student from the far away country of Germany I was very curious if I would be able to fit in and overcome the cultural differences. Four months ago I came to Delft for my master’s project. In this little piece I would like to tell you from a humorous perspective about some of the challenges I faced as an international student coming to Delft and how you can overcome them too.

Disclaimer: this text contains irony.
Continue reading Diary of an international student at QuTech

Quantum Information Needs Protecting, and Here’s How to Do It

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by Christophe Vuillot

Quantum physics is the strange and counterintuitive theory of physics governing the tiny world of atoms, electrons and photons. To access such small and ephemeral phenomena, scientists deploy advanced techniques to isolate and manipulate what can be destroyed by the tiniest breeze. Can they further protect these phenomena and make them survive to reach the scale of our life? This will be required to build a functional quantum computer. Continue reading Quantum Information Needs Protecting, and Here’s How to Do It

A quantum network stack?

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by Axel Dahlberg

Summer is approaching fast! The days until vacation are getting fewer and fewer. But before you can relax at a beach with a cold drink you need to send a bunch of emails. However for some reason the software allowing your computer to connect to the Internet has suddenly vanished. What can you do? Well, maybe you can just manually do whatever this software does. It can’t be too hard right? Or can it…?

The network stack, a collection of of software used by computers to connect to each other and run applications over a network, such as e-mail, social media, file sharing, video streaming etc., used by today’s Internet is crucial to its operation. You use it everyday, but do you know what it actually does? When you send an email to your colleague, how is your email actually transmitted across to a different computer?

Continue reading A quantum network stack?

European affairs

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by Barbara Terhal


Recently I had to deal with some bureaucratic business involving a European grant. It concerned the transfer of this grant from one academic institution to another in the form of an amendment.
The transfer had to take place through the interaction of a variety of people, project managers, scientists, upper- and lower-level secretaries, in a EU web portal.
The portal is somewhat like a virtual castle in which one occasionally discovers a door to a hidden room. Once open, the hidden room turns out to give access to new functions and role play, inviting to dress-up and bal masqué, going far beyond the promise of the

Continue reading European affairs

Who’s afraid of Majorana qubits?

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by Guanzhong Wang

Don’t hide it; don’t deny it. I know every time you, my dear friend in or related to the quantum computing community, hear about the words “topological qubits”, you raise your eyebrows slightly and say to yourself, “weird”… Pretend no more! We know you are puzzled why anyone would want to embark on the journey of making a topological qubit and how on earth they go about doing it. In this new series on topological qubits, we will try to explain to you why building such a seemingly unconventional qubit is rather fun and is even one of the natural choices when it comes to quantum computing.

I will start in this post with a virtual lab tour, hoping to give you an overview on where and how we look for the basic building blocks of a topological qubit—a Majorana bound state in condensed matter systems. From the particle that Ettore Majorana envisioned on a piece of paper to the nanowire devices and then back to the blueprints for a topological qubit, this will be a journey linking seemingly strange ideas to real, tangible chips in cryostats. If you’ve ever got curious about a Majorana qubit, gone through some reviews and tutorials but still wonder how experimentalists try to build them, this article is totally for you. If you haven’t, I hope it will arouse your interest in doing so! Continue reading Who’s afraid of Majorana qubits?

Happy Easter: looking for Quantum Eggs

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It’s that time of the year again: the Easter Bunny comes by and hides his eggs. Everywhere you look he hid them: in the flower beds in the garden, underneath your bed, even if you open the cupboards, eggs come rolling out. Eggs in all kinds of clear colours and, if you’re lucky, made of chocolate.

But, over the past year, the Easter Bunny spent his time studying some quantum mechanics. He was inspired and decided to do something totally different this year. Instead of eggs, he hid some quantum terminology in the puzzle below. Can you find all the quantum eggs he hid?

Happy searching!

Can you find all the words?[1]

[1] This puzzle was made at WoordZoekerMaken.nl.
[2] The second ‘l’ in millikelvin got lost during the hiding…