Andreas Bluhm @hippoquantus.bsky.social · 07/10/2026@markwilde.bsky.social Sorry, hadn't seen that you already found this one 000
Andreas Bluhm @hippoquantus.bsky.social · 07/10/2026So is this one: github.com/openai/math/...github.commath/preprints/The-entropy-photon-number-inequality-September-24-2026 at main · openai/mathContribute to openai/math development by creating an account on GitHub. 100
Andreas Bluhm @hippoquantus.bsky.social · 27/08/2026Understanding this behaviour is an interesting question for future work. Thanks to my coauthors Gereon Koßmann, Martin Sandfuchs, René Schwonnek, Giuseppe Viola and Ramona Wolf for the great collaboration! 000
Andreas Bluhm @hippoquantus.bsky.social · 27/08/2026As expected, we find that this choice matters. Surprisingly, however, it is not always the characterized party extracting the key which achieves the higher key: In the one-sided CHSH protocol the behavior is reversed and the key rate is higher if the untrusted party generates the key. 100
Andreas Bluhm @hippoquantus.bsky.social · 27/08/2026We have applied our methods to various protocols: the BB84 protocol both with and without losses, a qutrit MUB protocol, and protocols based on Bell inequalties such as CHSH and I3322. In particular, we compare the key rate when the characterized and when the uncharacterized party extracts the key. 100
Andreas Bluhm @hippoquantus.bsky.social · 27/08/2026Moreover, we use the Generalized Entropy Accumulation Theorem to derive finite-size security bounds against arbitrary attacks that then can be combined with these numerical methods in order to compute key rates in realistic settings. 110
Andreas Bluhm @hippoquantus.bsky.social · 27/08/2026Happy to announce that our paper on how to compute key rates for one-sided device-independent QKD appeared on the arXiv: scirate.com/arxiv/2608.2.... We provide two extensions of the NPA hierarchy that allow to compute key rates in a QKD scenario with one characterized and one uncharacterized party.scirate.com 120
Andreas Bluhm @hippoquantus.bsky.social · 26/06/2026Our techniques rely on ideas from gate teleportation and measurement based quantum computation, among other areas, bringing several new strategies into NLQC which may be of independent interest. Thanks to Simon Höfer, Alex May, Florian Speelman and Philip Verduyn Lunel for the great collaboration! 000
Andreas Bluhm @hippoquantus.bsky.social · 26/06/2026They even imply the controlled application of any unitary that consists of one Clifford circuit, followed by an arbitrary diagonal unitary and then another Clifford circuit. This implies that many feasible position-verification schemes are equally secure. 100
Andreas Bluhm @hippoquantus.bsky.social · 26/06/2026In particulars, protocols that route a quantum system depending on the classical input imply protocols for controlled single qubit measurements in arbitrary bases and the controlled application of any Clifford unitary. 110
Andreas Bluhm @hippoquantus.bsky.social · 26/06/2026In this work, we focus on the NLQC tasks most relevant for quantum position verifications, namely the ones involving fixed-size quantum inputs and large classical inputs. Among these, we find many new relationships. 100
Andreas Bluhm @hippoquantus.bsky.social · 26/06/2026Our work continues the story we started in scirate.com/arxiv/2505.2..., searching for reductions between NLQC tasks in order to identify those which are hardest, which then could be used as protcols for quantum position verification.scirate.comA complexity theory for non-local quantum computationNon-local quantum computation (NLQC) replaces a local interaction between two systems with a single round of communication and shared entanglement. Despite many partial results, it is known that a cha... 110
Andreas Bluhm @hippoquantus.bsky.social · 26/06/2026I am happy to announce that our newest work on non-local quantum computation (NLQC) has made it to the arXiv: scirate.com/arxiv/2606.2.... For me personally, the main motivation to study these tasks comes from quantum position verification, but it has links to diverse areas such as quantum gravity.scirate.comEquivalence of non-local computation tasks beyond Clifford operationsNon-local quantum computation (NLQC) studies how two collaborating players can implement channels on distributed systems using a single simultaneous round of quantum communication and shared entanglem... 151
