Quantum engineering of atomic phase-shifts in optical clocks

Quantum engineering of time-separated Raman laser pulses in three-level systems is presented to produce an ultra-narrow optical transition in bosonic alkali-earth clocks free from light shifts and with a significantly reduced sensitivity to laser parameter fluctuations. Based on a quantum artificial complex-wave-function analytical model, and supported by a full density matrix simulation including a possible residual effect of spontaneous emission from the intermediate state, atomic phase-shifts associated to Ramsey and Hyper-Ramsey two-photon spectroscopy in optical clocks are derived. Various common-mode Raman frequency detunings are found where the frequency shifts from off-resonant states are canceled, while strongly reducing their uncertainties at the 10$^{-18}$ level of accuracy.Comment: accepted for publication in PR

The Synthesis and Antiviral Properties of 8- Amino-3- [(2 hydroxyethoxy)methyl]-1,2,4-triazolo- [4,3-a ]pyrazine

The preparation of 8-amino-3-[(2-hydroxyethoxy)methyl]-1,2,4- triazolo[4,3-a]pyrazine (IV) as an analogue of 9-[(2-hydroxyethoxy) methyl]guanine and 9-(S)-(2,3-dihydroxypropyl)adenine is described from the reaction of 3-chloro-2-hydrazinopyrazine (V) and ethyl 2-(2-acetoxyethoxy)thioacetimidate (IXg) followed by treatment with ammonia. Compound IV was found to lack antiviral properties towards herpes simplex I and II, vaccinia virus, vesicular stomatitis virus, measles, reovirus type 1, parainfluenza virus type 3, Sindbis virus, Coxsackie type B4 virus, and poliovirus type

TEOS AND TIME: THE INLFUENCE OF APPLICATION SCHEDULES ON THE EFFECTIVENESS OF ETHYL SILICATE BASED CONSOLIDANTS

An investigation was carried out at KIK-IRPA on the application modalities of ethyl silicate based products aiming at understanding the influence of time between successive applications on the pore structure and on the final strengthening effect of stones. Samples of Maastrichter lime stone were treated with different formulations and dilutions. The number of treatments varied from one to three with an interval between successive treatments ranging from one day to three weeks. Mercury porosity measurements, polymerized product content and hardness profiles obtained by a drilling resistance measurement system (DRMS) were used to evaluate the consolidating properties. Noticeable differences in pore blocking and in overall hardness were observed in samples that were treated at one day intervals and those treated at three week intervals. The strengthening effect alsoseems to vary with the type of formulation