Quantum Supremacy

Last year's new years predictions blog included achieving Quantum Supremacy at #3. Google’s official paper on Quantum Supremacy was published in October and is available online.

The quantum supremacy experiment pits NASA’s supercomputer, the fastest on Earth and nearly twice the speed of the next most powerful supercomputer, against Google’s Quantum Computer. Surprisingly efficient at only 13 Megawatts of energy to operate, the NASA supercomputer could otherwise power roughly 15,000 homes. Google’s Quantum Computer is the underdog by a good margin going into this battle so beating the supercomputer by any fraction of time is a huge achievement. The MIT Technology Review published a great summary of the experiment in September.

While our processor takes about 200 seconds to sample one instance of the quantum circuit 1 million times, a state-of-the-art supercomputer would require approximately 10,000 years to perform the equivalent task.

The results are actually mind blowing! There really is no relative comparison between 200 seconds and 10,000 years. The quantum computer obliterated the super computer.

Obviously there are barriers to overcome before quantum computers hit the mainstream. For one, they currently operate at extremely low temperatures though recent work on stabilizing qubits at room temperature could solve this issue soon. Quantum computers can also be prone to errors but the reality is so are traditional processors. Modern processors operate at 7 nanometers, the problem appears to be related to quantum tunneling which affects traditional and quantum processors equally.

Further reading:

Scott Aaronson published a very thorough FAQ on his blog on the subject of quantum supremacy that does a great job of building the foundational knowledge about which you may now be very curious.

Implications for Cryptography

We expect their computational power will continue to grow at a double exponential rate: the classical cost of simulating a quantum circuit increases exponentially with computational volume, and hardware improvements will likely follow a quantum-processor equivalent of Moore’s law [52, 53], doubling this computational volume every few years.

If quantum supremacy is so close and barriers to mainstream adoption are starting to topple, all the timelines we take for granted with respect to breaking cryptographic systems disintegrate. Research on post-quantum cryptography is well underway as NIST seeks to select new standards.