Junior Quantum Seminar - Marco Scigliuzzo & Aleksei Gaier

Please join us for the Junior Quantum Seminar with Marco Scigliuzzo from the Laboratory of Photonics and Quantum Measurements (LPQM), Institute of Physics, EPFL who will give the talk "Quantum acoustics with superconducting circuits" and Aleksei Gaier from the Laboratory of Hybrid Photonics, EPFL who will give the talk "Bridging electronics and photonics with thin-film lithium niobate: electro-optic transduction from microwaves to terahertz" on Tuesday November 28th from 9h30-11h.

PLEASE NOTE: The Junior Quantum Series are for gathering  the junior quantum community of master's students, PhDs and post-docs at EPFL, to create a non-judgmental space were scientific ideas can be shared between peers. This event is not for Professors or senior researchers. 

ABTRACT:
1. Quantum acoustics with superconducting circuits
    What does it take to push a massive object into a genuinely quantum state and then control many such objects at once? Mechanical oscillators offer a unique opportunity: their mass makes their quantum states sensitive to forces, fields, and even gravity, but that same mass also makes them extremely hard to manipulate and scale. Quantum acoustics tries to bridge this gap by using superconducting circuits to prepare, control, and measure individual phonons in engineered mechanical devices.
In this talk, I’ll discuss one of the central questions driving the field: how do we scale up mechanical quantum systems without losing quantum coherence or control? I will present our progress toward building a platform with multiple independently addressable mechanical modes whose motion can be measured with quantum-limited sensitivity, giving access to correlations and collective dynamics across distinct resonators. Collective effects, such as collective sideband cooling and collective dissipative squeezing, open the door to preparing and manipulating multiple mechanical modes in quantum states.
I will also show our efforts to create delocalized phonon-photon hybrid excitations by coupling chains of high overtone bulk acoustic resonators to superconducting circuits, an acoustic analogue of defects in a crystal band structure. Such excitations offer a promising route toward distributed quantum sensing and mechanically mediated quantum networks.
These developments outline a concrete path toward scalable quantum acoustics and toward using mechanical degrees of freedom as a resource in larger quantum technologies.

2. Bridging electronics and photonics with thin-film lithium niobate: electro-optic transduction from microwaves to terahertz
    Advances in thin-film lithium niobate (TFLN) technology are redefining the interface between high-frequency electronics and integrated photonics. In this talk, I will present our recent progress on electro-optic transduction in TFLN devices operating beyond 100 GHz, highlighting how photonic circuits can efficiently detect and manipulate electromagnetic signals well into the terahertz regime. By leveraging low-loss optical resonators with terahertz cavities formed by metallic electrodes and on-chip antennas, we demonstrate high-efficiency conversion of terahertz fields into the optical domain.
Beyond transduction, I will discuss our approach to characterizing incoherent terahertz radiation through optical correlation measurements, enabling new insight into the temporal and spectral statistics of broadband terahertz sources. I will present our initial results on this technique, demonstrating its ability to characterize continuous-wave terahertz sources.

BIO:
Marco Scigliuzzo is a postdoctoral researcher and QSE Fellow at the Laboratory of Photonics and Quantum Measurements (LPQM) at EPFL. His research focuses on hybrid quantum systems based on superconducting circuits and mechanical resonators, with an emphasis on microwave-phonon interactions and engineered circuit and waveguide QED, including qubits coherence and traveling-wave parametric amplification. He obtained his Master’s degree in Physics from the University of Salento and his PhD from Chalmers University of Technology, where he worked on superconducting qubits and quantum electromechanical systems.

Aleksei Gaier has completed his bachelor's and master's degrees at Lomonosov Moscow State University, where he worked in biophotonics, developing optical methods based on time-resolved fluorescence measurements to study the properties of blood serum. He started his PhD in November 2022, working on the thin-film lithium niobate integrated devices for applications in terahertz science.