Quantum physics is not an easy field to understand, especially with the large number of paradoxes that lie at its heart. Niels Bohr, one of the field’s founders, put it this way: “Those who are not shocked when they first come across quantum theory cannot possibly have understood it.”
The three main problems that make quantum physics “inscrutable,” according to quantum physicist Ruth E. Kastner, are “uncertainty, nonlocality and the measurement problem.”
Or to put it in simpler terms: 1) you cannot know at the same time both the location and speed of quantum particles such as electrons and protons; 2) entangled particles are linked even across vast distances, which conflicts with Einstein’s theory of relativity and the limits of the speed of light; 3) measuring quantum objects affects their state, or the Schrödinger’s cat problem.
To disentangle quantum physics from these paradoxes—by making sense of them all—Kastner calls for a paradigm shift in the field. This requires physicists to think outside the box, with the “box” being space-time itself. This should be easy because according to quantum physics, there is no absolute time or space, and reality extends beyond space-time.
Kastner’s call for a paradigm shift is not new. Werner Heisenberg, another founder of quantum theory, proposed that quantum objects sit in a strange middle ground “between the idea of an event and the actual event.”
Kastner says that the secret to understanding the paradoxical aspects of quantum physics is by applying Heisenberg’s idea to what’s known as the transactional interpretation (TI) of quantum mechanics.
This theory suggests that quantum states can be both absorbed and emitted. A transaction—which is equivalent to the “collapse of a quantum state”—occurs between the emitter and the absorber. This is what leads to a “measurement” in quantum physics.
According to the new version of T1 (what Kastner is calling the “possibilist TI” or PTI), the “offer” of the emitter and the “confirmation” of the absorber are only possibilities that exist outside ordinary space-time. When these transactions occur, however, the quantum possibilities collapse into the concrete events that we see in space-time.
As Kastner says: “So, collapse is not something that happens anywhere in space-time. It is the creation of space-time itself.”
It’s for this reason that Schrödinger’s cat doesn’t remain in a superposition of alive and dead after we open its box. Kastner hopes that this approach will also clarify the other paradoxes that have plagued quantum physics since its inception.