Community Research and Development Information Service - CORDIS

Periodic Report Summary 1 - CAVITYMICROSCOPE (A Cavity-based Microscope for Quantum Gases)

Project context and objectives. Exploiting fascinating quantum properties for novel technical applications is appealing but still a dream. However, fundamental understanding of quantum systems and their behavior can be obtained by sensitive high-resolution detection of model systems, such as ultracold quantum gases. This is the concept behind the ’CavityMicroscope’ project: A novel microscope, based on sensitive detection of atoms evolving within a high-finesse optical cavity. Beyond that, the coupling to the cavity also allows to induce controlled, quantum limited interactions between distant atoms, facilitating the realization of a tailored interacting, many-body quantum system under measurement.

Work performed and main results so far. Cold atom experiments routinely deliver samples with excellent control over both external and internal degrees of freedom. In CavityMicroscope, we combine such quantum systems with quantum-limited sensing facilitated by a high-finesse optical cavity, opening the initially well isolated quantum system to the environment in a controlled manner.

Building on our demonstration of quantum limited force detection, we realize the quantum limited coupling of two mechanical oscillators. Here, we utilize core abilities of CavityMicroscope, such as single site addressing, quantum limited monitoring and sensitive, real-time position measurement to enter a novel physical regime.

In another line of research, we employ the coupling of the atomic spin to the cavity light, and create a spin-analog to a harmonic oscillator, allowing for dynamic sensing and control of the collective atomic spin. This gives us access to unique features of spin-optodynamics, such as a negative temperature, high-energy 'ground state'. We further demonstrate the coherent, autonomous feedback of cavity light to the spin dynamics.

Beyond that, we developed novel analysis tools, relevant for monitoring and state estimation in the time domain. Fostered by this development, in a collaboration with theory (Dr. Lukas Buchmann, Aarhus University), we propose a novel detection scheme capable of accounting for quantum backaction and to beat quantum limits in precision sensing, as for instance, in quantum limited force measurements.

Expected final results and their impact and use. Our demonstration of coupling of quantum objects by photons limited by measurement backaction has far reaching implications for the understanding of more complex quantum systems. Our results shed light onto the role of dissipation in more complex, interacting quantum systems under measurement. Further, we address more technological implications, as for instance the limitations of quantum networks created with the help of lossy photon channels, relevant for quantum technology. The novel detection schemes and analysis tools we developed pave the way to non-destructively study and steer the dynamics of quantum systems. Further, our experiments open the way for utilizing the spin degree of freedom in cold atoms for precision measurements and the design of quantum systems.

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Berthold Klein, (Deputy of Department Head)
Tel.: +49 631 205 3602
Fax: +49 631 205 4380


Life Sciences
Record Number: 187647 / Last updated on: 2016-08-22
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