# Quantum Physics Probabilistic Foundations Face New Mathematical Scrutiny Recent analysis suggests deriving the Born rule from deterministic principles remains elusive for physicists. - **Source:** [New Scientist](https://www.newscientist.com/) - **Published:** 2026-10-29 - **Topic:** [Business](https://brifing.si/c/business) - **Original article:** - **On Brifing:** https://brifing.si/s/18209934-e589-417e-aff7-00582ab8911a ## The Persistent Measurement Problem Quantum mechanics remains defined by its probabilistic nature, famously illustrated by Schrödinger’s cat thought experiment. Objects exist in mutually exclusive states until observed, causing an abrupt reduction to a single outcome. This measurement problem represents one of the most significant unresolved questions in modern physics, challenging our fundamental understanding of reality. ## Role of the Born Rule The Born rule serves as a mathematical recipe for converting quantum information into observable probabilities. Originally a postulate, it forces physicists to accept that quantum mechanics cannot provide firm outcomes, only likelihoods. Researchers have long sought to derive this rule from deterministic mathematical ingredients to remove inherent probabilistic oddness from theory. ## Zhang's Analytical Methodology Jiaxuan Zhang from the University of Oxford spent two years examining five influential derivations of the Born rule. By maintaining an interpretation-agnostic stance, she focused exclusively on the underlying mathematics rather than theoretical interpretations. Her goal was to determine if past efforts inadvertently introduced probabilistic ingredients at the very starting point. ## The Necessity of Additivity Zhang concluded that a concept known as additivity is indispensable to all analyzed derivations of the Born rule. Similar to how probabilities of rolling fair dice must sum to 100 percent, additivity remains a core requirement. Her findings suggest that current attempts to build quantum mechanics on purely deterministic foundations remain unsupported. ## Expert Perspective on Findings Augusto Smerzi of Shenzhen Technology University notes that Zhang’s work brings necessary clarity to a long-standing problem. By explicitly identifying the assumptions required for the Born rule, she highlights where the mathematical logic relies on probability. This transparency is essential for evaluating the validity of existing quantum mechanical frameworks and theories. ## Beyond Mathematical Assumptions Smerzi emphasizes that identifying assumptions does not explain why nature obeys the Born rule so accurately. While making these assumptions explicit is a critical step, the deeper physical meaning remains hidden. The research does not close the door on future explanations but instead clarifies the boundaries of our current mathematical understanding. ## Future Research Trajectories Zhang plans to expand her analysis to include additional derivations of the Born rule beyond the initial five. She acknowledges that the work is far from complete and mathematical surprises may still exist. While her current results constrict possibilities, a small chance remains that deterministic foundations could eventually be successfully established. ## Implications for Quantum Foundations The quest to ground quantum mechanics in deterministic principles continues to drive theoretical physics forward. By rigorously testing the origins of quantum probability, researchers like Zhang are narrowing the scope of potential solutions. This ongoing scrutiny is vital for eventually uncovering the deeper origins of the universe's most puzzling quantum behaviors. ## Sources covering this story - https://www.newscientist.com/article/2596105-key-oddity-of-quantum-physics-may-run-even-deeper-than-anticipated/?utm_campaign=RSS|NSNS&utm_content=home&utm_medium=RSS&utm_source=NSNS — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._