I am a postdoctoral researcher at IQOQI Vienna (Institute for Quantum Optics and Quantum Information), part of the Austrian Academy of Sciences, where I work in the group of Markus Müller. I am also affiliated with the Basic Research Community for Physics (BRCP), an international association promoting collaborative and non-dogmatic approach to fundamental research.
My work touches on topics in quantum foundations, quantum information, mathematical physics, and the foundations of spacetime. I develop tools and frameworks that lie at the intersection of Quantum Theory and Relativity, engaging directly with the deepest foundational questions.
I am also dedicated to helping build a healthy research community centered around inspiring collaborations instead of anxious competition, shared curiosity instead of hyper-productivity, and true friendship instead of corporate culture.
Started new position as Postdoctoral Researcher at IQOQI Vienna
Research
I am building a new mathematical and conceptual foundation for relativistic quantum physics — one that puts reference systems at the centre, bridging quantum mechanics and relativity in a novel and powerful way.
The main thread underlying most of my research is an attempt at reconciling Quantum Theory with Relativity by insisting on the principles of 1) operationality, emphasizing the observable content of the frameworks and weakening ontological commitments, and 2) relationality, understood as the fundamental insight, akin to the principle of relativity, that physical observables need always be defined with respect to a reference. The angle I have chosen is closer in spirit to the idea of relativizing quantum theory than to quantizing gravity. It begins by extending the formalism of quantum theory by grounding it in operationality and relationality, to then investigate how this extended framework behaves in the presence of relativistic symmetry structures. This philosophy opens up new ways in which relativistic and quantum physics may peacefully coexist. Developing the formal machinery in which these ideas can be firmly grounded and investigating the rich interplay between the mathematical structures involved is a vital and important part of my research.
Concretely, I now develop Relational Quantum Field Theory (RQFT), which is an emerging framework based on the operational approach to Quantum Reference Frames (QRFs) that I helped build. It aims to redefine the mathematical and conceptual foundations of Quantum Field Theory. This formalism is built with the capacity to encompass the dynamical nature of spacetime geometry. The main mathematical tool that allows the extension of the existing theory beyond flat and fixed background spacetime is the theory of integration of operator-valued functions with respect to operator-valued measures that I am constructing. The programme ultimately targets one of the central open problems in theoretical physics: a mathematically rigorous and conceptually coherent foundation for relativistic quantum physics, with quantum gravity as the horizon.
The Big Picture
Conceptual
Measurable quantities can only be defined relative to the measurement setup. In Relativity, they are defined with respect to imagined rods and clocks that are then abstracted away into purely geometrical notions of local coordinate systems or tetrad fields. But in fact, such rods and clocks are practically needed as physical systems for the observations to take place and to be meaningful. Combining this reasoning with a premise that ultimately all physical systems are describable within the quantum formalism, the idea of a quantum reference frame arises. One then aims at constructing relational, i.e., relative to a quantum frame, observables that ought to be invariant with respect to joint transformations of the reference and the system — they capture the relation between the two.
Mathematical
Geometric structures of General Relativity are naturally and efficiently captured in the language of Principal Bundles. The formalism of Quantum Theory is based on convex theoretic and algebraic structures associated to Hilbert spaces. From the operational perspective on the latter, the obvious link with the former is by taking sample spaces of quantum observables (positive operator-valued measures, POVMs) to admit the structure of Principal Bundles, and demand coherence with group actions in a form of covariance conditions. Systems with such observables are understood as Quantum Reference Frames; they are quantum systems with a built-in geometrical notion of localization and orientation. Other quantum systems should be described relationally, relative to them.
This line of research can be divided into the following themes, bundling together interdependent questions.
Quantum Reference Frames
How to coherently describe quantum systems relative to each other? Can different such relative descriptions be coherently related to one another? What role(s) do symmetry structures play?
Relational Quantum Field Theory
Can we construct a new — alternative to algebraic and distributional — mathematical and conceptual basis for modelling quantum systems in coherence with relativistic principles?
