Nano & Quantum Sensors

Technical University of Munich

Depart. of Electrical and Computer Engineering

Theresienstr. 90/I

80333 Munich

+49 89 289 25332


Group website


Research focus: nanomechanical systems, cavity optomechanics and circuit electromechanics

Our research is centered around the experimental investigation of nanomechanical and cavity optomechanical systems. Within MQC / MCQST we are particularly interested in their exploitation for for hybrid quantum technologies.


High Q nanoresonators

Reaching ultimate mechanical quality factors is instrumental for the application of nanomechanical systems in quantum technologies. To this end, we are focussing on combing two approaches: Material engineering in order to identify material platforms providing minimum dissipation, and stress engineering in order to boost the mechanical quality factor via dissipation dilution.


Coherent control and state preparation

The nanomechanical two-mode system realized in the avoided crossing of two strongly coupled nanomechanical modes is a remarkable testbed to study Landau-Zener dynamics, Stückelberg interference, and Bloch sphere dynamics. At present, our research is focussing on the implementation of shortcuts to adiabaticity, coherent state preparation protocols allowing for a fast and high-fidelity state initialization.

Spectral evidence of squeezing

The generation of squeezed states can enable quantum sensing applications with higher sensitivity. While squeezed states are conveniently characterized by resolving the full phase space distribution of the underlying fluctuations, this method is not applicable to very high Q resonators. We are exploring spectral methods to characterize squeezed states using driven nonlinear nanomechanical resonators. In particular, two-tone measurements allow to map out not only the thermomechanical squeezing, but also a squeezed vacuum state directly from the response spectrum.

Selected Publications

  • Amplification and spectral evidence of squeezing in the response of a strongly driven nanoresonator to a probe field
    J. S. Ochs (née Huber), M. Seitner, M. I. Dykman, and E. M. Weig
    Phys. Rev. A 103, 013506 (2021)
  • Spectral Evidence of Squeezing of a Weakly Damped Driven Nanomechanical Mode
    J. S. Huber, G. Rastelli, M. J. Seitner, J. Kölbl, W. Belzig, M. I. Dykman, and E. M. Weig
    Phys. Rev. X 10, 021066 (2020)


Optomechanics for quantum technologies

S. Barzanjeh, A. Xuereb, S. Gröblacher, M. Paternostro, C.A. Regal, E.M. Weig

Nature Physics 18, 15-24 (2022).

Show Abstract

Interaction with light can be used to precisely control motional states. This Review surveys recent progress in the preparation of non-classical mechanical states and in the application of optomechanical platforms to specific tasks in quantum technology. The ability to control the motion of mechanical systems through interaction with light has opened the door to a plethora of applications in fundamental and applied physics. With experiments routinely reaching the quantum regime, the focus has now turned towards creating and exploiting interesting non-classical states of motion and entanglement in optomechanical systems. Quantumness has also shifted from being the very reason why experiments are constructed to becoming a resource for the investigation of fundamental physics and the creation of quantum technologies. Here, by focusing on opto- and electromechanical platforms we review recent progress in quantum state preparation and entanglement of mechanical systems, together with applications to signal processing and transduction, quantum sensing and topological physics, as well as small-scale thermodynamics.

DOI: 10.1038/s41567-021-01402-0

Room temperature cavity electromechanics in the sideband-resolved regime

A.T. Le, A. Brieussel, E.M. Weig

Journal of Applied Physics 130, 014301 (2021).

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We demonstrate a sideband-resolved cavity electromechanical system operating at room temperature. It consists of a nanomechanical resonator, a strongly pre-stressed silicon nitride string, dielectrically coupled to a three-dimensional microwave cavity made of copper. The electromechanical coupling is characterized by two measurements, the cavity-induced eigenfrequency shift of the mechanical resonator and the optomechanically induced transparency. While the former is dominated by dielectric effects, the latter reveals a clear signature of the dynamical backaction of the cavity field on the resonator. This unlocks the field of cavity electromechanics for room temperature applications.

DOI: 10.1063/5.0054965

Universal Length Dependence of Tensile Stress in Nanomechanical String Resonators

M. Bückle, Y.S. Klaß, F.B. Nägele, R. Braive, E.M. Weig

Physical Review Applied 15, 034063 (2021).

Show Abstract

We investigate the tensile stress in freely suspended nanomechanical string resonators, and observe a material-independent dependence on the resonator length. We compare strongly stressed string resonators fabricated from four different material systems based on amorphous silicon nitride, crystalline silicon carbide as well as crystalline indium gallium phosphide. The tensile stress is found to increase by approximately 50% for shorter resonators. We establish a simple elastic model to describe the observed length dependence of the tensile stress. The model accurately describes our experimental data. This opens a perspective for stress engineering the mechanical quality factor of nanomechanical string resonators.

DOI: 10.1103/PhysRevApplied.15.034063

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