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Clément Sayrin

@clementsayrin.eurosky.social
250 followers 426 following 46 posts

Associate professor @sorbonne-universite.fr, Quantum Physicists at LKB, traps circular Rydberg atoms

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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2026
We are quite happy to share these results, which make our platform promising for quantum simulation of long-duration phenomena.
static.klipy.com
Minions Cheer and Celebrate
ALT: Minions Cheer and Celebrate
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2026
We show that the duration of the simulation is limited by an interesting phenomenon: the coupling between spin and motional degrees of freedom. Which we observe for the first time with trapped Rydberg atoms.
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2026
To do so, we use circular Rydberg atoms which we laser trap in optical tweezers specially tailored for Rydberg atom: optical bottle beams (or BoBs as we call them, but not the sponge).
A blue torus (representing a circular Rydberg atom) is in the middle a blue shaded area, elongated along the vertical axis, which represents a light beam with a local minimum of intensity, where the atom sits.
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2026
We observe the interaction between two Rydberg atoms, namely a spin-exchange oscillation or flip-flop, akin to the interaction between spin 1/2s. Importantly, we observe these oscillations over more than 60µs and 40 oscillation periods, an order of magnitude longer than the state-of-the-art.
The picture has one main panel and three smaller panels which are zooms into the bigger one. Data points indicate an oscillation of the measured quantity (M on the vertical axis), plotted as a function of a time delta t in micro seconds. A continuous line represents a damped sinusoidal fit the data points and reproduces well the data. The time intervals which correspond to the three smaller panels are indicated by three coloured areas (green, violet, yellow, from left to right).
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2026
A new paper is out from our team at @lkblab.bsky.social, by Andrés Durán-Henández, Gautier Creutzer and all the Rb team @college-de-france.fr @psl-univ.bsky.social @normalesup.bsky.social @cnrs.fr @sorbonne-universite.fr arxiv.org/abs/2609.37766
arxiv.org
Spin-exchange interactions between circular Rydberg atoms over long times
Arrays of neutral atoms excited to Rydberg levels have emerged as one of the most promising platforms for quantum computation and simulation. With the hope to outperform classical devices, the number ...
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ESPCI Alumni @espcialumni.bsky.social · 17/09/2026
La médaille d’or du CNRS est décernée à Jacqueline BLOCH, Ingénieure ESPCI (106e promotion) www.cnrs.fr/fr/presse/le...
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Lab. Kastler Brossel @lkblab.bsky.social · 02/09/2026
Portrait of Tom Chevry, scientific glassblower at LKB! “A unique profession at the intersection of craftsmanship, scientific instrumentation and fundamental research 👉 Portrait by @sorbonne-universite.fr : sciences.sorbonne-universite.fr/portraits/to... @cnrs.fr
sciences.sorbonne-universite.fr
Tom Chevry
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Bon Pote @bonpote.com · 13/07/2026
« C'est tellement criminel. C'est comme si on revivait le Covid, et qu'il n'y avait toujours pas de masque. » Des incendies historiques ravagent la France, de la Drôme jusqu'à Fontainebleau. Voici comment le gouvernement a sabordé nos lignes de défense forestières : bonpote.com/impreparatio...
bonpote.com
Les forêts brûlent, et nous regardons les Canadairs Incendies 2026 : pourquoi la France manque de Canadair et de préparation
Notre enquête sur le manque de moyens et de préparation face aux incendies et sur le fiasco des commandes de Canadairs.
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Clément Sayrin @clementsayrin.eurosky.social · 07/07/2026
I am happy to share that this paper by Matthias Hüls has just appeared on arXiv. It is a result of a collaboration between @lkblab.bsky.social and @fz-juelich.de. We are looking forward future implementations on our experiment. arxiv.org/abs/2607.05216
arxiv.org
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Clément Sayrin @clementsayrin.eurosky.social · 07/07/2026
And thanks to all the participants to have come and visit us in @normalesup.bsky.social, @psl-univ.bsky.social and @sorbonne-universite.fr. It was great to welcome you and to organize the school for you together with Tarik Yefsah.
(Almost) All the participants and mentors stand on the scene for a final goodbye picture.
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Clément Sayrin @clementsayrin.eurosky.social · 07/07/2026
Thanks to our 6 great mentors, Thomas Copie, Óscar Mañas Chambert, Ekaterina Gradova, Antoine Lefebvre, Pedro Minarelli Gaspar and Iliana Tsoni, from @lkblab.bsky.social, @lpens-phys.bsky.social or LPL, to have led their students along a quantum path and for all their help in organising the school!
The students of group 5 conclude their presentations with a slide showing a selfie of the group in the scene in front of all the participants with a thanks to the organizers, mentors and all students. The fire extinguisher applauds.
