4 research outputs found

    Rydberg crystallization detection by statistical means

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    We investigate an ensemble of atoms which can be excited into a Rydberg state. Using a disordered quantum Ising model, we perform a numerical simulation of the experimental procedure and calculate the probability distribution function P(M)P(M) to create a certain number of Rydberg atoms MM, as well as their pair correlation function. Using the latter, we identify the critical interaction strength above which the system undergoes a phase transition to a Rydberg crystal. We then show that this phase transition can be detected using P(M)P(M) alone.Comment: 7 pages, 9 figure

    Detecting an exciton crystal by statistical means

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    We investigate an ensemble of excitons in a coupled quantum well excited via an applied laser field. Using an effective disordered quantum Ising model, we perform a numerical simulation of the experimental procedure and calculate the probability distribution function P(M)P(M) to create MM excitons as well as their correlation function. It shows clear evidence of the existence of two phases corresponding to a liquid and a crystal phase. We demonstrate that not only the correlation function but also the distribution P(M)P(M) is very well suited to monitor this transition.Comment: 5 pages, 5 figure

    Statistical properties of interacting Rydberg gases

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    The present thesis treats the interacting ultracold Rydberg gas with special emphasison the statistical footprint of the phase transition between unordered and crystalline phase, which can be understood as a consequence of the dipole blockade effect. After mapping the system onto an effective spin-1/2-model, exact diagonalization of the effective Hamiltonian is used to obtain the many-body ground state. Repeated application of this procedure on random realizations reveals the underlying probability distribution of the number of Rydberg atoms, allowing to calculate its statistical moments. In the regimes of weak and strong interaction these observables have power law character. The critical interaction strength is estimated by extrapolating these power laws up to their intersection point. The same procedure is applied to interacting excitons in bilayer heterostructures uncovering a phase transition here as well. Furthermore, new methods are introduced to handle the effects of finite detection efficiency and parameter fluctuations to establish a better connection between experimental and theoretical results. Finally, new models are introduced to include dynamics or additional Rydberg states. The last model is of purely statistical nature and its results may be used as a tool for detecting a potential clustering of Rydberg atoms

    Restriction fragment length polymorphisms at the human parathyroid hormone gene locus

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    Two common Pst I and Taq I restriction enzyme fragment length polymorphisms (RFLPs) were detected at the human parathyroid hormone (PTH) gene locus. The allele frequencies in a Northern German population were 0.578/0.422 (Pst I) and 0.628/0.372 (Taq I). The allele distributions follow Hardy-Weinberg expectations of equilibrium in the population. The Mendelian nature of the polymorphisms were confirmed in family studies
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