There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

Bose-Einstein condensation in a gas of sodium atoms

Feshbach resonances are the essential tool to control the interaction between atoms in ultracold quantum gases. They have found numerous experimental applications, opening up the way to important breakthroughs. This review broadly covers the phenomenon of Feshbach resonances in ultracold gases and their main applications. This includes the theoretical background and models for the description of Feshbach resonances, the experimental methods to find and characterize the resonances, a discussion of the main properties of resonances in various atomic species and mixed atomic species systems, and an overview of key experiments with atomic Bose-Einstein condensates, degenerate Fermi gases, and ultracold molecules.

Feshbach resonances in ultracold gases

日本物理学会誌及びJournal of the Physical Society of Japanの月刊について

We report all-optical Bose-Einstein-Condensation of sodium in a far-detuned crossed-dipole-trap. Sub-doppler-cooled sodium atoms are loaded into a crossed-dipole-trap and subsequently condensed by optical evaporation which yields condensates of 150000 atoms distributed over several spin-states.

All-Optical Bose-Einstein-Condensation of Sodium in a Crossed Dipole Trap

In this work, we measure the properties of ensembles of rubidium atoms trapped in solid neon that are relevant for use as quantum sensors of magnetic fields: the spin coherence of the trapped atoms and the ability to optically control and measure their spin state. We use the rubidium atoms as an AC magnetometer---by employing an appropriate dynamical decoupling sequence---and demonstrate NMR detection of $^{21}\mathrm{Ne}$ atoms co-trapped in the neon matrix.

Optical and spin-coherence properties of rubidium atoms trapped in solid neon

We propose a method of stimulated laser cooling of diatomic molecules by counter-propagating �-trains of ultrashort laser pulses. The cooling cycles occur on the rovibrational transitions inside the same ground electronic manifold, thus avoiding the common problem of radiative branching in Doppler cooling of molecules. By matching the frequency comb spectrum of the pulse trains to spectrum of the R-branch rovibrational transitions we show that stimulated cooling can be carried out on several rovibrational transitions simultaneously, thereby increasing number of cooled molecules. The exerted optical force does not rely on the decay rates in a system and can be orders of magnitude larger than the typical values of scattering force obtained in conventional Doppler laser cooling schemes.

/pdf/stimulated-cooling-of-molecules-on-multiple-rovibrational-3r5iryost0.pdf

Stimulated cooling of molecules on multiple rovibrational transitions with coherent pulse trains

By driving photoassociation transitions with continuous-wave lasers, we stateselectively form excited-state molecules from ultra cold atoms. Using a second laser to drive transitions from the excited molecular state to another long-lived molecular state, we are able to observe an interference dip narrower than the natural linewidth of the excited molecular state. The linewidth of the dip is strongly effected by the temperature of the atoms. To reach smaller linewidths we have set up an all optical BEC.

Quantum Interference in an Atom Molecule System

Autler-Townes spectroscopy is performed to investigate the coherence properties between ultra-cold atoms and sodium-dimers generated by photoassociation. Ultra-cold molecules have recently generated new interest due to the accomplishment of Bose-Einstein-condensation (BEC) of molecules and offer a variety of new approaches for a better understanding of atomic and molecular physics, precision measurements and fundamental research.

http://ieeexplore.ieee.org/iel5/10482/33238/01567388.pdf

Jonathan D. Weinstein

Papers

All-Optical Bose-Einstein-Condensation of Sodium in a Crossed Dipole Trap

Optical and spin-coherence properties of rubidium atoms trapped in solid neon

Stimulated cooling of molecules on multiple rovibrational transitions with coherent pulse trains

Quantum Interference in an Atom Molecule System

Dark superposition states between ultra-cold atoms and molecules generated by photoassociation