The logic of logical qubits

Over the recent years, the focus of QC hardware research has been gradually shifting from building qubits to building logical qubits. It is with some regularity that some press release somewhere announces some first-of-its-kind logical qubit, in a way that can be frankly quite confusing. So in today’s post, we will try to start disentangling this mess by answering the question: what actually is a logical qubit?

Are trapped ions hard to scale?

A common outsider’s view is that trapped-ion QCs are hard to scale. Are they really, and if so, what makes them so?

Tldr: No, I don’t think trapped ions are harder to scale that other types of qubits! In fact, in most cases, the prospect of scaling trapped ion QCs to “proper” large scales seems quite easy compared to most other platforms!

Oppenheimer

I’m probably one of the last physicists out there to do so, but at last, I watched Oppenheimer during the Christmas break. And doing so, invariably, reignited my awe for the Manhattan Project and its leadership.

How to (actually) build a quantum workforce of the future

I dare to guess that these days every other quantum conference features a panel discussion about “tackling the shortage of quantum skills” or “building the quantum industry workforce”. I was pretty interested the first time I heard one, but quickly lost interest since due to excessive fluff-to-ideas ratio (bring back the Big Talk!)

Too many typos for superconductivity?

Over the last week or so, the world of science became enchanted by a pair of obscure preprints claiming the synthesis of the first room-temperature ambient-pressure superconductor LK-99. So far, the story has everything you might want in your Netflix drama: a breakthrough claim, scientific outsiders, sceptical experts, in-fighting among authors, a race to replication, demands for retraction… What time to be alive!

How fast are quantum computers (part 2.5: Terry Rudolph)

A few months back, I wrote a blog post comparing the clock speeds of different quantum computers. In it, I stated that the clock speed of photonic QCs is essentially set by the resource state generation rate. This, I argued, is no small challenge, as the state-of-the-art photonic graph state generation rate is ~ 10 Hz, while PsiQuantum architecture papers assume it to be ~ 1 GHz: that’s 8 OOMs to bridge!

What your papers say about you

The “conventional view” of academia equates researcher’s worth with their publication record. The more “enlightened” among us don’t like that very much, but either accept it as the best out of bad options, or attempt to supplement it with additional metrics, e.g. related to teaching, open-source development, community engagement etc. Both of these views feel quite alien to me.

Trust me, I'm CMOS compatible

One of the challenges of making useful quantum computers is the regular computers are already so goddamn powerful. However you look at it, silicon electronics has had a run unlike anything else. Trilions of dollars were invested to develop trillions of dollars’ worth of capabilities which bring customers trillions of dollars in value.

How fast are quantum computers (part 2: clock speeds)

In the last post, we asked how to quantify the speed of quantum computers.

How fast are quantum computers (part 1)

The point of quantum computers is that, once created, they will solve problems too complex for any present or future supercomputer. To a layperson, this sentence is equivalent to “quantum computers are much faster than any supercomputer will ever be”. This annoys some quantum people because, technically, quantum computers are not fast at all.

Trapped ions: the good and the ugly

It is challenging to form an informed understanding of the quantum computing landscape. For understandable reasons, most scientists avoid dissing their own work, and platform-to-platform comparisons rarely go beyond “trapped ions work well, but are hard to scale”.

Against (most) quantum cryptography

Let me prefix by saying: quantum key distribution - or QKD - is one of the coolest ideas out there. The fact that secrecy can be certified by the laws of physics is truly crazy, and well-deserving of hype and excitement.

Can we forecast the future of quantum computing?

The billion/trillion dollar question: which hardware platform is the right one for quantum computing? This post is about why this question is so hard to answer!

Ion traps you never knew existed

One of the neat things about superconducting qubits is that new qubit types constantly pop up. You have the transmon, xmon, pokemon, fluxonium, quatronium, blochnium… I don’t know what these are, but they do sound high-tech!

How much is 100 qubits?

Writing about D-Wave, Quantum Observer notes:

Welcome

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