Summary
Harvard's Jacob Barandes proposes a new formulation of quantum mechanics called "indivisible stochastic processes," which suggests there is no fundamental wave function and replaces traditional quantum state evolution with sparse, non-Markovian conditional probabilities, aiming to offer a more physical and less ambiguous ontological picture for quantum phenomena.
Key Takeaways
- New Formulation (Indivisible Stochastic Processes): Jacob Barandes's framework postulates that physical systems have definite configurations, but their dynamics are governed by a sparse set of conditional probabilities that are "indivisible" (non-iterative and non-Markovian), meaning the theory does not generally provide transition probabilities or trajectories over intermediate times. 23:59
- Core of Quantum Power: According to Barandes, the power of quantum computers stems from this "indivisibility" of processes, as the class of indivisible processes is larger than those classical computers can use, rather than from parallel universes as suggested by some interpretations. 0:51
- Critique of Many Worlds Interpretation: Scott Aaronson argues that while quantum computation demonstrates a "vastly bigger" reality than classical physics posits, it doesn't necessitate parallel universes, especially since interference effects (crucial for quantum speedups) mean branches haven't fully separated into distinct universes. [4:36] Jacob further critiques Many Worlds for requiring numerous "speculative metaphysical hypotheses" (the "Stone Soup" problem) and for predicting too many bizarre "super maverick branches," making it vacuous (the "Library of Babel" problem). 1:51:11
- Distinction from Bohmian Mechanics: Barandes's theory differs from Bohmian mechanics by getting rid of the wave function in its ontology and, crucially, by not providing calculable trajectories for particles. While trajectories are asserted to exist, the theory does not supply their distribution, making them unknowable in principle by us. 49:24
- Motivation for a New Picture: Barandes seeks to provide a more physically intuitive and less ambiguous picture of quantum mechanics, especially for extreme astrophysical, cosmological, or quantum gravity situations where the standard Dirac-von Neumann axioms become vague or insufficient. 32:41
- Scott's Skepticism on Utility: Scott Aaronson, while open-minded, remains unconvinced, arguing that Barandes's theory (as "Bohm minus minus") asserts unobservable trajectories without offering practical improvements for calculating quantum algorithms or a clearer physical story compared to existing interpretations or standard quantum mechanics. 1:06:15
- Potential for Generalization and Pedagogy: Barandes posits that starting from simpler, fewer axioms phrased in ordinary probability theory allows greater flexibility to generalize quantum theory in ways difficult to imagine from the Hilbert space formulation and could lead to new pedagogical approaches. 1:20:54
