News
New publication in Journal of Physics A
In our new publication in the Journal of Physics A: Mathematical and Theoretical , we point an novel relationships between infinite-dimensional holographic codes - written as asymptotic limits of tensor networks - and the theory of operator algebras following von Neumann. This collaboration of physicists and mathematicians between Caltech and the University of Pennsylvania and our group in Berlin both illuminates the algebraic structure of holographic tensor networks and develops practical models in which the emergence of so-called type II factors can be studied, generalizing the simple Araki-Woods construction. Physically, it also sharpens the idea that the entanglement of gravitational degrees of freedom in holography, which is often associated with the algebras acting on the tensor network states that we study here, have a fundamental type II form. Link to publication: https://iopscience.iop.org/article/10.1088/1751-8121/ae0edd
Oct 31, 2025
Second publication in Quantum
Our second group publication in the journal "Quantum" within three weeks: The article "Far from Perfect: Quantum Error Correction with (Hyperinvariant) Evenbly Codes" introduces a new class of holographic qubit codes. In collaboration with TU Delft (The Netherlands), the University of Queensland (Australia), and OIST (Japan) we propose these "Evenbly codes" - named after a landmark 2017 paper by Glen Evenbly on "hyper-invariant" tensor networks - to describe both aspects of holographic dualities under bulk quantum corrections as well as subsystem qubit codes with potentially practical features. In particular, we show that different ways of gauge-fixing the bulk state lead to an encoding of bulk (logical) in boundary (physical) qubits that can protect well against different types of physical quantum errors. This applies ideas from pure high-energy theory on holographic dualities to practical questions of realizing quantum computation in noisy environments. Link to publication: https://quantum-journal.org/papers/q-2025-08-08-1826/
Aug 11, 2025
New publication in Quantum
Our work "Critical spin models from holographic disorder" studies the boundary symmetries of discrete-holographic models. We find that these symmetries, analytically described by a "multi-scale quasicrystal ansatz" (MQA), form a new type of disordered critical phase in spin chains, with criticality preserved both in the interacting and non-interacting regime. These results show that discrete holography can lead to us to finding new phases of quantum many-body systems. Link to publication: https://doi.org/10.22331/q-2025-07-22-1808
Jul 22, 2025
New publication in Nature Communications
In our publication "Overlapping qubits from non-isometric maps and de Sitter tensor networks" in Nature Communications, we discuss the effects of gravitational corrections on the Hilbert space of semiclassical, effective field theory. We show that these corrections are closely related to an established concept in quantum information theory: Overlapping qubits, which appear when compressing operators from a larger Hilbert space into a smaller one. We demonstrate the usefulness of this relation by constructed overlapping qubits for a model of expanding spacetime, in which corrections to the effective operators closely resemble effects expected from gravity. Link to publication: https://doi.org/10.1038/s41467-024-55463-9
Jan 27, 2025