Abstract
Detecting and quantifying quantum entanglement of a given unknown state poses problems that are fundamentally important for quantum information processing. Surprisingly, no direct (i.e., without quantum tomography) universal experimental implementation of a necessary and sufficient test of entanglement has been designed even for a general two-qubit state. Here we propose an experimental method for detecting a collective universal witness, which is a necessary and sufficient test of two-photon polarization entanglement. It allows us to detect entanglement for any two-qubit mixed state and to establish tight upper and lower bounds on its amount. A different element of this method is the sequential character of its main components, which allows us to obtain relatively complicated information about quantum correlations with the help of simple linear-optical elements. As such, this proposal realizes a universal two-qubit entanglement test within the present state of the art of quantum optics. We show the optimality of our setup with respect to the minimal number of measured quantities.
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Full text
- Publication version
- Accepted or Published Version
- DOI:
- Digital Object Identifier (open in new tab) 10.1103/PhysRevA.91.032315
- License
- Copyright (2015 American Physical Society)
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Details
- Category:
- Articles
- Type:
- artykuł w czasopiśmie wyróżnionym w JCR
- Published in:
-
PHYSICAL REVIEW A
no. 91,
edition 3,
pages 1 - 7,
ISSN: 2469-9926 - Language:
- English
- Publication year:
- 2015
- Bibliographic description:
- Bartkiewicz K., Horodecki P., Lemr K., Miranowicz A., Życzkowski K.: Method for universal detection of two-photon polarization entanglement// PHYSICAL REVIEW A. -Vol. 91, iss. 3 (2015), s.1-7
- DOI:
- Digital Object Identifier (open in new tab) 10.1103/physreva.91.032315
- Verified by:
- Gdańsk University of Technology
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