Experimental witnessing of the quantum channel capacity in the presence of correlated noise
Authors: Cimini V., Gianani I., Sacchi MF., Macchiavello C., Barbieri Ma
Autors Affiliation: Univ Roma Tre, Dipartimento Sci, Via Vasca Navale 84, I-00146 Rome, Italy; Sapienza Univ Roma, Dipartimento Fis, Piazzale Aldo Moro 5, I-00185 Rome, Italy; CNR, Ist Foton & Nanotecnol, Piazza Leonardo Da Vinci 32, I-20133 Milan, Italy; Univ Pavia, Dipartimento Fis, QUIT Grp, Via A Bassi 6, I-27100 Pavia, Italy; Ist Nazl Fis Nucl, Sez Pavia, Via Bassi 6, I-27100 Pavia, Italy; CNR, Ist Nazl Ott, Largo Enrico Fermi 6, I-50125 Florence, Italy
Abstract: We present an experimental method to detect lower bounds to the quantum capacity of two-qubit communication channels. We consider an implementation with polarization degrees of freedom of two photons and report on the efficiency of such a method in the presence of correlated noise for varying values of the correlation strength. The procedure is based on the generation of separable states of two qubits and local measurements at the output. We also compare the performance of the correlated two-qubit channel with the single-qubit channels corresponding to the partial trace on each of the subsystems, thus showing the beneficial effect of properly taking into account correlations to achieve a larger quantum capacity.
Journal/Review: PHYSICAL REVIEW A
Volume: 102 (5) Pages from: 052404 to: 052404
KeyWords: two-qubit communication channels, noiceDOI: 10.1103/PhysRevA.102.052404