Generally Relativistic Quantum Theory
Can the relational approach to relativistic quantum physics transcend the realm of fixed background geometry, allowing for a dynamical interplay between quantum matter and spacetime?
Operator-valued Integration
Can we construct a rigorous mathematical theory of integration for general operator-valued functions with respect to positive operator-valued measures?
Other Foundational Questions
Rethinking foundations of relativistic quantum physics is not my only research interest. Besides that, I am interested in various other foundational questions, such as trying to understand the quantum formalism by reconstructing it from first principles, how subsystems can coexist and what independence means, or whether spacetime is fundamental or rather emergent.
Operational Reconstruction
Can we understand the formalism of single quantum systems as inevitable from a purely operational perspective? Can we single it out as the only one describing measurable correlations? Are principles of relativistic information processing necessary or sufficient for such a derivation?
Subsystems Independence
What does it mean for two systems to be part of a larger one? Why quantum systems compose the way they do? When are (sub)systems independent? Can these questions be addressed in the context of relativity and indefinite causality? What is a system anyway...?
Spacetime Emergence
Can spatiotemporality and dynamics be understood as emerging from some deeper underlying structures? Are the notions of space and time fundamental to how humans theorize, or can — and should — we transcend them? How...?
Wigner's Friend Operationally
What does it mean for two observers to have incompatible accounts of the same measurement event? Can an operational approach — grounded in quantum reference frames and relational observables — dissolve the apparent paradox?
I welcome Master's students interested in working on foundational topics — feel free to reach out!
Roadmap
My research unfolds in overlapping stages. Here is a precise account of where things stand.
Early Work
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Explaining the Poisson structure of constraints in General Relativity
published
This is my first paper, written during the first year of my PhD when I was part of the Lichtenberg Group in Bonn. It lies on the sidelines of my main research now but makes me proud as an early, single-authored achievement. In this work I addressed a long-standing issue: the origin of the Poisson bracket structure of the dynamical constraints that is universal among almost all models in General Relativity. I provide an elegant solution to this old puzzle by proposing a simple and compelling compatibility requirement from which the desired structure follows automatically.
Mathematical foundations for Rovelli's Relational Quantum Mechanics
published
My first encounter with relational ideas in foundations of quantum physics was Relational Quantum Mechanics proposed by Carlo Rovelli. Frustrated by the lack of firm mathematical grounding of these fascinating ideas, together with some participants of the first Sejny workshop we set ourselves the task of providing such rigorous underpinning. We managed to formalize the notion of a net of relative facts and investigated how the usual Hilbert space formalism for quantum systems can be seen as emerging from what we called 'fact-nets'.
Operational framework for Quantum Reference Frames
published
The central result of my PhD work — fully elaborated in the comprehensive paper with Carette and Loveridge (Quantum, 2025) — is a rigorous, measurement-theoretic foundation for quantum reference frames and their transformations. A quantum reference frame is defined as a quantum system admitting covariant observables: positive operator-valued measures (POVMs) that transform covariantly under a symmetry group. The relative observables between frame and system are then invariant under joint transformations, giving a precise operational meaning to frame-dependent observables. Frame transformations — the analogue of coordinate changes — are derived from first principles rather than postulated, and are shown to be quantum channels. The framework applies to a large class of symmetry groups, unifies and vastly generalizes several previously disparate results in the literature. At the time, this was by far the most rigorous formalization of the idea of a quantum reference frame applicable in such generality. The results about frame transformations scrutinize the core intuitions underpinning much of the competing approaches in the field from an operational standpoint.
Quantum Reference Frames on finite homogeneous spaces
published
A companion paper to the main QRF framework, where frames are based on groups, studying quantum reference frames on finite homogeneous spaces. It provides explicit structural results in this restricted setting to serve as a stepping stone towards tackling frame on general homogeneous spaces.
