IQP Seminar: Isolating test masses for gravitational wave detection with modern control and machine learning; Interferometry of Efimov trimers based on modulated magnetic fields; Dynamics in an atom-cavity system: from non-equilibrium phases to technological applications

by Daniel Hartwig (IQP), George Bougas (IQP), Jim Skulte (IQP)

Wednesday 25 Oct 2023, 13:30 → 15:00 Europe/Berlin

ZOQ Center for Optical Quantum Technologies, Luruper Chaussee 149, bldg. 69

First Speaker: Daniel Hartwig, IQP

Title: Isolating test masses for gravitational wave detection with modern control and machine learning


Abstract: I will give an overview on one completed and multiple ongoing projects that strive for improving the sensitivity of current and future gravitational wave observatories by suppressing and cancelling noise sources around the suspensions of their test masses. The projects include multi-stage active seismic isolation platforms to reduce the need for active control closer to the test masses, reduction of sensor noise coupling to sensitive degrees of freedom using modern state-space control methods and machine learning for feedforward-cancellation of witnessed environmental noise. These methods are applied to the miniature gravitational wave detector prototype miniET to help in exploring optical design challenges of future gravitational wave detectors.


Second Speaker: George Bougas, IQP


Title: Interferometry of Efimov trimers based on modulated magnetic fields


Abstract: We demonstrate that an interferometer based on modulated magnetic field pulses enables precise characterization of the energies and lifetimes of Efimov trimers irrespective of the magnitude and sign of the interactions in 85Rb thermal gases. Despite thermal effects, interference fringes develop when the dark time between the pulses is varied. This enables the selective excitation of coherent superpositions of trimer, dimer and free atom states. The interference patterns possess two distinct damping timescales at short and long dark times that are either equal to or twice as long as the lifetime of Efimov trimers, respectively. Specifically, this behavior at long dark times provides an interpretation of the unusually large damping timescales reported in a recent experiment with 7Li thermal gases [Phys. Rev. Lett. 122, 200402 (2019)].


Third Speaker: Jim Skulte, IQP

Title: Dynamics in an atom-cavity system: from non-equilibrium phases to technological applications


Abstract: In this talk, I will briefly discuss the normal to superradiant phase transition of the Dicke model realized in a cavity-BEC setup. Afterwards, I will discuss our recent proposal to utilize cavity-BEC systems to create a rotational sensor. We propose to couple an array of Bose-Einstein condensates to a single quantized light mode of a high-finesse optical cavity. By measuring the photon emission in the superradiant phase, we can detect changes in the external rotations in real time, which is crucial for inertial navigation. We obtain an analytical expression for the phase boundaries and use a semi-classical phase-space method to map out the phase diagram numerically. We further suggest operating the sensor with a bias rotation, and to enlarge the enclosed area, to enhance the sensitivity of the sensor. With these ingredients, the dependence of the superradiant phase transition on the rotation frequency supports a highly sensitive and fast rotation sensor.


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Upcoming events:

Nov 15  Joyce Kwan (Harvard U)

Dec 14  Thu! Jean-Philippe Brantut (EPFL)

Jan 10  Christopher Foot (U Oxford)

Jan 31  Sebastian Will (Columbia U)

 

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Zoom data, for the entire semester:

https://uni-hamburg.zoom.us/j/63754275322?pwd=OVYzMXJSUzdyTE0zN0FOYitsSVA3QT09

Meeting-ID: 637 5427 5322
Kenncode: 58810268