QuCoLiMa Talk – Andreas Nunnenkamp – Directional amplification and non-Hermitian topology

Datum: 21. November 2023Zeit: 12:00 – 13:00Ort: On-site in Erlangen and livestream via Zoom


Andreas Nunnenkamp - Universität Wien


Directional amplification and non-Hermitian topology


Directional amplification, in which signals are selectively amplified depending on their propagation direction, has attracted much attention as a key resource for applications, including quantum information processing. I will present a unifying framework based on non-Hermitian topology to understand non-reciprocity and directional amplification in driven-dissipative cavity arrays. Specifically, I will unveil a one-to-one correspondence between a non-zero topological invariant defined on the spectrum of the dynamic matrix and regimes of directional amplification, in which the end-to-end gain grows exponentially with the number of cavities. I will then show that this correspondence also holds in the presence of disorder as long as the size of the point gap is larger than the disorder. Finally, I will show how to restore the bulk-boundary correspondence for one paradigmatic class of non-Hermitian Hamiltonians. Our work opens up new avenues in topological photonics and non-Hermitian phases of matter.



All talks hybrid:

Mixture of on-site talks at the main sites of QuCoLiMa (Erlangen, Mainz, Saarbrücken) as well as online talks. Regardless of where the talks are given, they are livestreamed via Zoom and can be watched from home/office or cooperatively in the following meeting rooms:

- Erlangen: Livestream/Presentation in Lecture hall HF + open sandwiches in the foyer afterwards

- Saarbrücken: Livestream/Presentation in tba

- Mainz: Livestream/Presentation in tba



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QuCoLiMa Talks are regular seminars of the collaborative research center TRR 306 QuCoLiMa (Quantum Cooperativity of Light and Matter), where (external) experts are invited to present their work.

More information at http://www.qucolima.de/talks

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21. November 2023
12:00 – 13:00

On-site in Erlangen and livestream via Zoom