Towards Relational Quantum Field Theory — research statement
This is an early manifesto providing a bird's-eye view of the big ideas about constructing novel foundations for relativistic quantum physics by extending the operational approach to quantum reference frames.
Relational Quantum Field Theory for scalar fields on Minkowski spacetime
preprint
The RQFT programme aims to rebuild the mathematical and conceptual foundations of quantum field theory from the ground up using operational quantum reference frames. The first paper in the series, joint with Samuel Fedida, treats free scalar fields in Minkowski spacetime: Poincaré-covariant quantum frame observables give rise to relational local observables; the resulting local observable algebras satisfy all core axioms of Algebraic QFT (isotony, Poincaré covariance, approximate causality, the time-slice axiom); and vacuum expectation values reproduce the Wightman function properties.
This is the project I find most pressing due to its far-reaching consequences for the whole Relational QFT programme, and its mathematical depth. Standard integration theories (Bochner, Pettis) break down when both the integrand and the measure are operator-valued — a situation that arises naturally when orientation-dependent operators (operator-valued functions) are integrated against quantum frames (POVMs). I developed a self-contained theory showing that, under mild assumptions, the integral of an operator-valued function with respect to an operator-valued measure yields a unique bounded operator on the tensor product Hilbert space. This fills the foundational mathematical gap needed to extend the relativization map, lying at the heart of the operational QRF framework, from groups to general homogeneous spaces and principal bundles. After discussing this work with other mathematicians, some gaps and possible extensions were discovered; the preprint will soon be updated and submitted for publication as joint work with Yui Kuramochi, who is helping me bring this work to its final form.
Relational Quantum Field Theory for spinor fields in Minkowski spacetime
in preparation
This is a natural although highly nontrivial extension of the results achieved for scalar fields to the realm of spinor fields (still on flat background spacetime). It's a continuation of joint work with a Cambridge PhD student Samuel Fedida.
Subsystems independence
in preparation
During our investigations in the EmerGe collaboration we delved deep into the difficulty of defining subsystems and an appropriate notion of independence in the context of quantum gravity. We are now working on a substantial review paper which, relying heavily on algebraic methods, discusses the definitions of subsystems and independence across theories — from classical mechanics through quantum theory, all the way to quantum field theory — to then evaluate how they stand in the context of quantum gravitational proposals. This will be a unique and much-needed, widely accessible presentation of a fairly complex and mathematically involved subject of critical importance. Such contribution is only possible thanks to the diverse background and expertise of the collaboration's members.
Categorical structure of relativization
preprint, finalising
The relativization operation — mapping system observables to relational observables defined with respect to a quantum frame — is not merely an ad hoc construction but a functor: it is compatible with the compositional structure of physical systems in a mathematically precise sense. This embeds the QRF programme into the language of category theory, clarifying how different relational descriptions cohere and compose. This work is a first account of the categorical structures underlying quantum reference frames; a preprint is available online, to be sent for publication after minor adjustments.
Using the general theory of operator-valued integration I will extend the relativization procedure to quantum reference frames modelled on principal bundles and address quantum reference frames on this level of generality. This will be another hugely important stepping stone towards a relational unification of quantum and relativistic theories.
Relational Quantum Gauge Theory
Having established QRFs on principal bundles I will be ready to construct relational, measurement-theoretic models for quantum gauge theories, rewriting the foundations of the subject that lies at the heart of the Standard Model, which is the foundation of our current understanding of particle physics.
Inevitability of relativization
Again relying heavily on operator-valued integration theory, I will address perhaps the deepest conceptual question in the foundations of the operational approach to Quantum Reference Frames: why the relativization map exists and could not be replaced by a different one.
Relational measurement schemes
Quantum Measurement Theory calls for integration with the relational principles described above. This project aims to fill that gap by developing a general theory of relational measurement schemes applicable to relativistic scenarios.
