Quantum computing era arrives

""Here, we report using a processor with programmable superconducting qubits to create quantum states on 53 qubits ... 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." .... (original paper here).
Scientists and engineers from Google and NASA Ames Research Center have published a paper (accidentally released and quickly yanked a few weeks ago) that shows they have achieved quantum supremacy, the first goal in a worldwide race to exploit quantum technology for computing, communication, cryptography, materials design, and potentially a lot more.
A normal bit in a computer is either in state value 0 or 1.  The qubit (a photon or electron) can be in any number of states: it's not a 0 or 1 (although it could be) but a matter of probabilities. . One way to look at it is that conventional or "classic" computing is ordinary multiplication and division, while quantum computing is calculus.   The quantum machines on the market now, called quantum annealers, are a kind of hybrid that helps with certain problems, notably optimizations (the classic traveling salesman problem), but on any scale, like the organizing of 5,000 microsatellites for optimal coverage and collision avoidance.  Quantum supremacy means building a computer that solves a problem no conventional computer could do within even the longest of useful time frames. 

Dr. Richard Fenyman was one of those who first laid out the challenge decades ago: “Nature isn’t classical, dammit, and if you want to make a simulation of nature you’d better make it quantum mechanical, and by golly, it’s a wonderful problem because it doesn’t look easy.”

It's not easy.  A true all-purpose quantum computer needs thousands of time as many qubits as the Google making, but what matters is that the concept has been proved. The Google geniuses made a quantum computer that, as noted in the excerpt above, performed in 200 seconds a computation that would have taken a classical computer 10,000 years.  The  uses will come along slowly, not in a flood, and we don't know yet all the uses the computer could - and could not - be used for. 
One of the possible uses, cryptography, is the one that scares everyone.  Encryption is, in its simplest form, done with a numerical key (either identical (symmetrical encryption) or different (asymmetrical encryption) at each end.  Multiplying very large numbers together creates a mess a classical computer has to hack through by trying every possible combination (a " brute force'" attack), and some such encryptions will take the best of super computers millions of years to unravel  A quantum computer, with enough size/power (qubits) and adequate error correction capability (very important with the fragility of qubits) can do it in hours.   Quantum computers can be used both to factor (decrypt) existing codes and to create their own, which in turn will be hard for even quantum computers to decrypt.  
Quantum computers won't replace the ones in your smartphone or laptop: that would be like using a Ferrari engine to power a wagon.  But there's no question we've stepped into a new universe.