Lev Vaidman — Summary

Lev Vaidman (born 4 September 1955) is a Russian-Israeli physicist and professor at Tel Aviv University, noted for theoretical work in fundamentals of quantum mechanics: quantum teleportation, the Elitzur-Vaidman bomb tester (interaction-free measurement), and weak values.

Career

Attended the 45th Physics-Mathematics School in Saint Petersburg; twice All-Soviet Physics Olympiad winner (1st place 1971, 2nd 1972); 26th in International Physics Olympiad (Bucharest, 1972). Emigrated to Israel at 18. Editor of the SEP entry on the Many-Worlds Interpretation of Quantum Mechanics (2002-2026). The Elitzur-Vaidman bomb tester was chosen as one of the “Seven Wonders of the Quantum World” by New Scientist (2010).

Contributions to MWI

• Formalized the measure of existence of a world (mu_i = |alpha_i|
• Introduced self-location ignorance probability (post-measurement uncertainty; sleeping pill experiment) to explain the illusion of probability in the MWI.
• Probability Postulate (Born-Vaidman rule): subjective probability proportional to total measure of existence of worlds with that outcome.
• Behavior Principle: we care about all our successive worlds in proportion to their measures of existence.
• Argues MWI avoids action at a distance; nonlocal correlations explained by nonlocality (nonseparability) of worlds.
• Elitzur-Vaidman interaction-free measurement demonstrates how MWI dissolves paradoxes (from the perspective of the whole Universe).