Operational account of the Wigner's Friend scenarios
Traditional accounts of the Wigner's Friend paradox (and extended versions of it) do not do justice to the principles of operational quantum physics or take into account the relationality of observable events. The operational Quantum Reference Frames framework is in a unique position to address these shortcomings and provide a resolution of this long-standing paradox.
Long-term Plans (4–6 years)
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Relational Quantum Field Theory on curved spacetimes
Spacetime geometry can be naturally encoded in a Lorentz principal bundle over the spacetime manifold. Placing Quantum Reference Frames on this bundle unlocks a treatment of quantum fields on curved backgrounds making an extension of the whole Relational QFT programme to this domain possible.
Generally Relativistic Quantum Theory
The Lorentz principal bundle is a subbundle of the frame bundle, and the way the two interact encodes the metric tensor. Placing Quantum Reference Frames on the frame bundle allows for a relational treatment of quantum fields on spacetimes without predefined spatiotemporal geometry, making room for a completely novel, relational formulation of the Einstein Equation in the quantum domain.
Operational reconstruction of Quantum Theory
What is measured in experiments are correlations between the parameters of the measurement setup and the outcomes. Such correlations decompose into preparation and measurement channels — this is true of classical systems, quantum systems, and more general probabilistic models (GPTs). The reconstruction idea is to find suitable constraints on simultaneous decompositions of such correlations that would single out Quantum Theory among viable alternatives.
Community & Collaborations
I value friendship, collaboration and the scientific community and I am invested in improving the academic environment, at least "locally". For these reasons, I am part of the following initiatives.
BRCP
Active Member
Basic Research Community for Physics
An independent international association of scientists promoting open-minded approaches to fundamental questions in physics, fostering cooperative rather than competitive scientific research.
Research Collaboration: "Emergent Geometries — investigating phenomenological signatures that could experimentally constrain different approaches to spacetime emergence."
A series of yearly summer schools (2021–23) for junior researchers in Physics, Mathematics, and Philosophy, fostering interdisciplinary dialogue on foundational questions.
Research group of Markus Müller at IQOQI Vienna, working on the foundations of quantum theory, quantum information, and the interplay between quantum mechanics and spacetime.
PhD candidate at DAMTP, University of Cambridge, working on Relational Quantum Field Theory. I collaborate closely with Samuel on the RQFT programme, co-authoring the first paper in the series on scalar fields.
Develops a relational formalism for scalar quantum fields building on the operational QRF framework, as the first paper in a series constructing the full Relational QFT programme.
Gives a rigorous and comprehensive operational framework for quantum reference frames and their transformations, grounded in the measurement-theoretic formalism of quantum theory.
Operator-valued Integration and Quantum Reference Frames
Systematically develops integration theory for operator-valued functions and measures — filling a foundational gap in the mathematical underpinnings of the QRF framework — and applies it to construct general relativization maps.
Introduces the conceptual and mathematical foundations for Relational Quantum Field Theory, identifying the core structural principles and the key technical challenges the programme must address.
Quantum Reference Frames on Finite Homogeneous Spaces
J. Głowacki, L. Loveridge, J. Waldron
International Journal of Theoretical Physics 63, 137 (2024)
Studies quantum reference frames on finite homogeneous spaces, providing explicit worked examples and structural results that ground the general theory in concrete, tractable cases.
Shows that the relativization map has natural functorial properties, embedding the quantum reference frames programme into the language of category theory.
Operational Quantum Frames: An Operational Approach to Quantum Reference Frames
The most comprehensive single account of the operational QRF formalism: from axiomatic foundations to frame transformations, with an extensive outline of the research programme it opens. Best starting point for newcomers to the framework.
Fact-nets: Towards a Mathematical Framework for Relational Quantum Mechanics
P. Martin-Dussaud, T. Carette, J. Głowacki, V. Zatloukal, F. Zalamea
Proposes fact-nets as a rigorous mathematical foundation for Relational Quantum Mechanics, formalizing the network of observer-relative quantum events in a precise mathematical framework.
Inevitability of the Poisson Bracket Structure of the Relativistic Constraints
