Based on decades of research, this book offers a panoramic rethink of quantum physics, with potentially revolutionary implications for cosmology, quantum gravity, and quantum technology. Properly understood, 'pilot-wave theory' provides a deeper foundation for quantum mechanics, while also going beyond it. First proposed in the 1920s by French aristocrat and physicist Louis de Broglie, and revived in the 1950s by American physicist David Bohm, the theory posits hidden particle motions we cannot currently see or control. The theory is usually regarded as merely an alternative account of the same physics we already know. In fact, pilot-wave theory implies a wealth of new and radical physics beyond the reach of quantum mechanics. Pilot-wave theory tells us that quantum physics is a special case of something broader and deeper. In more general 'nonequilibrium' conditions, Einstein's relativity and Heisenberg's uncertainty break down. Superluminal signalling becomes possible, and quantum particles can be clearly seen and controlled. This new physics could have left traces in the early universe, and it might be visible today in radiation from exploding primordial black holes. Harnessing this new physics would have transformative technological implications, in particular for communication, cryptography, and computing. Drawing intriguing parallels between the present era of quantum physics and past episodes of scientific confusion, this book tells the story of how pilot-wave theory was discovered and abandoned, revived and reconstructed, and how today it can pave the way to a new and radical physics beyond the quantum.

A fascinating exploration of a beautiful hypothesis about the mysteries of quantum phenomena, by an independent, careful, and courageous thinker * Carlo Rovelli, Aix-Marseille University, author of Seven Brief Lessons on Physics and The Order of Time *
Written with great clarity and elegance; and with a gift for vivid - but always appropriate and didactically helpful - metaphors * Jeremy Butterfield, Senior Research Fellow, University of Cambridge *
This is the best book yet written in this century to understand the great debate now raging among today's physicists and philosophers. On one side stand the antirealists, arguing we must reject the notion that science tells us what is real. Valentini stands as the most important thinker of this century defending the notion that science gives a complete description of physical processes. With crystal clear prose and brilliant pedagogy Valentini guides us along a trip to understand how quantum theory may be saved. * Lee Smolin, Perimeter Institute for Theoretical Physics, author of The Trouble with Physics and Einstein's Unfinished Revolution. *
a remarkable new book reminds us what a big idea really looks like * New Scientist *

Antony Valentini graduated from Cambridge University and obtained his PhD at the International School for Advanced Studies. He has held research positions at the University of Rome La Sapienza, Imperial College London, and Perimeter Institute for Theoretical Physics. He was Professor of Physics at Clemson University and is an Academic Visitor at Imperial College London. He is co-author of Quantum Theory at the Crossroads (Cambridge University Press, 2009).