Papers by Laurie Letertre
in "Sciences & métaphysiques. Regards croisés", Philippe Huneman et François Papale (Ed.), Éditions Matériologiques, 2025
La mécanique quantique est une théorie physique décrivant le comportement de la matière à petite ... more La mécanique quantique est une théorie physique décrivant le comportement de la matière à petite échelle. Bien qu’elle bénéficie d’un excellent succès empirique, cette théorie soulève un ensemble de questions conceptuelles quant à son interprétation et aux diverses hypothèses et
implications (épistémiques ou métaphysiques) qui y sont associées. Dans le cadre d’une approche réaliste scientifique, la nonlocalité quantique trouve sa source dans la nature elle-même (et non dans notre rapport à celle-ci), et les concepts théoriques tels que la superposition et l’intrication quantiques sont pris en compte dans le développement d’une ontologie adéquate. Un large panorama de possibles descriptions du réel a été proposé sous ces contraintes. Toutes ces descriptions sont nécessairement non-classiques, impliquant une ontologie ou dynamique rompant avec un ou plusieurs principes physiques qui prévalent en physique classique.
L’interprétation de la mécanique quantique dans une perspective réaliste soulève ainsi divers questionnements d’ordre métaphysique, allant de la nature des objets jusqu’à la conception de l’espace et du temps, en passant par celle des lois de la nature et la caractérisation de la causalité.
HAL (Le Centre pour la Communication Scientifique Directe), Mar 10, 2022
arXiv (Cornell University), Jul 20, 2022
Quantum nonseparability is a central feature of quantum mechanics, and raises important philosoph... more Quantum nonseparability is a central feature of quantum mechanics, and raises important philosophical questions. Interestingly, a particular theoretical development of quantum mechanics, called the process matrix formalism (PMF), features another kind of nonseparability, called causal nonseparability. The PMF appeals to the notion of quantum process, which is a generalisation of the concept of quantum state allowing to represent quantum-like correlations between quantum events over multiple parties without specifying a priori their spatiotemporal locations. Crucially, since the PMF makes no assumption about the global causal structure between quantum events, it allows for the existence of causally nonseparable quantum processes. Such processes are said to have an indefinite causal structure. This work aims at investigating the philosophical implications of causal nonseparability, especially for the notion of spatiotemporal relations. A preliminary discussion will first study the formal connection between quantum and causal nonseparability. It will be emphasised that, although quantum processes can be seen as a generalisation of density matrices, the conceptual distinction between the two notions yields significant differences between quantum and causal nonseparability. From there, it will be shown that, depending on the interpretative framework, causal nonseparability suggests some kind of indeterminacy of spatiotemporal relations. Namely, within a realist context, spatiotemporal relations can be epistemically or metaphysically indeterminate. Finally, it will be argued that, in spite of the disanalogies between 1
Studies in History and Philosophy of Science, Oct 1, 2021
Operational frameworks are very useful to study the foundations of quantum mechanics, and are som... more Operational frameworks are very useful to study the foundations of quantum mechanics, and are sometimes used to promote antirealist attitudes towards the theory. The aim of this paper is to review three arguments aiming at defending an antirealist reading of quantum physics based on various developments of standard quantum mechanics appealing to notions such as quantum information, noncausal correlations and indefinite causal orders. Those arguments will be discussed in order to show that they are not convincing. Instead, it is argued that there is conceptually no argument that could favour realist or antirealist attitudes towards quantum mechanics based solely on some features of some formalism. In particular, both realist and antirealist views are well accomodable within operational formulations of the theory. The reason for this is that the realist/antirealist debate is located at a purely epistemic level, which is not engaged by formal aspects of theories. As such, operational formulations of quantum mechanics are epistmologically and ontologically neutral. This discussion aims at clarifying the limits of the historical and methodological affinities between scientific antirealism and operational physics while engaging with recent discoveries in quantum foundations. It also aims at presenting various realist strategies to account for those developments.
Solar Energy Materials and Solar Cells, Feb 1, 2016
Abstract Hybrid solar cells are in sustained development among the photovoltaic (PV) technologies... more Abstract Hybrid solar cells are in sustained development among the photovoltaic (PV) technologies. Molybdenum diselenide (MoSe 2 ) is a promising alternative semiconductor for hybrid PV due to its absorption in the near-infrared spectrum, its good carrier transport and its ability to form 2D structures. Scanning Spreading Resistance Microscopy (SSRM) is used for the electrical characterization of crystalline Nb-doped MoSe 2 . An n-type nature of doping is demonstrated, with local accumulation of dopants in the crystal when substituting Mo atoms by Nb in a 0.01% stoichiometric ratio. On the basis of the SSRM measurements, a band structure for the probe-sample system is proposed. Blends are also prepared with the p-type semiconducting polymer poly(3-hexylthiophene) (P3HT) and the photo-electrical properties of those Nb-doped MoSe 2 :P3HT systems are studied at the nanoscale by PhotoConductive-Atomic Force Microscopy (PC-AFM).
