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


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


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


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


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

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


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

Happy Easter: looking for Quantum Eggs


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…

Stitching Qubits


How to add qubits to an array one by one.

by Anne-Marije Zwerver

So it is winter and it is cold. Cold? It is freezing! But the air is nice and dry outside, so you decide to take a wintery walk in the forest. If you’re in a part of the world where you can currently fry an egg on the street, just wander along in your head – this is a small gedanken experiment. The walk is nice, yet cold and by the time you arrive home, the only thing you want, is to take a nice and warm shower. You turn on the tap and you feel the water running, splashing on your arms and shoulders, slowly defrosting your fingers. But then, for goodness sake, your roommate turns on her (cold) tap and your water temperature rises instantly. In a reflex, you jump out of the water jet, your skin already showing red stains. Luckily it was just an instant and soon you can go back into the shower. But then, of course, your other roommate needs some hot water and with a scream you, again, jump out of the now ice-cold shower. Time for a cup of tea…

Continue reading Stitching Qubits

How can we speed up the quantum internet?


by Suzanne van Dam

What if we could make an internet, but quantum? This would allow us to connect distant nodes (e.g. computers) not with classical information, but with quantum information. We can already imagine cool applications, such as secure communication
guaranteed by the laws of quantum physics. But many of the applications may not even have been dreamed up yet,
as happened before with new technology.
Continue reading How can we speed up the quantum internet?

A Quantum Internet made of Diamonds


How cool is that? A Quantum Internet. Made of Diamonds.

by Matteo Pompili

We are constantly connected to Internet. With our computers, our smartphones, our cars, our fridges (mine is not, yet, but you get the idea). In its very first days, the Internet was a very rudimentary, yet revolutionary, connection between computers [1]. It enabled one computer on the network to send messages to any other computer on the network, whether it was directly connected to it (that is, with a cable) or not. Some of the computers on the network acted as routing nodes for the information, so that it could get directed toward the destination. In 1969 there were four nodes on the then-called ARPANET. By 1973 there were ten times as many. In 1981 the number of connected computers was more than 200. Last year the number of devices capable of connecting to Internet was 8.4 billion (with a b!) [2].
Computers on their own are already great, but there is a whole range of applications that, without a network infrastructure, would be inaccessible. Do you see where I am going?
Continue reading A Quantum Internet made of Diamonds

Looking back at the DiVincenzo criteria


by David DiVincenzo

The first time that I heard that there were “DiVincenzo criteria” was when Richard Hughes of Los Alamos contacted me in the fall of 2001, telling me that ARDA (predecessor of IARPA – a funding agency of the US intelligence services) had commissioned him to form a roadmap committee to forecast the future of quantum information technology [1]. Before that, I just thought of them as a list that I showed in various talks and wrote down in a few essays. So the fact that they have become a “thing” is basically because some government bureaucrats found them a handy way to draw up metrics for the progress of their quantum computing programs.

Continue reading Looking back at the DiVincenzo criteria