Let’s start with applications. A protocol that I came up with a couple years ago uses a sampling process, just like in Google’s quantum supremacy experiment, to generate random bits. ... Google is now working toward demonstrating my protocol; it bought the non-exclusive intellectual property rights last year.He was the outside reviewer of the Google paper published in Nature. So he had a big hand in the editorial decision to say that this was quantum supremacy. Aaronson claims the credit for Google confirming that quantum computers can be used for generating random numbers. And Google paid Aaronson for the privilege.
I am not accusing Aaronson of being crooked here. I sure his motives are as pure as Ivory Soap. But he sure has a lot invested in affirming quantum supremacy based on random number generation. Maybe the Nature journal should have also required this disclosure.
The computer revolution was enabled, in large part, by a single invention: the transistor. ... We don’t yet have the quantum computing version of the transistor — that would be quantum error correction.So we don't have real qubits yet.
Aaronson has spent many years trying to convince everyone that there is a right way and a wrong way to explain qubits. Here is the wrong way:
For a moment — a few tens of millionths of a second — this makes the energy levels behave as quantum bits or “qubits,” entities that can be in so-called superpositions of the 0 and 1 states.So here is his better version:
This is the part that’s famously hard to explain. Many writers fall back on boilerplate that makes physicists howl in agony: “imagine a qubit as just a bit that can be both 0 and 1 at the same time, exploring both possibilities simultaneously.”
Here’s a short version: In everyday life, the probability of an event can range only from 0 percent to 100 percent (there’s a reason you never hear about a negative 30 percent chance of rain). But the building blocks of the world, like electrons and photons, obey different, alien rules of probability, involving numbers — the amplitudes — that can be positive, negative, or even complex (involving the square root of -1). Furthermore, if an event — say, a photon hitting a certain spot on a screen — could happen one way with positive amplitude and another way with negative amplitude, the two possibilities can cancel, so that the total amplitude is zero and the event never happens at all. This is “quantum interference,” and is behind everything else you’ve ever heard about the weirdness of the quantum world.Really? I may be dense, but I don't see that this is any better. He insists that the key is realizing that probabilities can be negative, or imaginary.
But this is just nonsense. There are no negative probabilities in quantum mechanics, or anywhere else.
We do have interference. Light does show interference patterns, as is possible for all waves. There is nothing the slightest bit strange about waves showing interference. But Aaronson insists on saying that the interference comes from negative probabilities. I don't see how that is mathematically accurate, or helpful to understanding quantum mechanics.