Juliette Monsel¶
I am a researcher in the group Dynamics and thermodynamics of nanoscale devices, in the Applied Quantum Physics Laboratory, in the Department of Microtechnology and Nanoscience at Chalmers University of Technology, in Gothenburg, Sweden.
I did my Ph.D. under the supervision of Alexia Auffèves at the Institut Néel (CNRS, Université Grenoble Alpes) in Grenoble, France. My thesis dissertation, entitled Quantum Thermodynamics and Optomechanics, was awarded a Springer Thesis Award and published in the Springer Theses series in 2020. Since 2020, I have been working with Janine Splettstoesser at Chalmers, first as a postdoctoral researcher and, since 2024, as a permanent researcher. I am also collaborating closely with Witlef Wieczorek’s experimental group at Chalmers on cavity optomechanics.
My research interests are:
quantum thermodynamics
open quantum systems
optomechanics
quantum optics
electronic transport
News¶
New preprint – July 24, 2026
Optomechanical systems with a Fano membrane in the middle
Lei Du, Aymeric Frerejean, Witlef Wieczorek, Janine Splettstoesser, Juliette Monsel
Conventional membrane-in-the-middle (MIM) optomechanical systems offer limited control over the optical linewidth, which can limit their performance when operating in the unresolved-sideband regime. We investigate cavity optomechanics with a photonic-crystal Fano membrane placed at the center of a Fabry-Pérot (FP) cavity. In contrast to a conventional dielectric membrane, the photonic-crystal membrane supports a localized optical resonance, which hybridizes with the cavity field and enables spectral engineering of the relevant optical modes. Besides the usual dispersive optomechanical coupling associated with cavity-length changes, the membrane motion also modifies the Fano-mode resonance and its hybridization with the cavity field. We consider two limits set by the membrane reflectivity: a transparent-membrane regime with a single FP-like mode, and a reflective-membrane regime with two coupled subcavity modes. In the latter case, only the symmetric cavity mode hybridizes with the Fano mode, while the antisymmetric mode remains decoupled. Using quantum Langevin equations together with a transfer-matrix description of the optical scattering problem, we show that the Fano-induced hybridization can generate narrow optical normal modes that remain efficiently accessible to the external drive for experimentally realistic parameters. These modes can provide effective sideband resolution and enable ground-state cooling of the membrane motion even when the bare cavity is in the unresolved-sideband regime. Our results establish Fano MIM systems as a promising platform for spectral and optomechanical engineering.
Accepted article – July 6, 2026
Sources of nonlinearity of a driven carbon nanotube electromechanical resonator
Sofia Sevitz, Kushagra Aggarwal, Jorge Tabanera-Bravo, Juliette Monsel, Florian Vigneau, Federico Fedele, Joe Dunlop, Juan M.R. Parrondo, Gerard J. Milburn, Janet Anders, Natalia Ares, Federico Cerisola
Nanoelectromechanical resonators provide an ideal platform for investigating the interplay between electron transport and nonlinear mechanical motion. Externally driven suspended carbon nanotubes, containing an electrostatically defined quantum dot are especially promising. These devices possess two main sources of nonlinearity: the electromechanical coupling and the intrinsic contributions of the resonator that induce a Duffing-like nonlinear behavior. In this work, we observe the interplay between the two sources across different driving regimes. The main nonlinear feature we observe is the emergence of arch-like resonances in the electronic transport when the resonator is strongly driven. We show that our model is in good agreement with our experimental electron transport measurements on a suspended carbon nanotube. This characterization paves the way for the exploration of nonlinear phenomena using mesoscopic electromechanical resonators.
New article – July 1, 2026
Nonlinear quantum optomechanics in a Fano-mirror microcavity system
Lei Du, Juliette Monsel, Witlef Wieczorek, Janine Splettstoesser
We study a Fano-mirror optomechanical system in the quantum nonlinear regime. In this system, two strongly lossy optical modes hybridize through both coherent and dissipative couplings to form an effective optical mode with a drastically reduced linewidth. This linewidth reduction enables the system to access the single-photon strong-coupling and sideband-resolved regimes simultaneously. We formulate the system dynamics using an effective master-equation approach and benchmark it against quantum Langevin and dressed-state master-equation descriptions. With experimentally realistic parameters, we predict clear quantum signatures, including photon blockade and the generation of mechanical cat states. Our work establishes the Fano-mirror architecture as a promising platform for harnessing single-photon optomechanical nonlinearities for quantum state engineering under achievable experimental conditions.
New article – May 27, 2026
Precision of an autonomous demon exploiting nonthermal resources and information
Juliette Monsel, Matteo Acciai, Didrik Palmqvist, Nicolas Chiabrando, Rafael Sánchez, Janine Splettstoesser
Quantum-dot systems serve as nanoscale heat engines exploiting thermal fluctuations to perform a useful task. Here, we investigate a multi-terminal triple-dot system, operating as a refrigerator that extracts heat from a cold electronic contact. In contrast to standard heat engines, this system exploits a nonthermal resource. This has the intriguing consequence that cooling can occur without extracting energy from the resource on average—a seemingly demonic action— while, however, requiring the resource to fluctuate. Using full counting statistics and stochastic trajectories, we analyze the performance of the device in terms of the cooling-power precision, employing performance quantifiers motivated by the thermodynamic and kinetic uncertainty relations. We focus on two regimes with large output power, which are based on two operational principles: exploiting information on one hand and the nonthermal properties of the resource on the other. We show that these regimes significantly differ in precision. In particular, the regime exploiting the nonthermal properties of the resource can have cooling-power fluctuations that are suppressed with respect to the input fluctuations by an order of magnitude. We also substantiate the interpretation of the two different working principles by analyzing cross-correlations between input and output heat currents and information flow.
New articles – December 13, 2025
Coupling a single spin to the motion of a carbon nanotube
Federico Fedele, Federico Cerisola, Lea Bresque, Florian Vigneau, Juliette Monsel, Jorge Tabanera, Kushagra Aggarwal, Jonathan Dexter, Sofia Sevitz, Joe Dunlop, Alexia Auffèves, Juan Parrondo, András Pályi, Janet Anders, Natalia Ares
Coupling a single spin to high-frequency mechanical motion is a fundamental bottleneck of applications such as quantum sensing, intermediate and long-distance spin-spin coupling, and classical and quantum information processing. Previous experiments have only shown single spin coupling to low-frequency mechanical resonators, such as diamond cantilevers. High-frequency mechanical resonators, having the ability to access the quantum regime, open a range of possibilities when coupled to single spins, including readout and storage of quantum states. Here we report the first experimental demonstration of spin-mechanical coupling to a high-frequency resonator. We achieve this all-electrically on a fully suspended carbon nanotube device. A new mechanism gives rise to this coupling, which stems from spin-orbit coupling, and it is not mediated by strain. We observe both resonant and off-resonant coupling as a shift and broadening of the electric dipole spin resonance (EDSR), respectively. We develop a complete theoretical model taking into account the tensor form of the coupling and non-linearity in the motion. Our results propel spin-mechanical platforms to an uncharted regime. The interaction we reveal provides the full toolbox for promising applications ranging from the demonstration of macroscopic superpositions, to the operation of fully quantum engines, to quantum simulators.
This work is part of the FQxI-funded project Nanomechanics in the solid-state for quantum information thermodynamics.