Studies in History and Philosophy of Science
Quantum nonseparability is a central feature of quantum mechanics, and raises important philosoph... more Quantum nonseparability is a central feature of quantum mechanics, and raises important philosophical questions. Interestingly, a particular theoretical development of quantum mechanics, called the process matrix formalism (PMF), features another kind of nonseparability, called causal nonseparability. The PMF appeals to the notion of quantum process, which is a generalisation of the concept of quantum state allowing to represent quantum-like correlations between quantum events over multiple parties without specifying a priori their spatiotemporal locations. Crucially, since the PMF makes no assumption about the global causal structure between quantum events, it allows for the existence of causally nonseparable quantum processes. Such processes are said to have an indefinite causal structure. This work aims at investigating the philosophical implications of causal nonseparability, especially for the notion of spatiotemporal relations. A preliminary discussion will first study the formal connection between quantum and causal nonseparability. It will be emphasised that, although quantum processes can be seen as a generalisation of density matrices, the conceptual distinction between the two notions yields significant differences between quantum and causal nonseparability. From there, it will be shown that, depending on the interpretative framework, causal nonseparability suggests some kind of indeterminacy of spatiotemporal relations. Namely, within a realist context, spatiotemporal relations can be epistemically or metaphysically indeterminate. Finally, it will be argued that, in spite of the disanalogies between 1
The main research programs in quantum gravity tend to suggest in one way or another that most (if... more The main research programs in quantum gravity tend to suggest in one way or another that most (if not all) spacetime structures are not fundamental. At the same time, work in quantum foundations highlights fundamental features that are in tension with any straightforward spacetime understanding. This paper aims to explore the little investigated but potentially fruitful links between these two fields.
Operational frameworks are very useful to study the foundations of quantum mechanics, and are som... more Operational frameworks are very useful to study the foundations of quantum mechanics, and are sometimes used to promote antirealist attitudes towards the theory. The aim of this paper is to review three arguments aiming at defending an antirealist reading of quantum physics based on various developments of standard quantum mechanics appealing to notions such as quantum information, non-causal correlations and indefinite causal orders. Those arguments will be discussed in order to show that they are not convincing. Instead, it is argued that there is conceptually no argument that could favour realist or antirealist attitudes towards quantum mechanics based solely on some features of some formalism. In particular, both realist and antirealist views are well accomodable within operational formulations of the theory. The reason for this is that the realist/antirealist debate is located at a purely epistemic level, which is not engaged by formal aspects of theories. As such, operational ...
Studies in History and Philosophy of Science Part A
Beilstein journal of nanotechnology, 2018
The nanoscale morphology of photoactive hybrid heterojunctions plays a key role in the performanc... more The nanoscale morphology of photoactive hybrid heterojunctions plays a key role in the performances of hybrid solar cells. In this work, the heterojunctions consist of a nanocolumnar TiO surface covalently grafted with a monolayer of poly(3-hexylthiophene) (P3HT) functionalized with carboxylic groups (-COOH). Through a joint analysis of the photovoltaic properties at the nanoscale by photoconductive-AFM (PC-AFM) and surface photovoltage imaging, we investigated the physical mechanisms taking place locally during the photovoltaic process and the correlation to the nanoscale morphology. A down-shift of the vacuum level of the TiO surface upon grafting was measured by Kelvin probe force microscopy (KPFM), evidencing the formation of a dipole at the TiO/P3HT-COOH interface. Upon in situ illumination, a positive photovoltage was observed as a result of the accumulation of photogenerated holes in the P3HT layer. A positive photocurrent was recorded in PC-AFM measurements, whose spatial ma...
Solar Energy Materials and Solar Cells, 2015
Uploads
Papers by Laurie Letertre
implications (épistémiques ou métaphysiques) qui y sont associées. Dans le cadre d’une approche réaliste scientifique, la nonlocalité quantique trouve sa source dans la nature elle-même (et non dans notre rapport à celle-ci), et les concepts théoriques tels que la superposition et l’intrication quantiques sont pris en compte dans le développement d’une ontologie adéquate. Un large panorama de possibles descriptions du réel a été proposé sous ces contraintes. Toutes ces descriptions sont nécessairement non-classiques, impliquant une ontologie ou dynamique rompant avec un ou plusieurs principes physiques qui prévalent en physique classique.
L’interprétation de la mécanique quantique dans une perspective réaliste soulève ainsi divers questionnements d’ordre métaphysique, allant de la nature des objets jusqu’à la conception de l’espace et du temps, en passant par celle des lois de la nature et la caractérisation de la causalité.
implications (épistémiques ou métaphysiques) qui y sont associées. Dans le cadre d’une approche réaliste scientifique, la nonlocalité quantique trouve sa source dans la nature elle-même (et non dans notre rapport à celle-ci), et les concepts théoriques tels que la superposition et l’intrication quantiques sont pris en compte dans le développement d’une ontologie adéquate. Un large panorama de possibles descriptions du réel a été proposé sous ces contraintes. Toutes ces descriptions sont nécessairement non-classiques, impliquant une ontologie ou dynamique rompant avec un ou plusieurs principes physiques qui prévalent en physique classique.
L’interprétation de la mécanique quantique dans une perspective réaliste soulève ainsi divers questionnements d’ordre métaphysique, allant de la nature des objets jusqu’à la conception de l’espace et du temps, en passant par celle des lois de la nature et la caractérisation de la causalité.