On the status of quantum tunnelling time

Abstract

How long does a quantum particle take to traverse a classically forbidden energy barrier? In other words, what is the correct expression for quantum tunnelling time? This seemingly simple question has inspired widespread debate in the physics literature. I argue that we should not expect the orthodox interpretation of quantum mechanics to provide a unique correct expression for quantum tunnelling time, because to do so it would have to provide a unique correct answer to a question whose assumptions are in tension with its core interpretational commitments. I explain how this conclusion connects to time’s special status in quantum mechanics, the meaningfulness of classically inspired concepts in different interpretations of quantum mechanics, the prospect of constructing experimental tests to distinguish between different interpretations, and the status of weak measurement in resolving questions about the histories of subensembles.

Quantum Measurements and Delays in Scattering by Zero-Range Potentials

“…It is only natural to expect a quantum scattering process, be it collision between two particles or tunnelling across a potential barrier, to be characterised by a particular duration. Discussion about what this duration should be, and how ought to be measured, continues to date [1]. Traditionally, there were two schools of thought.…”