Mesoscopic Rydberg Gate based on Electromagnetically Induced Transparency

We demonstrate theoretically a parallelized C-NOT gate which allows to entangle a mesoscopic ensemble of atoms with a single control atom in a single step, with high fidelity and on a microsecond timescale. Our scheme relies on the strong and long-ranged interaction between Rydberg atoms triggering Electromagnetically Induced Transparency (EIT). By this we can robustly implement a conditional transfer of all ensemble atoms among two logical states, depending on the state of the control atom. We outline a many body interferometer which allows a comparison of two many-body quantum states by performing a measurement of the control atom.Comment: published versio

Radikale onkologische Chirurgie als Therapieprinzip beim Pankreaskarzinom

Zusammenfassung: Grundlagen: Mit den heutigen tiefen Morbiditäts-und Mortalitätsraten für Pankreasresektionen ist die Indikationsstellung für eine Standard- oder pyloruserhaltende Whipple-Operation weniger restriktiv zu stellen. Methodik: Pankreasresektionen für Karzinome sollten deshalb in kurativer oder palliativer Absicht, wenn immer möglich, durchgeführt werden. Verlangt werden dafür erfahrene Chirurgen mit über 10 Pankreaseingriffen pro Jahr und einer Mortalität von unter 10%. Als Standard gilt eine 2reihige Pankreatikojejunostomie mit Y-Roux-Rekonstruktion sowie die peri- und postoperative Therapie mit Octreotid während 7 Tagen. Ergebnisse: Innerhalb von 32 Monaten wurden 113 Patienten mit Pankreaskarzinom behandelt. Die Resektionsrate lag bei 50%, bei der Mehrzahl der Fälle wurde eine pyloruserhaltende Whipple-Operation durchgeführt (30/57). Die postoperative Morbidität lag bei 22,3%, kein Patient verstarb. Schlußfolgerungen: Die erweiterte (radikale) Duodenopankreatektomie wird ihren Wert im Vergleich zur Standard- oder pyloruserhaltenden Duodenopankreatektomie in prospektivrandomisierten Studien erst noch belegen müssen. Die Wirksamkeit einer adjuvanten Chemo- und/oder Radiotherapie bedarf weiterer Überprüfung mittels prospektiver Studie

Supersolid phase with cold polar molecules on a triangular lattice

We study a system of heteronuclear molecules on a triangular lattice and analyze the potential of this system for the experimental realization of a supersolid phase. The ground state phase diagram contains superfluid, solid and supersolid phases. At finite temperatures and strong interactions there is an additional emulsion region, in contrast to similar models with short-range interactions. We derive the maximal critical temperature $T_c$ and the corresponding entropy $S/N = 0.04(1)$ for supersolidity and find feasible experimental conditions for its realization.Comment: 4 pages, 4 figure

Leading infrared logarithms for sigma-model with fields on arbitrary Riemann manifold

We derive non-linear recursion equation for the leading infrared logarithms (LL) in four dimensional sigma-model with fields on an arbitrary Riemann manifold. The derived equation allows one to compute leading infrared logarithms to essentially unlimited loop order in terms of geometric characteristics of the Riemann manifold. We reduce the solution of the SU(oo) principal chiral field in arbitrary number of dimensions in the LL approximation to the solution of very simple recursive equation. This result paves a way to the solution of the model in arbitrary number of dimensions at N-->ooComment: Talk given by MVP at the conference devoted to memory of A.N. Vasilie

Physical replicas and the Bose-glass in cold atomic gases

We study cold atomic gases in a disorder potential and analyze the correlations between different systems subjected to the same disorder landscape. Such independent copies with the same disorder landscape are known as replicas. While in general these are not accessible experimentally in condensed matter systems, they can be realized using standard tools for controlling cold atomic gases in an optical lattice. Of special interest is the overlap function which represents a natural order parameter for disordered systems and is a correlation function between the atoms of two independent replicas with the same disorder. We demonstrate an efficient measurement scheme for the determination of this disorder-induced correlation function. As an application, we focus on the disordered Bose-Hubbard model and determine the overlap function within perturbation theory and a numerical analysis. We find that the measurement of the overlap function allows for the identification of the Bose-glass phase in certain parameter regimes.Comment: 17 pages, 6 figures, updated and added several references, other minor changes and correction

Dressing of Ultracold Atoms by their Rydberg States in a Ioffe-Pritchard Trap

We explore how the extraordinary properties of Rydberg atoms can be employed to impact the motion of ultracold ground state atoms. Specifically, we use an off-resonant two-photon laser dressing to map features of the Rydberg states on ground state atoms. It is demonstrated that the interplay between the spatially varying quantization axis of the considered Ioffe-Pritchard field and the fixed polarizations of the laser transitions provides the possibility of substantially manipulating the ground state trapping potential.Comment: 11 pages, 4 figure