World's First Programmable Quantum Photonic Chip

MrSeb writes "A team of engineering geniuses from the University of Bristol, England has developed the world's first re-programmable, multi-purpose quantum photonic computer chip that relies on quantum entanglement to perform calculations. With multiple waveguide channels (made from standard silicon dioxide), and eight electrodes, the silicon chip is capable of repeatedly entangling photons. Depending on how the electrodes are programmed, different quantum states can be produced. The end result is two qubits that can be used to perform quantum computing. Most importantly, though, unlike existing quantum photonic setups which require apparatus the size of a 'large dining table,' this new chip is tiny: just 70mm (2.7 inches) by 3mm."

Comments

computing power scales exponentially

[Janek Kozicki]

For those who are unaware why qubits are so powerful: the computing power provided by qubits scales exponentially if compared to bits used in ordinary computing. For example if you had 20 qubits, that would be like doing simultaneous calculations on processor with internal register size of 1048576 bits. Roughly. That's orders of magnitude more than modern CPUs, which have about dozen of 64 bit registers.

Re:computing power scales exponentially

[vlm]

I think he made it up. I am not making up (but could be completely wrong) that coincidentally the difficulty of preventing decoherence scales exponentially. And that is the primary limiter to # of qubits and performance, more or less correct?

In the very long run, I think quantum computing is going to be very much like DSP, in that the "hard work" is handling the analog signals to get "the problem" in and out. Inside ye olde DSP processor, a couple gnomes magically make it work, and superficially seem to be the hard part, at least partially correctly as some of the math is hideous. But the real problem is the unavoidable analog/RF work.

Kind of like how supercomputing is defined as taking a CPU bound process and making it an IO bound process, more or less.

Re:computing power scales exponentially

[alexgieg]

I know qubits can be very useful at encryption/decryption/cracking and such, but I'm curious: what else would they be useful for? I mean, is there something that a typical desktop/workstation does today that could be improved by adding some qubit-based magic behind the scenes, similar to how GPUs (and FPUs before them) resulted in improved GUIs, games, CAD/CAM etc.? Or is this the kind of thing that's most probably going to remain restricted to specific fields, with very specific needs, for the foreseeable future?

Re:computing power scales exponentially

[whovian]

I wonder if it could be used for simulating consciousness. I mean, IBM's Watson is a machine with clever brute force implementation of language parsing and data retrieval. Quantum computing seems paradigm-shifting enough to effectively implement many Watson-type machines, perhaps.

Re:excellent.

[mikael]

That would be awesome to see - a hammock made of woven cat-5 cables.

Once saw the interconnect of a supercomputer/rack server "styled" into ocean waves, rather than just some snake-pit of cables.

Bad news for crypto

[gillbates]

If what you say is true, this is truly bad news for cryptography. Algorithms like AES owe their security largely to the fact that brute-forcing all of the keys is generally impractical; with a 256 qubit machine, AES 256 would be cracked in *a single clock cycle*.

If they can do this with two qubits, why not 4? Why not 8, or 128, or 512?

In the same way the WWII cipher designers probably had a hard time imagining that in 40 years there would exist a machine which could crack their ciphers in real time, the designers of block ciphers like DES and AES probably had a difficult time imagining that their ciphers would be insecure in mere decades. DES took 30 years before brute force became practical; will AES survive even 20?

It was just 20 years from the invention of the transistor to the first 32 bit computer. How long will it be before a machine with more computing power than in all of recorded history can be built on something the size of a postage stamp, for a few dollars?