# Where Photons Have Been: Nowhere Without All Components of Their Wavefunctions

## TL;DR

This paper analyzes a photon experiment and evaluates quantum interpretations to explain where photons have been.

## Contribution

It demonstrates that the Transactional Interpretation explains observed phenomena better than the Two-State Vector Formalism.

## Key findings

- The TSVF fails to predict data using only first-order wavefunction components.
- The Transactional Interpretation successfully accounts for all observed phenomena.
- The experiment supports time-symmetric interpretations of quantum theory.

## Abstract

A nested interferometer experiment by Danan et al. is discussed and some claims are evaluated concerning the whereabouts of the photon, primarily within the context of time-symmetric interpretations of quantum theory, including the Two-State Vector Formalism (TSVF) and the Transactional Interpretation (TI). It is pointed out that the TSVF account fails to predict the observed data based only on the first-order wavefunction component. It is shown that the Transactional Interpretation readily accounts for all the observed phenomena.