## Increasing relative nonclassicality quantified by standard entanglement potentials by dissipation and unbalanced beam splitting

### Authors:

- Adam Miranowicz,
- Karol Bartkiewicz,
- Neill Lambert,
- Yueh-Nan Chen,
- Franco Nori

### Abstract

If a single-mode nonclassical light is combined with the vacuum on a beam splitter, then the output state is entangled. As proposed in [Phys. Rev. Lett. 94, 173602 (2005)PRLTAO0031-900710.1103/PhysRevLett.94.173602], by measuring this output-state entanglement for a balanced lossless beam splitter, one can quantify the input-state nonclassicality. These measures of nonclassicality (referred to as entanglement potentials) can be based, in principle, on various entanglement measures, leading to the negativity (NP) and concurrence (CP) potentials, and the potential for the relative entropy of entanglement (REEP). We search for the maximal relative nonclassicality, which can be achieved by comparing two entanglement measures for (i) arbitrary two-qubit states and (ii) those which can be generated from a photon-number qubit via a balanced lossless beam splitter, where the qubit basis states are the vacuum and single-photon states. Surprisingly, we find that the maximal relative nonclassicality, measured by the REEP for a given value of the NP, can be increased (if NP<0.527) by using either a tunable beam splitter or by amplitude damping of the output state of the balanced beam splitter. We also show that the maximal relative nonclassicality, measured by the NP for a given value of the REEP, can be increased by phase damping (dephasing). Note that the entanglement itself is not increased by these losses (since they act locally), but the possible ratios of different measures are affected. Moreover, we show that partially dephased states can be more nonclassical than both pure states and completely dephased states, by comparing the NP for a given value of the REEP. Thus, one can conclude that not all standard entanglement measures can be used as entanglement potentials. Alternatively, one can infer that a single balanced lossless beam splitter is not always transferring the whole nonclassicality of its input state into the entanglement of its output modes. The application of a lossy beam splitter can solve this problem, at least for the cases analyzed in this paper.

- Record ID
- UAM23491f5e40594d38aa1050e380c582f0
- Author
- Journal series
- Physical Review A, ISSN 1050-2947
- Issue year
- 2015
- Vol
- 92
- ASJC Classification
- DOI
- DOI:10.1103/PhysRevA.92.062314 opening in a new tab
- Language
- en English
- Score (nominal)
- 35
- Score source
- journalList
- Score
- Publication indicators
- = 15.000; = 19.000; : 2015 = 1.008; : 2018 = 2.907 (2) - 2018=2.723 (5)

- Uniform Resource Identifier
- https://researchportal.amu.edu.pl/info/article/UAM23491f5e40594d38aa1050e380c582f0/

* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perishopening in a new tab system.

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