Quantum Information at ULB

Quantum speed limits for information and coherence doi.org/10.1088/1367-2… w/ Brij Mohan & Arun K Pati We determine speed limits on informational measures, namely von Neumann entropy, maximal information, & coherence of quantum systems evolving under dynamical processes.

Fundamental limitations on the device-independent #quantum conference key agreement journals.aps.org/pra/abstract/1… w/ Karol Horodecki & Marek Winczewski. We provide bounds on the optimal rate at which trusted users can distill conference key against quantum adversary.

Entanglement-assisted communication protocols are analyzed, deriving optimal bounds for the correlations established between two parties that exchange messages in the presence of noise. @iqoqivienna @ULBruxelles go.aps.org/3Fp4o40

Controlling the order of quantum operations in a circuit with another quantum system uncovers new types of noncausal computations. @InstitutNeel @inria_grenoble @QuantInfoULB @hippoquantum go.aps.org/3DkKqH0

New preprint “Entanglement in prepare-and-measure scenarios: many questions, a few answers” from Jef Pauwels, Armin Tavakoli, Erik Woodhead and Stefano Pironio now on arXiv: arxiv.org/abs/2108.00442 #quantum

Our work gives quantum #thermodynamical meaning to the majorization relation on the set of nonincreasing vectors due to Hoffman. The prospect of this work is a general resource-theoretical framework for the extractable work via #quantum operations going beyond thermal operations

Upper bounds on device-independent quantum key distribution (DI-QKD) rates in static and dynamic scenarios. arxiv.org/abs/2107.06411, w/ @Eneet1 and Karol Horodecki. #Quantum #Cryptography #DIQKD

We introduce QPV protocols that are practically secure: they only require single-qubit states from each of the verifiers, yet their security is broken if adversaries sharing impractically large number of entangled qubits employ teleportation-based attacks doi.org/10.1088/1367-2…

New paper published in Quantum: “Quantum advantage from energy measurements of many-body quantum systems” by Leonardo Novo, @queenofquanta and @RaulGarciaPatr1 quantum-journal.org/papers/q-2021-…

New preprint "Correlations in entanglement-assisted prepare-and-measure scenarios" by Armin Tavakoli, Jef Pauwels, Erik Woodhead and Stefano Pironio now on arXiv (arxiv.org/abs/2103.10748). #quantum

A deeper investigation shows how the shapes of an operational theory's state and effect spaces determine whether the predictions of the theory admit of a classical (noncontextual) explanation. @quaintum @eliewolfe @Perimeter @QuantInfoULB @ictqt bit.ly/2ZQkeBD

New press release by Ognyan Oreshkov at QUIC: “Quantum causal loops” (eurekalert.org/pub_releases/2……) via @EurekAlert about joint work with Jonathan Barrett and Robin Lorenz from @OxfordQuantum, published this week in @NatureComms. #physics #quantum #quantuminformation #causality

Partial order on passive states & Hoffman majorization in quantum thermodynamics: arxiv.org/abs/2012.11626 w/ @singhuttam & Nicolas Cerf. Our main goal in this work is to explore a theory of quantum thermodynamics in the absence of a thermal heat bath.

Recent preprint by Leonardo Novo (QuIC, @ULBruxelles) & Sofia Ribeiro (@DurhamQlm) explores how Floquet engineering can be used in the continuous-time quantum walk framework to simulate graphs with increased connectivity and/or complex couplings. arxiv.org/abs/2012.00448

Link to the full paper: arxiv.org/abs/1911.07306 Link to the long talk: youtube.com/watch?v=NzBmyd…

Paper titled "Quantum Speedup for Graph Sparsification, Cut Approximation and Laplacian Solving", by Simon Apers (QuIC ULB, CWI & INRIA Paris) & Ronald de Wolf (QuSoft, CWI) will be presented at the 61st Annual IEEE Symposium on the Foundations of Computer Science (#FOCS2020).

Our paper on joint measurability structures realizable with qubit measurements is now published @PhysRevResearch journals.aps.org/prresearch/abs… #quantum #paper #measurement #incompatibility

Joint measurability structures realizable with qubit measurements: Incompatibility via marginal surgery, Nikola Andrejic and Ravi Kunjwal (@quaintum) @QuantInfoULB @Perimeter #quantum #quantuminformation go.aps.org/35JcDr5

They provide a continuous-time quantum walk based algorithm that can find a marked vertex on any ergodic, reversible Markov chain quadratically faster than classical random walks.

Paper titled "Finding a marked node on any graph via continuous-time quantum walks" by @shantanav_c, Leonardo Novo and Jérémie Roland has been published in @PhysRevA. journals.aps.org/pra/abstract/1…