Insights into Quantum Time Reversal from the Classical Schrödinger Equation

Craig CallenderUniversity of California, San Diego

Tuesday, October 31, 2023
1:00pm–3:00pm (East Coast time)

[Registration Form] (Abstract and Video Below)

• The Foundations of Physics @Harvard series is co-sponsored by the Department of Philosophy
• This is a free Zoom event (no registration fee)
• The meeting ID and password will be shared with those who register
• Each talk will be 1 hour, followed by a 5-minute break and then 55 minutes for questions
You can find more events in this series in the navigation panel on the left
• You can visit the YouTube channel here

Questions or comments: Jacob Barandes, firstname_lastname(at) (organizer)

Video (YouTube)


Open Discussion and Q&A


The need to implement time reversal via complex conjugation in quantum theory has always been a bit of a puzzle. Why should i go to -i under temporal reflection when it has no spatiotemporal dimensions? In the talk I’ll provide a new explanation. I begin with the little-appreciated fact that classical statistical mechanics has exactly the same issue when it is represented in the “quantum-looking” classical Schrodinger equation of Schiller and Rosen. Since we know what is going on classically, it is possible to extricate ourselves from this puzzle. I then take the classical solution’s counterpart in the quantum context. No doubt this last step will be controversial because it involves invoking an interpretation of quantum theory. If I’m right, the puzzle over time reversal in quantum theory arises because standard quantum mechanics gives us only “half” a theory.