Quantum limits to estimation of photon deformation

We address potential deviations of radiation field from the bosonic behaviour and employ local quantum estimation theory to evaluate the ultimate bounds to precision in the estimation of these deviations using quantum-limited measurements on optical signals. We consider different classes of boson deformation and found that intensity measurement on coherent or thermal states would be suitable for their detection making, at least in principle, tests of boson deformation feasible with current quantum optical technology. On the other hand, we found that the quantum signal-to-noise ratio (QSNR) is vanishing with the deformation itself for all the considered classes of deformations and probe signals, thus making any estimation procedure of photon deformation inherently inefficient. A partial way out is provided by the polynomial dependence of the QSNR on the average number of photon, which suggests that, in principle, it would be possible to detect deformation by intensity measurements on high-energy thermal states.Comment: 9 page

Squeezing-enhanced phase-shift-keyed binary communication in noisy channels

We address binary phase-shift-keyed communication channels based on Gaussian states and prove that squeezing improves state discrimination at fixed energy of the channel, also in the presence of phase diffusion. We then assess performances of homodyne detection against the ultimate quantum limits to discrimination, and show that homodyning achieves optimality in large noise regime. Finally, we consider noise in the preparation of the seed signal (before phase encoding) and show that also in this case squeezing may improve state discrimination in realistic conditions.Comment: 6 pages, 5 figure

Stein's method and exact Berry--Esseen asymptotics for functionals of Gaussian fields

We show how to detect optimal Berry--Esseen bounds in the normal approximation of functionals of Gaussian fields. Our techniques are based on a combination of Malliavin calculus, Stein's method and the method of moments and cumulants, and provide de facto local (one-term) Edgeworth expansions. The findings of the present paper represent a further refinement of the main results proven in Nourdin and Peccati [Probab. Theory Related Fields 145 (2009) 75--118]. Among several examples, we discuss three crucial applications: (i) to Toeplitz quadratic functionals of continuous-time stationary processes (extending results by Ginovyan [Probab. Theory Related Fields 100 (1994) 395--406] and Ginovyan and Sahakyan [Probab. Theory Related Fields 138 (2007) 551--579]); (ii) to ``exploding'' quadratic functionals of a Brownian sheet; and (iii) to a continuous-time version of the Breuer--Major CLT for functionals of a fractional Brownian motion.Comment: Published in at http://dx.doi.org/10.1214/09-AOP461 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

Highly scab-resistant transgenic apple lines achieved by introgression of HcrVf2 controlled by different native promoter lengths

Apple scab, caused by the ascomycete Venturia inaequalis, is the most damaging fungal disease of commercial apple orchards. Functional scab resistance genes are present in some wild Malus species. The HcrVf2 gene, derived from the Vf-region of the wild apple Malus floribunda 821 and encoding a receptor-like protein, has proved to confer scab resistance in a transgenic susceptible cultivar. In order to minimize nonplant DNA in genetically modified apple and to go a step toward the development of cisgenic apples, we have studied the capability of the HcrVf2 gene to confer apple scab resistance when it is controlled by its own promoter. Three promoter deletion constructs containing 115, 288, and 779bp of the 5′ untranslated region and the HcrVf2 gene were used to transform the scab susceptible apple cvs. ‘Gala' and ‘Elstar.' The influence of the promoter length on both the HcrVf2 expression level and the response to V. inaequalis was analyzed in different transgenic lines. Promoter length was found to influence both the constitutive transcription levels of HcrVf2 in transgenic lines and the resistance level. Highly scab resistant ‘Elstar' and ‘Gala' plants were obtained, proving that the HcrVf2 gene controlled by its native promoter is effective in conferring resistance to V. inaequalis similarly as Vf introgressed in apple cvs. through classical breedin

Identification of proteins associated with ligand-activated estrogen receptor alpha in human breast cancer cell nuclei by tandem affinity purification and nanoLC-MS/MS.

Estrogen receptor a (ER-a) is a key mediator of estrogen actions in breast cancer (BC) cells. Understanding the effects of ligand-activated ER-a in target cells requires identification of the molecular partners acting in concert with this nuclear receptor to transduce the hormonal signal. We applied tandem affinity purification (TAP), glycerol gradient centrifugation and MS analysis to isolate and identify proteins interacting with ligand-activated ER-a in MCF-7 cell nuclei. This led to the identification of 264 ER-associated proteins, whose functions highlight the hinge role of ER-a in the coordination of multiple hormone-regulated nuclear processes in BC cells