Reposted by Andreas BluhmIvan Šupić @quantumsupic.bsky.social · 10/06/2026PhD opportunity in QIT in Grenoble. I am advertising a project through the QuanG2 call, at the interface of nonlocality, self-testing, computationally bounded devices, complexity, and crypto. My project is among the topics offered: phdquantumgrenoble.univ-grenoble-alpes.fr/phd-applicat... 065
Andreas Bluhm @hippoquantus.bsky.social · 31/03/2026Thanks to my collaborators for the great project! 000
Andreas Bluhm @hippoquantus.bsky.social · 31/03/2026We used the theory of robust self-testing to rigorously prove that routed Bell-tests can indeed be used to transfer the underlying optimization problem from the device-independent setting, where it is difficult to approximate, to the device-dependent setting, where it is much easier. 100
Andreas Bluhm @hippoquantus.bsky.social · 31/03/2026New paper! This time, together with René Koßmann and René Schwonnek we looked into using routed Bell tests for device-independent quantum key distribution: scirate.com/arxiv/2603.2...scirate.comDevice independent quantum key distribution with robust self-testsDevice-independent quantum key distribution (DIQKD) provides a model of quantum key distribution with minimal assumptions and highly abstract theoretical building blocks. Although DIQKD frees us from ... 130
Reposted by Andreas BluhmIvan Šupić @quantumsupic.bsky.social · 16/03/2026We are very happy to share that Grenoble will host TQC, one of the most important quantum computing conferences, in 2027! Excited to welcome the community in the heart of the Alpes! tqc-conference.org/2026/2027/ 0258
Andreas Bluhm @hippoquantus.bsky.social · 23/12/2025Thanks to Eric Evert, Igor Klep, Victor Magron and Ion Nechita for the interesting collaboration. I certainly learned a lot! 010
Andreas Bluhm @hippoquantus.bsky.social · 23/12/2025For this, we need to study different types of extreme points for matrix convex sets and uncover a surprising difference between real and complex matrix convex sets. 130
Andreas Bluhm @hippoquantus.bsky.social · 23/12/2025Just in time for the holidays: We have a new paper out about how to use techniques from non-commutative polynomial optimization for measurement incompatibility: scirate.com/arxiv/2512.1...scirate.comInclusion constants for free spectrahedra with applications to quantum incompatibilityBuilding on the matrix cube problem, inclusions of free spectrahedra have been used successfully to obtain relaxations of hard spectrahedral inclusion problems. The quality of such a relaxation is qua... 160
Reposted by Andreas BluhmMarius Lemm @mariuslemm.bsky.social · 10/10/2025New preprint on Hamiltonian Learning of Coulomb potentials and smooth potentials in continuous space arxiv.org/abs/2510.08471 Thanks to my collaborators, @hippoquantus.bsky.social , Tim Möbus, and Oliver Siebert!arxiv.orgLearning Coulomb Potentials and Beyond with Fermions in Continuous SpaceWe present a modular algorithm for learning external potentials in continuous-space free-fermion models including Coulomb potentials in any dimension. Compared to the lattice-based approaches, the con... 031
Andreas Bluhm @hippoquantus.bsky.social · 15/09/2025A big thanks to my coauthors for the great collaboration! Hopefully you enjoy reading the paper as much as we did writing it, despite the approaching QIP deadline :) 010
Andreas Bluhm @hippoquantus.bsky.social · 15/09/2025Again, this result generalizes to k-local Hamiltonians for k>2. While the algorithm is sample- and time-efficient, we don't know if it is optimal, because we lack matching lower bounds so far. So we ask: What is the optimal sample-complexity of certifying Ising Gibbs states? 110
Andreas Bluhm @hippoquantus.bsky.social · 15/09/2025In our final result, we give an algorithm for certifying Ising Gibbs states in trace norm that is both sample and time-efficient, thereby solving a question posed by Anshu hdsr.mitpress.mit.edu/pub/3x2sd8nq...hdsr.mitpress.mit.eduSome Recent Progress in Learning Theory: The Quantum Side 110
Andreas Bluhm @hippoquantus.bsky.social · 15/09/2025This one actually generalizes to k-local and does not need any additional assumptions (e.g. on the degree of the interaction graph). Whether one can find a better algorithm that is also time efficient is an interesting open problem. 110
Andreas Bluhm @hippoquantus.bsky.social · 15/09/2025Secondly, we design an algorithm for learning Ising Gibbs states in trace norm that is sample-efficient in all parameters. Previous approaches learned the underlying Hamiltonian (which implies learning the Gibbs state) but suffered from exponential sample complexity in the inverse temperature. 110
