Quantum storage of polarization qubits in birefringent and anisotropically absorbing materials

Storage of quantum information encoded into true single photons is an essential constituent of long-distance quantum communication based on quantum repeaters and of optical quantum information processing. The storage of photonic polarization qubits is, however, complicated by the fact that many materials are birefringent and have polarization-dependent absorption. Here we present and demonstrate a simple scheme that allows compensating for these polarization effects. The scheme is demonstrated using a solid-state quantum memory implemented with an ensemble of rare-earth ions doped into a biaxial yttrium orthosilicate ($Y_2SiO_5$) crystal. Heralded single photons generated from a filtered spontaneous parametric downconversion source are stored, and quantum state tomography of the retrieved polarization state reveals an average fidelity of $97.5 \pm 0.4$, which is significantly higher than what is achievable with a measure-and-prepare strategy.Comment: 7 pages, 3 figures, 1 table, corrected typos and added ref. 3

Photonic quantum state transfer between a cold atomic gas and a crystal

Interfacing fundamentally different quantum systems is key to build future hybrid quantum networks. Such heterogeneous networks offer superior capabilities compared to their homogeneous counterparts as they merge individual advantages of disparate quantum nodes in a single network architecture. However, only very few investigations on optical hybrid-interconnections have been carried out due to the high fundamental and technological challenges, which involve e.g. wavelength and bandwidth matching of the interfacing photons. Here we report the first optical quantum interconnection between two disparate matter quantum systems with photon storage capabilities. We show that a quantum state can be faithfully transferred between a cold atomic ensemble and a rare-earth doped crystal via a single photon at telecommunication wavelength, using cascaded quantum frequency conversion. We first demonstrate that quantum correlations between a photon and a single collective spin excitation in the cold atomic ensemble can be transferred onto the solid-state system. We also show that single-photon time-bin qubits generated in the cold atomic ensemble can be converted, stored and retrieved from the crystal with a conditional qubit fidelity of more than $85\%$. Our results open prospects to optically connect quantum nodes with different capabilities and represent an important step towards the realization of large-scale hybrid quantum networks

Altitude variation in the composition of essential oils, fatty acid methyl esters, and antimicrobial activities of two subspecies of primula vulgaris grown in Turkey

In this study, the changes caused by variation of altitude to the essential oils (EOs), fatty acid methyl esters (FAMEs), and antimicrobial activities of Primula vulgaris Huds. subsp. vulgaris (Pvv) and P. vulgaris Huds. subsp. sibthorpii (Hoffmanns) W.W.Sm. and Forrest (Pvs)) grown in Turkey were investigated. Major fluctuations in the composition of Pvv and Pvs oils included methyl-4-methoxy salicylate (4.5-35.3%; Pvv and 3.2-37.2%; Pvs), (Z,Z,Z)-7,10,13- hexadecatrienal (5.1-21.8%; Pvv and 4.4-15.2%; Pvs ) and flavone (5.5-14.9%; Pvv and 1.6-18.0%; Pvs). Fatty acid profile (C6:0-C26:0) changes were noted in Pvv and Pvs. Methyl hexadecanoate (2.4-9.3%) and methyl octadecanoate (1.0-4.7%) were present in all the FAME samples of the plants. The antimicrobial activity of the EOs of Pvv and Pvs were tested against nine bacterial species, which showed activity against Mycobacterium smegmatis with minimum inhibitory concentrations (MIC) varying from 8.5 to 59.2 ?g/mL in all samples, respectively, depending on the altitude at which the oils were obtained