Multiphoton states related via linear optics Articles uri icon

authors

  • MIGDAL, PIOTR
  • RODRIGUEZ LAGUNA, JAVIER
  • OSZMANIEC, MICHAL
  • LEWENSTEIN, MACIEJ

publication date

  • June 2014

issue

  • 6

volume

  • 89

International Standard Serial Number (ISSN)

  • 1050-2947

Electronic International Standard Serial Number (EISSN)

  • 1094-1622

abstract

  • We investigate which pure states of n photons in d modes can be transformed into each other via passive linear optics, without postselection. In other words, we study the local unitary (LU) equivalence classes of symmetric many-qudit states. Writing our state as f†|Omega, with f† a homogeneous polynomial in the mode creation operators, we propose two sets of LU invariants: spectral invariants, which are the eigenvalues of the operator ff†, and moments, each given by the norm of the symmetric component of a tensor power of the initial state, which can be computed as vacuum expectation values of fk(f†)k. We provide a scheme for experimental measurement of the later, as related to the postselection probability of creating state f†k|Omegafrom k copies of f†|Omega. © 2014 American Physical Society.

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