Andreas Bluhm @hippoquantus.bsky.social · 15/09/2025To our knowledge, this is the first nearly-optimal algorithm for testing a Hamiltonian property. A key ingredient in our analysis is the Bonami Lemma from Fourier analysis. Curiously, this Lemma is the reason that our results do not seem to easily generalize to k-local Hamiltonians for k>2. 110
Andreas Bluhm @hippoquantus.bsky.social · 15/09/2025First, we show that certifying an Ising Hamiltonian (checking whether it is identical to some H_0 or far from it) in normalized Frobenius norm via access to its time-evolution operator requires only O(1/ε) evolution time. This matches the known lower bounds up to a logarithmic factor. 110
Andreas Bluhm @hippoquantus.bsky.social · 15/09/2025Happy to announce our new paper "Certifying and learning quantum Ising Hamiltonians" scirate.com/arxiv/2509.1..., together with Matthias C. Caro, Francisco Escudero Gutiérrez, Aadil Oufkir, and Cambyse Rouzé. We are focusing in this paper on 2-local Hamiltonians (so a bit more general than Ising).scirate.comCertifying and learning quantum Ising HamiltoniansIn this work, we study the problems of certifying and learning quantum Ising Hamiltonians. Our main contributions are as follows: Certification of Ising Hamiltonians. We show that certifying an Ising ... 1140
Reposted by Andreas BluhmRobin Kothari @robinkothari.bsky.social · 06/08/2025The QIP 2026 call for papers is out! QIP 2026 will be held in Riga, Latvia from January 24–30, 2026. See you there! qip2026.lu.lv 02815
Andreas Bluhm @hippoquantus.bsky.social · 16/06/2025I am currently looking for a PhD student who would like to work on position-based cryptography. Details can be found here: andreasbluhm.eu/wp-content/u... Please spread the word!andreasbluhm.eu 065
Andreas Bluhm @hippoquantus.bsky.social · 03/06/2025Thanks to Tim Möbus, Tuvia Gefen, Yu Tong, Albert H. Werner and Cambyse Rouzé for the great collaboration! 000
Andreas Bluhm @hippoquantus.bsky.social · 03/06/2025Our main technical tool is a new adiabatic approximation for general Lindbladian evolutions with unbounded generators which should also be helpful elsewhere. For example, we can quantify with it how photon-driven dissipation leads to an effective evolution on the code space for bosonic cat codes. 110
Andreas Bluhm @hippoquantus.bsky.social · 03/06/2025Before, we could either do Heisenberg-limited learning for Bose-Hubbard type models scirate.com/arxiv/2307.0..., or learn arbitrary Hamiltonians with engineered dissipation, but not with Heisenberg scaling scirate.com/arxiv/2307.1.... Our new paper shows that you can have the best of both worlds.scirate.comHeisenberg-limited Hamiltonian learning for interacting bosonsWe develop a protocol for learning a class of interacting bosonic Hamiltonians from dynamics with Heisenberg-limited scaling. For Hamiltonians with an underlying bounded-degree graph structure, we can... 100
Andreas Bluhm @hippoquantus.bsky.social · 03/06/2025New day, new paper, this time on Heisenberg-limited Hamiltonian learning for continuous variable systems with engineered dissipation: scirate.com/arxiv/2506.0.... The idea is to use strong dissipation to restrict the Hamiltonian evolution onto a convenient subspace where we can learn it.scirate.comHeisenberg-limited Hamiltonian learning continuous variable systems via engineered dissipationDiscrete and continuous variables oftentimes require different treatments in many learning tasks. Identifying the Hamiltonian governing the evolution of a quantum system is a fundamental task in quant... 170
Andreas Bluhm @hippoquantus.bsky.social · 02/06/2025Thanks to my PhD student Simon Höfer, Alex May, Mikka Stasiuk, Philip Verduyn Lunel and @henryyuen.bsky.social for the great collaboration! And congratulations to Simon for his first paper. 030
Andreas Bluhm @hippoquantus.bsky.social · 02/06/2025In the longer term, our aim is to be able to put NLQC tasks into classes of equally hard problems, like complexity classes. This would allow us to identify the hard NLQC problems that we would like to use for quantum position verification, because they are hard for attackers to solve. 120
Andreas Bluhm @hippoquantus.bsky.social · 02/06/2025In particular, we have shown that two protocols for quantum position verification, the f-route and the f-measure protocol, are equally secure, i.e., if you can attack one, you can attack the other. This gives the first subexponential upper bound on the entanglement needed to attack f-measure. 120
