If you’ve ever wondered how an invisibility cloak would work, how to terraform Mars, how to make a forcefield, whether we’re living in a Matrix-like simulation or how far we are from a working teleportation device, Michio Kaku is your man. In books such as Physics of the Impossible, Physics of the Future and Parallel Worlds, Kaku combines the scientific chops of the theoretical physics professor he is with the gee-wow wonder of a sci-fi geek.

His new book, Quantum Supremacy, argues – here I simplify, but not much – that quantum computers are going to be the solution to all mankind’s problems, and that shift from the digital to the quantum age will be a greater leap than the original digital revolution.

‘Everything,’ he says, ‘everything about the economy, medicine, warfare – everything is going to be turned upside down.’ Why? Because quantum computers are unimaginably more powerful than the digital sort.

Digital computers work with ‘bits’, noughts and ones, ‘a very crude approximation of reality’. But quantum computers use the qubit – the state of an atom – as a unit of computation. As we know from quantum theory, atoms can point up or down, but also spin: ‘There are infinitely more states than just zeros and ones… the digital revolution will look like an abacus.’ To give a sense of how fast that scales, in 2019 Google reported that its 53-qubit Sycamore computer could solve in 200 seconds a mathematical problem that would take the fastest digital computer 10,000 years to finish. Last year, IBM unveiled a 433-qubit quantum computer. The 1,121-qubit follow-up is due any day, and it hopes to have a 4,000-qubit version working by 2025.

‘There are infinitely more states than just zeros and ones… the digital revolution will look like an abacus’

So the field is moving fast. Quantum supremacy – the point at which a quantum computer kicks a digital computer’s ass – is in the rear-view mirror. The only problem is that for quantum computers to work, so far, they need to be cooled to very near absolute zero. ‘You have to cool it down to where all the extraneous vibrations and noise are eliminated,’ Kaku explains. ‘Somebody’s burping. Somebody’s jumping up and down. A car backfiring a block away would ruin a quantum calculation.’ A whole range of different approaches are even now competing worldwide to get the edge on making bigger quantum computers faster.

When they get there, though, they will transform everything. Digital computers simply don’t have the capacity to model chemical reactions at the molecular level. Quantum computers will. ‘Chemical reactions are mediated by electrons. Electrons are described by waves. Waves are probability,’ Kaku says. ‘Where are the zeros and ones? Nowhere to be seen. A zero and a one is an approximation, a crude approximation, to a wave. And that wave is the wave of an electron. Why is that important? Because that electron gives you cancer, gives you wellbeing, gives you solar energy, gives you fusion power. Mother Nature is quantum mechanical. The universe is in some sense a quantum compute