We're moving to TU Wien!

1 February 2025

The group is starting afresh across town in the Atominstitut of TU Wien. Our brand new lab is entirely furbished and ready to see a build-up of new experiments! Stay tuned and reach out if you're interested in a visit.

START Award for Uroš Delić

20 June 2024

Uroš Delić received one of the prestigious START Awards from the Austrian Science Fund (FWF). This will allow the group to build experiments that explore nonreciprocal interactions between optically levitated nanoparticles in the quantum regime. Our research will be hosted by TU Wien. You can read more about the research questions which we will explore here (in German).

© Luiza Puiu

Dr. Murad Abuzarli receives MSCA postdoctoral fellowship

01 April 2023

Ultrastrong linear optomechanical interaction

Kahan Dare, Jannek J. Hansen, Iurie Coroli, Aisling Johnson, Markus Aspelmeyer, Uroš Delić

Phys. Rev. Research 6, L042025 (2024),  arXiv: 2305.16226 (2023)

Our study on the linear ultrastrong optomechanical coupling of an optically trapped nanoparticle to an optical cavity is now published in Phys. Rev. Research! In this work, we measure coupling rates of up to 55% of the bare mechanical frequency. Our system exploits the coherent coupling scheme by the transverse drive through the particle, which yields a genuinely linear interaction Hamiltonian. In such a system, as one of the eigenmodes experiences an inverted harmonic potential, the system can reach instability if the coupling rate exceeds 50% of the mechanical frequency. This effect could create squeezed states of mechanical motion (see this work for more details).

Non-Hermitian dynamics and non-reciprocity of optically coupled nanoparticles

Manuel Reisenbauer, Henning Rudolph, Livia Egyed, Klaus Hornberger, Anton V. Zasedatelev, Murad Abuzarli, Benjamin A. Stickler, Uroš Delić

Nature Physics 20, 1629 (2024), arXiv: 2310.02610

Our work on non-Hermitian dynamics of nonreciprocally and nonlinearly coupled optically levitated nanoparticles has just been published in Nature Physics. In this work, we observe PT symmetry breaking by reconstructing the eigenmodes with non-degenerate damping rates. For a larger coupling rate, the system exhibits a collective transition into a mechanical lasing state, where both particles become nonlinear oscillators. Larger arrays of particles will allow us to study nonreciprocal phase transitions or explore novel sensing strategies. Read more about it in our press release or the Nature News & Views article by our colleague Jayadev Vijayan.

Fluctuation-induced Forces on Nanospheres in External Fields

Clemens Jakubec, Pablo Solano, Uroš Delić, Kanu Sinha

Phys. Rev. A 109, 052807 (2024), arXiv: 2311.10496

In this work, we apply the tools of macroscopic quantum electrodynamics to calculate the interaction between two optically levitated nanoparticles. We recover the optical binding forces, as well as the Casimir-Polder interaction. Furthermore, we investigate how a squeezed vacuum state of light can also result in optical interactions between two nanoparticles.