Hippolyte Dourdent
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hippoquantum.bsky.social
Hippolyte Dourdent
@hippoquantum.bsky.social
Post-doctoral Researcher @ICFO. Foundations of quantum information.
Auteur de "De l'autre côté du miroir quantique" (Dunod, Avril 2025).
Depuis le Festival Pariscience 2025, où j’ai eu le plaisir de présenter De l’autre côté du miroir quantique. Merci aux organisateur·ices et aux professionnel·les de l’audiovisuel pour ces échanges passionnants, dont les reflets pourraient bien transparaître derrière les écrans👁
📸 : Agathe Goujon
October 17, 2025 at 5:59 PM
Rendez-vous ce week-end dans "La Conversation scientifique" avec @etienneklein.bsky.social sur @franceculture.fr !
J’ai le plaisir d’être l’invité de la prochaine émission, diffusée ce samedi 24 mai à 23h et dimanche 25 mai à 15h. Au programme : un voyage au cœur de l’étrangeté quantique... 🐈👻👀
May 23, 2025 at 3:44 PM
@dulwichquantum.bsky.social you are actually shouted-out in the book 😂
April 24, 2025 at 12:47 PM
J-1 🙀 Pour découvrir comment les scientifiques dessinent littéralement la téléportation, et mettre au clair une bonne fois pour toutes ces histoires de voyages dans le temps, rendez-vous de l'autre côté du miroir quantique le 16 avril (OMG demain !), en librairies.
April 15, 2025 at 4:54 PM
On entend très souvent plein de bêtises sur l'ordinateur quantique et les mondes parallèles... Késako ? Rendez-vous très bientôt pour y voir plus clair 👁 De l'autre côté du miroir quantique, le 16 avril en librairies 👻
April 15, 2025 at 12:43 PM
J-7 🙀
April 9, 2025 at 5:24 PM
J-14 👀 D'où viennent ces fameuses actions fantômes à distance qui épouvantaient Einstein ? Y a-t-il vraiment une « influence instantanée » lorsque l’on mesure un état intriqué ? Pour y voir plus clair, conjurez les 👻 de l'intrication en passant De l'autre côté du miroir quantique 🐈
April 2, 2025 at 5:03 PM
Et non, en physique quantique, le paradoxe EPR n'a rien à voir avec un voyage dans le temps raté... Pour enfin y voir clair derrière les étrangetés que sont le chat de Schrödinger et l'intrication, partez à leur rencontre De l'autre côté du miroir quantique, dans les librairies à partir du 16 avril.
March 20, 2025 at 9:16 PM
Finally, we discuss our results in the light of the debate on the experimental realisation of indefinite causal order, and propose a photonic scheme to implement the SHIFT measurement (and thus "simulate experimentally" the Lugano process 🤓) 14/14
March 3, 2025 at 6:33 PM
We further investigate our results based on the realization of the Lugano process in terms of timedelocalized subsystems. With access to a quantum input, the timedelocalized classical control of CC can be into a quantum control of CC. arxiv.org/abs/2201.11832 13/14
March 3, 2025 at 6:33 PM
How can a QCQC, that is causally nonseparable but can only generate causal correlations, perform a task believed to be intricated with noncausality ? 11/14
March 3, 2025 at 6:33 PM
In our work, we show that despite the equivalence, the SHIFT measurement is also realizable with a more experimentally-friendly process, the quantum switch. arxiv.org/abs/0912.0195 9/14
March 3, 2025 at 6:33 PM
...and that a causal quantum circuit with a SHIFT operation can simulate the action of the Lugano process. However the physical realisability of the latter remains a conondrum. 8/14
March 3, 2025 at 6:33 PM
The Lugano (AF/BW) process, discovered by Araújo, Feix, Baumeler and Wolf, is one of them arxiv.org/abs/1507.01714 Its logical structure resembles that of Borromean rings. Kunjwal and Baumeler have shown that local operations within this process could implement the SHIFT measurement... 7/14
March 3, 2025 at 6:33 PM
But (deterministic) CC without definite causal order nor paradoxes (under free local operations !) exist ! They are the so called "noncausal process functions", that can violate causal inequalities (analoguous with Bell inequalities). arxiv.org/abs/1703.00779 6/14
March 3, 2025 at 6:33 PM
However, such relaxation should be made cautiously: indeed, allowing for CC without causal order could lead to paradoxes such as the grandfather antinomy (where an effect suppresses its own cause) or the information antinomy (where an effect is its own cause). 5/14
March 3, 2025 at 6:33 PM
But what if this impossibility was constrained by the assumption that our communications have to follow a definite causal order ? What if, by relaxing this assumption, we could make the SHIFT operation locally measurable ? arxiv.org/abs/1602.08835 4/14
March 3, 2025 at 6:33 PM
Further details: the SHIFT measurement is a tripartite separable operation that cannot be implemented by local operations with (standard) classical communications (LOCC). A phenomenon known as local indistinguishability or nonlocality without entanglement. arxiv.org/abs/quant-ph... 3/14
March 3, 2025 at 6:33 PM
Our work is based on an equivalence, established by Kunjwal and Baumeler, between the noncausal Lugano process and the SHIFT measurement, exhibiting nonlocality without entanglement. We show that this measurement can also be implemented by a quantum switch. arxiv.org/abs/2202.00440 2/14
March 3, 2025 at 6:33 PM
New paper out 🥳
With Anna Steffinlongo, a brillant PhD student in our group, we show that noncausal classical communications (CC), where all the parties are both in the past and future of each other, can be simulated by a superposition of CC. arxiv.org/abs/2502.15579 1/14
March 3, 2025 at 6:33 PM
February 20, 2025 at 4:26 PM