Recoil-free spectroscopy of neutral Sr atoms in the Lamb-Dicke regime

We have demonstrated a recoil-free spectroscopy on the ${}^1S_0-{}^3P_1$ transition of strontium atoms confined in a one-dimensional optical lattice. By investigating the wavelength and polarization dependence of the ac Stark shift acting on the ${}^1S_0$ and ${}^3P_1(m_J=0)$ states, we determined the {\it magic wavelength} where the Stark shifts for both states coincide. The Lamb-Dicke confinement provided by this Stark-free optical lattice enabled the measurement of the atomic spectrum free from Doppler as well as recoil shifts.Comment: 5pages, 4figure

Experimental study of optimal measurements for quantum state tomography

Quantum tomography is a critically important tool to evaluate quantum hardware, making it essential to develop optimized measurement strategies that are both accurate and efficient. We compare a variety of strategies using nearly pure test states. Those that are informationally complete for all states are found to be accurate and reliable even in the presence of errors in the measurements themselves, while those designed to be complete only for pure states are far more efficient but highly sensitive to such errors. Our results highlight the unavoidable tradeoffs inherent to quantum tomography.Comment: 5 pages, 3 figure

Ad- and desorption of Rb atoms on a gold nanofilm measured by surface plasmon polaritons

Hybrid quantum systems made of cold atoms near nanostructured surfaces are expected to open up new opportunities for the construction of quantum sensors and for quantum information. For the design of such tailored quantum systems the interaction of alkali atoms with dielectric and metallic surfaces is crucial and required to be understood in detail. Here, we present real-time measurements of the adsorption and desorption of Rubidium atoms on gold nanofilms. Surface plasmon polaritons (SPP) are excited at the gold surface and detected in a phase sensitive way. From the temporal change of the SPP phase the Rubidium coverage of the gold film is deduced with a sensitivity of better than 0.3 % of a monolayer. By comparing the experimental data with a Langmuir type adsorption model we obtain the thermal desorption rate and the sticking probability. In addition, also laser-induced desorption is observed and quantified.Comment: 9 pages, 6 figure

Quantum state tomography by continuous measurement and compressed sensing

The need to perform quantum state tomography on ever larger systems has spurred a search for methods that yield good estimates from incomplete data. We study the performance of compressed sensing (CS) and least squares (LS) estimators in a fast protocol based on continuous measurement on an ensemble of cesium atomic spins. Both efficiently reconstruct nearly pure states in the 16-dimensional ground manifold, reaching average fidelities FCS = 0.92 and FLS = 0.88 using similar amounts of incomplete data. Surprisingly, the main advantage of CS in our protocol is an increased robustness to experimental imperfections

Лингвистические и культурологические традиции и инновации: сборник материалов Всероссийской научно-практической конференции "Актуальные проблемы управления и экономики", Томск, 12 декабря 2018 г.

В сборнике представлены материалы выступлений участников Всероссийской научно-практической конференции «Актуальные проблемы управления и экономики», проведённой 12 декабря 2018 года отделением иностранных языков ШБИП Национального исследовательского Томского политехнического университета. Настоящий сборник объединяет исследовательские проекты аспирантов и преподавателей, посвященные актуальным проблемам современной теории и методики преподавания иностранных языков и культур, теории и практики межкультурной коммуникации, исторического, сравнительного и сопоставительного языкознания. Сборник адресован аспирантам и преподавателям, а также всем, кого интересует теория и методика обучения иностранным языкам, изучение языков в их взаимосвязи с философией, литературой, историей и культурой

Four Phosphates at One Blow: Access to Pentaphosphorylated Magic Spot Nucleotides and Their Analysis by Capillary Electrophoresis

The complex phosphorylation pattern of natural and modified pentaphosphorylated magic spot nucleotides is generated in a highly efficient way. A cyclic pyrophosphoryl phosphoramidite (cPyPA) reagent is used to introduce four phosphates on nucleosides regioselectively in a one-flask key transformation. The obtained magic spot nucleotides are used to develop a capillary electrophoresis UV detection method, enabling nucleotide assignment in complex bacterial extracts

Quantum computations with atoms in optical lattices: marker qubits and molecular interactions

We develop a scheme for quantum computation with neutral atoms, based on the concept of "marker" atoms, i.e., auxiliary atoms that can be efficiently transported in state-independent periodic external traps to operate quantum gates between physically distant qubits. This allows for relaxing a number of experimental constraints for quantum computation with neutral atoms in microscopic potential, including single-atom laser addressability. We discuss the advantages of this approach in a concrete physical scenario involving molecular interactions.Comment: 15 pages, 14 figure