Now You're Computing With Molecules
Two teams of physicists have reported trapping molecules in laser light and putting them in a quantum entangled state. It's an important step forward into making quantum computers out of neutral molecules instead of ions.
To explain why that (may) matter, let's talk about quantum computers. Traditional computers manipulate bits, values that are either 0 or 1, using deterministic operations. Given the same input, you get the same output every time. Quantum computers, however, take advantage of the probabilistic nature of quantum mechanics. They use qubits, which can be a little bit 0 and a little bit 1. They're in a superposition of the two values. Before you look at the qubit, you can't know what its value truly is. When you do look at it, it'll either be 0 or 1 with a certain probability.
That doesn't sound useful! Who wants a computer whose answers you can't depend on? You have to find a way to amplify the answer you want so that you're likely to get the right answer from the quantum computer. It's a pain, and the range of problems you can tackle this way is much smaller than what you can do with classical computers.
It can still be worth it, though, because of entanglement, another quantum mechanical effect. You can link multiple qubits together so that what happens to one of them affects the others. Entangling multiple superposed qubits lets you pack in way more information than traditional bits. Three classical bits give you three units of information. Three qubits give you eight units of information. In math terms, n entangled qubits gives you 2n units of information. Anything a quantum computer can do, a classical computer can, too, but the quantum computer may be able to do it much faster in part because its information density is so much greater. When you manipulate a qubit, you're affecting way more information at the same time.
For most problems you'd solve using a computer, the quantum approach isn't better, if it's possible at all. Most of these quantum algorithms solve problems or simulate systems that only scientists care about. Then there's Shor's algorithm for quickly factoring integers.
When Peter Shor came up with his eponymous algorithm in 1994, folks got very interested in quantum computers. If you can factor integers quickly, you can break public-key cryptography. And if you break public-key cryptography, you'll break the internet. You'd be able to snoop on people's web traffic. The schemes that keep your password safe when you log into your bank's website? That uses public-key cryptography. The world might end!!!
Shor's discovery supercharged the development of quantum computers and spawned endless thinkpieces about the end of the internet. In 2001, an IBM group factored the number 15 into 3 and 5. By 2019 we almost factored the number 35. Thirty years on, we're still getting breathless articles about how we're about to break the internet using quantum computers, but the results are still underwhelming. What happened?
Quantum computers turned out to be hard to build. Quantum entanglement works until the atoms or molecules you're using for qubits interact with anything that's not another qubit. You get quantum decoherence, smearing out the quantum mechanical effects. You have to keep your quantum computer ultra-cold and ultra-isolated to keep the qubits entangled.
One way to build a quantum computer is to use ions as your qubits. Strip electrons off of atoms so that they have an electric charge, capture them in a magnetic field, and hit them with a laser to entangle them. You can't pack them close together because, like the north end of two bar magnets, their electrical charge repel each other. But it's harder to trap and confine neutral atoms than charged ones.
Harder, but not impossible. If you focus a high-powered laser beam to a small point, you create optical tweezers. Even neutral atoms are attracted to the laser beam's focus. That's what the two groups used to trap two neutral molecules and create a two-qubit system.
Though it's a neat result, I'd temper expectations. Significant engineering challenges stand between these toy systems and a full-scale molecule-based quantum computer. I don't expect quantum computers to take over the world any time soon.
What's Up With Stephen?
We're halfway through year one of Small Wonders, the speculative flash fiction and poetry magazine I co-edit. I'd love for you to subscribe, which gets you each story or poem in your inbox plus collected as an ebook. If you haven't been reading it, here's some pieces to give you a feel for the magazine's vibes:
Imagine Yourself Happy, Premee Mohamed's story about aliens and scientific accidents.
Kodakromen, Elizabeth R. McClellan's poem on pictures and death.
Katya's Microscope, Monica Joyce Evans's new take on a very old horror creature.
Five Easy Hairstyles for Snake-Haired Girls, Jelena Dunato's poem about Medusa's hairstyles.
In other news, I've signed a contract for my short story about uploaded humans wrestling with gender during the singularity. I'm excited for you to get to read it in Inclusive Future Magazine!
What I'm Vibing With
Authors, kindly do not review-bomb other authors on Goodreads.
As someone who does image processing and machine learning for a living, I'm begging you not to trust Tesla's "self-driving" systems.
Couch to Eras Tour, a Taylor Swift themed running program to train to run the entire length of the Eras Tour setlist.
The Verge's four articles eulogizing Twitter are well worth your time.
Video game companies are laying off disastrous numbers of people, E3 is dead, and this year's The Game Awards didn't go great.
This comfy rat makes me miss our two rats so bad.
Finally, Feferi, our new Corgi puppy, and Anwen, our old dog, have reached détente.
