Abstract Objections to pilot-wave theory frequently come in three mutually-contradictory categories: that the theory is too bizarrely different from ordinary physics, that the theory is not radically different enough, and that the physics of pilot-wave theory is after all just the same as quantum physics. After a brief review of pilot-wave theory, we critically evaluate these objections. We show how the radical nature of pilot-wave theory is often misunderstood or overlooked. We highlight the novelty of its dynamics, and clarify its implications for our understanding of measurement, as well as discussing the status of Lorentz invariance, conservation laws, and the Born rule. We examine Einstein’s early work on pilot-wave theory and argue that he turned away from it for reasons which are no longer compelling. We urge that the theory be understood on its own terms, as a generalised nonequilibrium theory empirically distinct from quantum mechanics, with all its potentially revolutionary implications
Abstract Objections to pilot-wave theory frequently come in three mutually-contradictory categories: that the theory is too bizarrely different from ordinary physics, that the theory is not radically different enough, and that the physics of pilot-wave theory is after all just the same as quantum physics. After a brief review of pilot-wave theory, we critically evaluate these objections. We show how the radical nature of pilot-wave theory is often misunderstood or overlooked. We highlight the novelty of its dynamics, and clarify its implications for our understanding of measurement, as well as discussing the status of Lorentz invariance, conservation laws, and the Born rule. We examine Einstein’s early work on pilot-wave theory and argue that he turned away from it for reasons which are no longer compelling. We urge that the theory be understood on its own terms, as a generalised nonequilibrium theory empirically distinct from quantum mechanics, with all its potentially revolutionary implications
Quantum theory and the de Broglie – Bohm pilot-wave theory are empirically equivalent. In addition to other objections to the pilot-wave theory, many physicists (and some philosophers) take this to be enough to dismiss the pilot-wave theory, as they say it adds nothing to the standard theory. In this short paper I review some objections and replies to the pilot-wave theory. In particular I respond to the empirical equivalence challenge arguing that, given their mutual relationship, there is no reason to expect the two theories to make different predictions, even if they actually might.
Tim Maudlin has argued that the standard formulation of quantum mechanics fails to provide a clear ontology and dynamics and that the de Broglie--Bohm pilot-wave theory offers a better completion of the formalism, more in line with Einstein's concerns. I suggest that while Bohmian mechanics improves on textbook quantum theory, it does not go far enough. In particular, it relies on the ``quantum equilibrium hypothesis'' and accepts explicit nonlocality as fundamental. A deeper completion is available in stochastic mechanics, where the wavefunction and the Born rule emerge from an underlying diffusion process, and in a contextual, category-theoretic semantics in which measurement and EPR--Bell correlations are reinterpreted as features of contextual truth rather than of mysterious dynamics. In this framework, the measurement problem and ``spooky action-at-a-distance'' are dissolved rather than solved. Finally, a dynamics based on Rosen's ``classical Schrödinger equation'' provides a continuous passage between quantum and classical regimes, eliminating any sharp Heisenberg cut.
We show how pilot-wave theory points to new physics, beyond quantum mechanics, in three distinct ways. First, generalised cosmological initial conditions, departing from the Born rule, can lead to observable anomalies in the cosmic microwave background and in relic cosmological particles. Second, a breakdown of the Born rule in the deep quantum-gravity regime, with gravitational corrections that render the Born rule semiclassically unstable, can create anomalies in Hawking radiation from evaporating black holes. Third, a regularised equation of motion that remains finite at nodes of the wave function generates corrections to the Born rule at short distances, while a natural time-dependent generalisation implies an instability of quantum equilibrium at short times, effects which may be observable in high-energy collisions.
Abstract Beyond the Quantum 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.
Abstract ‘Origins of Pilot-Wave Theory’ delves into the historical origins of pilot-wave theory and clarifies many of the misunderstandings surrounding it. We begin with an account of Louis de Broglie’s work in the 1920s, including his lecture at the famous but widely misunderstood 1927 Solvay conference. We show how this troubled theory has been repeatedly dismissed and frequently misrepresented. We describe the rise of the notorious measurement problem, the widespread confusion about the nature of probability in pilot-wave theory, as well as attempts to associate the theory with mysticism and the paranormal. The chapter ends with a careful assessment of the scientific evidence for nonlocality (action at a distance), in the form of measured violations of Bell’s inequality.
The de Broglie-Bohm pilot-wave theory promises not only a realistic description of the microscopic world (in particular, a description in which observers and observation play no fundamental role) but also the ability to derive and explain aspects of the quantum formalism that are, instead, (awkwardly and problematically) postulated in orthodox versions of quantum theory. Chief among these are the various "measurement axioms" and in particular the Born rule expressing the probability distribution of measurement outcomes. Compared to other candidate non-orthodox quantum theories, the pilot-wave theory suffers from something of an embarrassment of riches in regard to explaining the Born rule statistics, in the sense that there exist, in the literature, not just one but two rather compelling proposed explanations. This paper is an attempt to critically review and clarify these two competing arguments. We summarize both arguments and also survey some objections that have been given against them. In the end, we suggest that there is somewhat less conflict between the two approaches than existing polemics might suggest, and that indeed elements from both arguments may be combined to provide a unified and fully-compelling explanation, from the postulated dynamical first principles, of the Born rule.