Andreas Bluhm @hippoquantus.bsky.social · 02/06/2025We have a new preprint out on the topic of quantum position verification and non-local quantum computation (NLQC): scirate.com/arxiv/2505.2.... We are comparing different NLQC tasks and find reductions between them (in the sense of if I can do task 1, then I can do task 2 with an extra EPR pair).scirate.comA complexity theory for non-local quantum computationNon-local quantum computation (NLQC) replaces a local interaction between two systems with a single round of communication and shared entanglement. Despite many partial results, it is known that a cha... 171
Reposted by Andreas BluhmIvan Šupić @quantumsupic.bsky.social · 20/05/2025CNRS is opening a call for CPJ (chair de professeur junior), a kind of tenure track with very good conditions. One position is open for quantum computing, and one of the hosting labs is LIG in beautiful Grenoble! The application deadline is July 14th. www.ins2i.cnrs.fr/fr/cnrsinfo/...ins2i.cnrs.frListe des postes de chaires de professeur junior de CNRS Sciences informatiques 2025Le CNRS recrute des chercheurs et chercheuses sur des Chaires de professeur junior (CPJ) dans plusieurs domaines relatifs aux sciences informatiques. 033
Andreas Bluhm @hippoquantus.bsky.social · 29/04/2025Thanks to my coauthors for the great collaboration! 000
Andreas Bluhm @hippoquantus.bsky.social · 29/04/2025To unite these different phenomena, we consider multimeters, i.e., collections of measurements. Many of them, e.g., compatible measurements, classical simulations of measurements, or the compression of measurements can be viewed as factorizations of these multimeters through different state spaces. 100
Andreas Bluhm @hippoquantus.bsky.social · 29/04/2025If you are interested in quantum non-classicality, you might enjoy our new preprint: scirate.com/arxiv/2504.1.... In it, we use the framework of general probabilistic theories to connect different forms of non-classicality, in particular measurement incompatibility, steering, and Bell non-locality.scirate.comFactorization of multimeters: a unified view on nonclassical quantum phenomenaQuantum theory exhibits various nonclassical features, such as measurement incompatibility, contextuality, steering, and Bell nonlocality, which distinguish it from classical physics. These phenomena ... 160
Reposted by Andreas BluhmMarkus Heinrich @markusheinrich.bsky.social · 06/03/2025FZ Jülich is hiring a PhD candidate which will be co-supervised by myself at U Cologne. Interested in benchmarking/characterisation, in working in a highly collaborative environment, and want to see your work being used in experiments? Consider applying! www.fz-juelich.de/en/careers/j...fz-juelich.dePhD position – Sample-efficient quantum gate calibration based on quantum optimal controlThe Peter Grünberg Institute for Quantum Control (PGI-8) at the Forschungszentrum Jülich specializes in novel optimization strategies for emerging quantum technologies. These emerging technologies aim... 063
Reposted by Andreas BluhmMarius Lemm @mariuslemm.bsky.social · 03/03/2025If you're an undergraduate student interested in the mathematics of quantum physics and general relativity, consider the Tübingen International M.Sc. Program in #MathematicalPhysics www.math.uni-tuebingen.de/en/mmp Opens for applications todaymath.uni-tuebingen.deMaster in Mathematical Physics 053
Reposted by Andreas BluhmQuantiki @quantiki.bsky.social · 26/02/2025Summer school Mathematics and Physics of Quantum Computing and Quantum Learning, on the island of Porquerolles, France www.quantiki.org/conference/m...quantiki.orgMathematics and Physics of Quantum Computing and Quantum Learning | Quantiki 033
Reposted by Andreas BluhmQMATH @qmath-copenhagen.bsky.social · 25/02/2025PhD Opportunities – Quantum Algorithms for Quantum Chemistry. Join the Quantum for Life Center at the University of Copenhagen as PhD student! Work on quantum algorithms for chemistry with Prof. Matthias Christandl & co-supervision by Prof. Markus Reiher (ETH Zurich). 1/nmath.ku.dkVacant positions – University of Copenhagen 133
Reposted by Andreas BluhmIoannis Kontoyiannis @kontoyiannis.bsky.social · 18/02/2025⏰ Beyond IID 2025 Conference just announced sites.google.com/view/beyondi... 093
Reposted by Andreas BluhmChristoph Hirche @christophhirche.bsky.social · 13/02/2025We're looking for a new addition to our group. Drop me a message if you're interested! 083
