Homodyne locking of a squeezer

We report on the successful implementation of a new approach to locking the frequencies of an OPO-based squeezed-vacuum source and its driving laser. The technique allows the simultaneous measurement of the phase-shifts induced by a cavity, which may be used for the purposes of frequency-locking, as well as the simultaneous measurement of the sub-quantum-noise-limited (sub-QNL) phase quadrature output of the OPO. The homodyne locking technique is cheap, easy to implement and has the distinct advantage that subsequent homodyne measurements are automatically phase-locked. The homodyne locking technique is also unique in that it is a sub-QNL frequency discriminator.Comment: Accepted to Optics Letter

Triazolinedione-'clicked' poly(phosphoester)s : systematic adjustment of thermal properties

The thermal properties of halogen-free flame retardant poly(phosphoester)s from acyclic diene metathesis polycondensation have been optimized by a systematic post-modification using 1,2,4-triazoline- 3,5-dione derivatives. The straightforward modification not only increased their glass transition temperatures significantly but also improved the thermal stability with respect to their char yields

Experimental test of strongly non-classical character of a noisy squeezed single-photon state

We experimentally verify the quantum non-Gaussian character of a conditionally generated noisy squeezed single-photon state with positive Wigner function. Employing an optimized witness based on probabilities of squeezed vacuum and squeezed single-photon states we prove that the state cannot be expressed as a mixture of Gaussian states. In our experiment, the non-Gaussian state is generated by conditional subtraction of a single photon from squeezed vacuum state. The state is probed with a homodyne detector and the witness is determined by averaging a suitable pattern function over the measured homodyne data. Our experimental results are in good agreement with a theoretical fit obtained from a simple yet realistic model of the experimental setup.Comment: 10 pages, 8 figures, REVTeX

Separating the classical and quantum information via quantum cloning

An application of quantum cloning to optimally interface a quantum system with a classical observer is presented, in particular we describe a procedure to perform a minimal disturbance measurement on a single qubit by adopting a 1->2 cloning machine followed by a generalized measurement on a single clone and the anti-clone or on the two clones. Such scheme has been applied to enhance the transmission fidelity over a lossy quantum channel.Comment: 4 pages, 2figure

Experimental Purification of Single Qubits

We report the experimental realization of the purification protocol for single qubits sent through a depolarization channel. The qubits are associated with polarization encoded photon particles and the protocol is achieved by means of passive linear optical elements. The present approach may represent a convenient alternative to the distillation and error correction protocols of quantum information.Comment: 10 pages, 2 figure

Effect of Strontium Ranelate on Femur Densitometry and Antioxidative/Oxidative Status in Castrated Male Rats

The studies were aimed at determinatning of the effect of strontium ranelate (SR) on the mineralization  processes and selected parameters of oxidative stress in orchidectomized rats during the development of  osteopenia. Male Wistar rats were sham-operated (SHO) and orchidectomized (ORX). ORX animals were  divided into control (ORX-C) and gavaged with SR (ORX-SR), at a dose of 900mg/kg/b.w. After 60 days  the animals were scanned for determination of bone mineral density (BMD) of the whole skeleton. Isolated  femora were examined by DEXA and pQCT. Tomographic measurements were performed for a total  slice and separately for the cortical and trabecular parts of the distal end of the femora. The intensity of  lipid peroxidation (ILP) and total antioxidant capacity (TAC) in blood serum were measured. SR treatment  increased vBMD and BMC of total, trabecular and cortical bone in ORX rats compared to ORX-C and  SHO rats. ORX significantly increased TAC in control animals, and SR limited this increase. ILP in SHO  and ORX-C rats which on a similar level. SR increased ILP by 21.3%, as compared to SHO. SR improved  densitometric and geometric parameters of femora by orchidectomized rats what prevented degradation of  bone tissue. Beneficial effects of SR were also demonstrated in stabilization of TAC in ORX rats at the level  noted in SHO rats.