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Quantum technologies

Dieter Meschede's research group
Home AMO physics colloquia
  • Iacopo Carusotto

  • Invited speaker: Dr. Iacopo Carusotto
    Affiliation: Università di Trento
    Title: Theory And Experiments With Quantum Fluids Of Light
    Time and room: 17:15 lecture hall IAP
    Abstract: A few years after the first observation of Bose-Einstein condensation, quantum gases of dressed photons in semiconductor microcavities (the so-called exciton-polaritons) are a powerful workbench for the study of phase transitions and many-body effects in a novel non-equilibrium context.
    In this talk, I will first briefly review remarkable experiments investigating superfluid hydrodynamics effects in photon fluids hitting localized defects: depending on the flow speed, a wide range of behaviors have been observed, from superfluid flow, to the super-sonic Mach cone, to the nucleation of topological excitations such as solitons and vortices. I will then illustrate recent theoretical studies in the direction of generating strongly correlated photon gases, from Tonks-Girardeau gases of impenetrable photons in one-dimension, to quantum Hall liquids in the presence of artificial magnetic fields.
    Advantages and disadvantages of the different material platforms in view of generating and detecting strongly correlated gases will be reviewed, in particular laterally patterned microcavity and micropillar devices in the optical range, and circuit-QED devices in the microwave domain.

  • Hendrik Ulbricht

  • Invited speaker: Dr. Hendrik Ulbricht
    Affiliation: University of Southampton
    Title: Centre of Mass Motion Interferometry of Molecules and Nanoparticles
    Time and room: 17:15 lecture hall IAP
    Abstract: The motivation for de Broglie interference of heavy particles is manifold, for example, to address the foundations of physics by invesitgating the quantum to classical transition, the use of interferometric techniques for applications such as: molecule metrology, molecule sorting, molecule quantum interference lithography and investigations of van der Walls/Casimir-Polder interactions, and to study the coherent manipulation of complex partciles for instance to reconstruct the Wigner function of the motional quantum state of the diffracted molecules. The centre of mass interferometry is not affected by internal excitation of the molecules as impressively demonstrated by our experiments. If however internal state dynamics is coupled to the centre of mass motion by electric or optical fields, the interference pattern is changed. I will explain our experiment on mapping the dynamics of the change of conformation of hot molecules onto its centre of mass motion while measuring the interference pattern. I will further emphasise the status of the develpoment of the Southampton molecule interferometer, where we recently achieved 27% of quantum contrast.

  • Clive Emary

  • Invited speaker: Dr. Clive Emary
    Affiliation: Institut für Theoretische Physik, TU Berlin
    Title: Distinguishing quantum from classical transport with the Leggett-Garg inequality
    Time and room: 17:15 lecture hall IAP
    Abstract: The Leggett-Garg inequality, often described as a temporal Bell's inequality, sets a bound on the nature of correlations of a single system at different times. Violation of this inequality implies the absence of a macroscopic real, i.e. classical probabilistic, description of the system.

    In this talk I shall introduce the Leggett-Garg inequality and discuss how it can be used to gain insight into whether a transport process operates under classical or quantum-mechanical laws. I will discuss realisations with quantum dots and electron interferometers, as well as make a connection with the theory of full counting statistics.

  • Master talks

  • 17:00  Martin Pofahl: "Construction of Neuronal Connectivity Maps Using Selective Plane Illumination Microscopy"
    17:40  Anna Hambitzer: "Direct Synthesis Of Light Polarization For State-Dependent Transport of Atoms"
    18:40  Natalie Thau: "Fiber Cavities"
    19:20  Sebastian Manz: "Heterodyne Spectroscopy With Single Atoms In A High-Finesse Optical Cavity"
    Room: lecture hall IAP

  • Tobias Salger

  • Invited speaker: Dr. Tobias Salger
    Affiliation: d-fine GmbH
    Title: Modern Risk Management
    Time and room: 10:15 lecture hall IAP