Levitated quantum systems, ranging from trapped atoms and ions to mesoscopic particles, provide exceptional isolation from the environment and access to controllable motional degrees of freedom. Their full potential emerges from the interplay between motional, internal, and photonic degrees of freedom. Such hybrid architectures combine the high information capacity of continuous variables with the addressability and readout capabilities of discrete degrees of freedom, opening new possibilities for quantum sensing, information processing, and tests of fundamental physics. Recent advances in coherent control of motional quantum systems raise the question of how far these resources can be pushed beyond the Gaussian regime and utilized under realistic experimental conditions.

In the talk, I will present the following approaches to quantum state engineering and sensing with levitated systems.

(i) Universal control of motion via nonharmonic potentials: Optimal modulation of weakly nonharmonic trapping potentials enables deterministic preparation of quantum non-Gaussian states, including Fock, Schrödinger-cat, and Gottesman–Kitaev–Preskill states, as well as implementation of arbitrary unitaries within selected subspaces [1,3].

(ii) Large-scale motional quantum resources: Dynamical evolution in engineered nonlinear potentials enables rapid generation of large-scale non-Gaussian states and entangled motional resources, including macroscopic superpositions and mechanical Bell states [2,3].

(iii) Quantum-enhanced sensing with motional states: Quantum optimal control identifies families of non-Gaussian states that maximize sensitivity to weak forces under realistic decoherence. I will discuss phase-insensitive displacement sensing, distributed sensing protocols, and recent results demonstrating that quantum advantage can persist even without complete ground-state cooling [4–6].

These approaches provide a unified framework for engineering and exploiting nonclassical motional states across a wide range of platforms. Finally, I will outline ongoing directions involving neutral atoms, spin–photon–phonon quantum nodes, superradiance-enhanced tabletop sensing, cavity-QED-enhanced gravitational interferometry, and quantum sensing with atoms in optical tweezers.

[1] PTG, H. Pichler, C. A. Regal, O. Romero-Isart, Quantum control of continuous systems via nonharmonic potential modulation, Quantum 9, 1824 (2025)
[2] M. Roda-Llordes, A. Riera-Campeny, D. Candoli, PTG, O. Romero-Isart, Macroscopic quantum superpositions via dynamics in a wide double-well potential, Phys. Rev. Lett. 132, 023601 (2024)
[3] PTG, O. Romero-Isart, Quantum Non-Gaussian State Preparation of Levitated Particles via Time-Dependent Control of Weakly Nonharmonic Hybrid Potentials, arXiv:2606.10042 (2026)
[4] PTG, R. Filip, Optimal Phase-Insensitive Force Sensing with Non-Gaussian States, Phys. Rev. Lett. 135, 230802 (2025)
[5] PTG, M. Fadel, R. Filip, Distributed Phase-Insensitive Displacement Sensing, arXiv:2602.03727 (2026)
[6] PTG, To Cool, or Not to Cool? Displacement Sensing with Hot Quantum States, arXiv:2606.13650 (2026)

To operate quantum sensors at their quantum limit in real time, it is crucial to identify efficient data inference tools for rapid parameter estimation. In photodetection, the key challenge is the fast interpretation of click-patterns that exhibit non-classical statistics — the very features responsible for the quantum enhancement of precision. We achieve this goal by comparing Bayesian likelihood-free methods with approaches based on deep learning (DL). While the former are more conceptually intuitive, the latter, once trained, provide significantly faster estimates with comparable precision and yield similar predictions of the associated errors, challenging a common misconception that DL lacks such capabilities.<br><br>

We first verify both approaches for an analytically tractable, yet multiparameter, scenario of a two-level system emitting uncorrelated photons. Our main result, however, is the application to a driven nonlinear optomechanical device emitting non-classical light with complex multiclick correlations; in this case, our methods are essential for fast inference and thus unlock the possibility of distinguishing different photon statistics in real time.

[1] M. Teske, T. Sowiński, Phys. Rev. A 113, 013301 (2026)
[2] T. Sowiński, EPL 134, 33001 (2021)
[3] D. Pęcak, T. Sowiński, Phys. Rev. Res. 2, 012077(R) (2020)

Date: 22 May, 12:15 PM CET
Location: room D at Al. Lotników, also available on Zoom

Zoom link:
https://us06web.zoom.us/j/87057373249?pwd=MNnyk4rUf9cOVZoxeqIaKkhwYk5STm.1

The Kelvin–Helmholtz instability (KHI) in superfluid systems with annular geometry has recently attracted significant attention. While numerical studies based on Gross–Pitaevskii and Zaremba–Nikuni–Griffin models have explained some of its dynamics, they still predict the instability’s growth rates incorrectly. We employ the SLDA framework to simulate KHI in annular superfluid systems across interaction regimes for temperatures T/Tc ≈ 0.0 and 0.33, and compare the resulting dynamics and KHI growth rates with existing theoretical models and experimental observations. We do not observe sensitivity of the instability growth rate to the interaction regime (BCS vs UFG), in contrast to experimental findings. This discrepancy persists even when finite-temperature effects are included. Additionally, systematic deviations from the Point-Vortex Model are identified for modes with m/Δw ∈ (0.6, 0.8), for which no clear mechanism has been established. In the deep BCS regime, the dynamics change qualitatively: vortex proliferation at the inner edge of the ring dominates, operating on shorter timescales than KHI and suppressing its development. Our results indicate limitations of the SLDA in capturing experimentally observed interaction-dependent growth rates and reveal a competing instability mechanism in the BCS regime. These findings highlight unresolved aspects of vortex dynamics in annular superfluids and motivate further theoretical investigation.

Location: seminar room D, Al. Lotników 32/46, also available via Zoom under

https://us06web.zoom.us/j/87057373249?pwd=MNnyk4rUf9cOVZoxeqIaKkhwYk5STm.1

Over the past years there has been rapid development in hardware for quantum computing across a range of platforms. In parallel to these developments, highly controlled quantum systems ranging from ultra-cold atoms to superconducting qubits are being applied as “analogue quantum simulators” to study problems of interest in many-body physics. However, the big question is when and how they might answers to questions that we cannot address with simulation on classical computers.

I will give an introduction to the overarching question of what is difficult to compute regarding many-body systems, and how we might approach these questions using digital quantum computers, or analogue quantum simulators. I will discuss under which conditions the answers we get out of each platform are quantitatively reliable, and where we might expect to obtain a practical quantum advantage for simulation of quantum systems in the early fault-tolerant era of quantum computing.

The seminar will take place on Friday 2026-03-27 at 12:15 CET

in the Leonard Sosnowski Auditorium, Al. Lotników 32/46, 02-668 Warszawa
and
under the following link:
https://us06web.zoom.us/j/87057373249?pwd=MNnyk4rUf9cOVZoxeqIaKkhwYk5STm.1