English

Wigner rotations and an apparent paradox in relativistic quantum information

Quantum Physics 2017-07-04 v2

Abstract

It is shown that a general model for particle detection in combination with a linear application of the Wigner rotations, which correspond to momentum-dependent changes of the particle spin under Lorentz transformations, to the state of a massive relativistic particle in a superposition of two counter-propagating momentum states leads to a paradox. The paradoxical behavior is that the probability of finding the particle at different positions would depend on the reference frame. A solution to the paradox is given when the physical construction of the corresponding state is taken into account, suggesting that we cannot in general linearly apply the Wigner rotations to a quantum state without considering the appropriate physical interpretation.

Keywords

Cite

@article{arxiv.1303.4367,
  title  = {Wigner rotations and an apparent paradox in relativistic quantum information},
  author = {Pablo L. Saldanha and Vlatko Vedral},
  journal= {arXiv preprint arXiv:1303.4367},
  year   = {2017}
}

Comments

5 pages, 2 figures. We changed the example used to show that the linear application of the Wigner rotations to the state of a massive relativistic particle in a superposition of two counter-propagating momentum states leads to a paradox. There was a problem with the example used in the previous version