Grasping Reality on TypePad, by Brad DeLong

*John Preskill *: Explains ‘Quantum Supremacy’ https://www.quantamagazine.org/john-preskill-explains-quantum-supremacy-20191002/: 'In the 2012 paper that introduced the term “quantum supremacy,” I wondered: “Is controlling large-scale quantum systems merely really, really hard, or is it ridiculously hard? In the former case we might succeed in building large-scale quantum computers after a few decades of very hard work. In the latter case we might not succeed for centuries, if ever.” The recent achievement by the Google team bolsters our confidence that quantum computing is merely really, really hard. If that’s true, a plethora of quantum technologies are likely to blossom in the decades ahead...