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Clément Sayrin @clementsayrin.eurosky.social · 07/07/2026
The students themselves then took on the stage to present to their fellows the results of their works with their mentors.
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Clément Sayrin @clementsayrin.eurosky.social · 07/07/2026
Thursday was our fourth and last day of the DigiQ Paris Summer School. Antoine Browaeys opened the day with in-depth lecture about #Quantum Simulation with individual Rydberg atoms.
Antoine Browaeys stands in front of our students and concludes his lectures on quantum simulations with individual Rydberg atoms with a slide questioning "How large can a controlled quantum system be?" with a picture of Schrödinger and his cats, a frontier between quantum and classical worlds, and a picture of thousand of individual laser-trapped atoms
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Clément Sayrin @clementsayrin.eurosky.social · 01/07/2026
After a relaxing trip along the Seine river, to discover the beauties of Paris, the students could enjoy a nice diner in Le Procope, walking along the path of Voltaire, Diderot and d'Alembert.
Our students and mentors have a nice diner together in Le Procope, enjoying French cuisine together. The fire extinguisher was not hungry, it seems.
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Clément Sayrin @clementsayrin.eurosky.social · 01/07/2026
Our third day of the DigiQ Paris Summer School starts with a Bavarian morning. We had the chance to welcome Immanuel Bloch (@lmu.de, MPQ) for his 2nd lecture on Quantum Simulation with Ultracold Atoms and Barbara Kraus @tum.de, teaching our students about Quantum Information and Entanglement Theory.
Immanuel Bloch stands in front of a whiteboard and writes on it to answer questions form our students, while a beautiful picture of Munich is displayed on screen. Barbara Kraus stands in front of our young audience to teach them everything to know about Quantum Information and Entanglement Theory. A slide "LOCC-transformations among bipartite pure states" is displayed on screen. The fire extinguisher attends all the lectures, it will soon become a quantum specialist!
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Clément Sayrin @clementsayrin.eurosky.social · 30/06/2026
This afternoon, Immanuel Bloch, from @lmu.de and MPQ, teaches his first lecture on Quantum Simulation with Ultracold Atoms, guiding the students in understanding cold atom physics and their use in quantum simulators.
Immanuel Bloch stands in front of the students, with the screen on his back showing a nice green picture of atoms organized in a crystal. He also uses a white board to give insights in atom trapping with light, while challenging the students in their physics understanding. The fire extinguisher, on the left, did not know the answer to Immanuel's question, but it is learning.
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Clément Sayrin @clementsayrin.eurosky.social · 30/06/2026
On our second day of the DigiQ Paris Summer School, Saïda Guellati-Khelifa from @lkblab.bsky.social has introduced our students to the fascinating realm of #quantum sensing and presented her experimental activities in LKB. @normalesup.bsky.social @psl-univ.bsky.social @sorbonne-universite.fr
Saïda Guellati stand in front of our wonderful students, and explains them everything about quantum sensing and her experiments in LKB. The screen shows one of her slides giving details about the Zeeman effect. Even the fire extinguisher on the left seems fascinated and understands everything.
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Randall Munroe @xkcd.com · 29/06/2026
720 Ollie xkcd.com/3264/
Comic. [Person with short hair and a skateboard talking to another person, with an image of Person 1 on a skateboard going over a bump with a line with two swirls behind him.] PERSON 1: Something weird I’ve noticed is that if I do a 360 ollie, I land backward. I have to do a 720 to land going forward. [caption] Tony Hawk discovers that he’s a spin-½ fermion.
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Clément Sayrin @clementsayrin.eurosky.social · 29/06/2026
Zaki Leghtas from @lpens-phys.bsky.social @minesparis-psl.bsky.social now teaches everything to know about quantum computing with superconducting circuits.
Zaki Leghtas standing in front of the students, all looking forward to learning everything to know about quantum computing and its superconducting architecture. On the screen, an example of a quantum circuit.
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Clément Sayrin @clementsayrin.eurosky.social · 29/06/2026
Julien Laurat from @quantumnet-lkb.bsky.social @lkblab.bsky.social opens the school with a lecture on quantum memories.
Julien Laurat, standing in front of fascinated students, begins is lecture on Quantum Memories. The title slide is projected on the screen.
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Clément Sayrin @clementsayrin.eurosky.social · 29/06/2026
Today we launch the DigiQ Paris Summer School, co-organized by @normalesup.bsky.social @psl-univ.bsky.social and @sorbonne-universite.fr. We are happy to welcome in ENS 55 students from 14 different European universities for a series of lectures on quantum technologies. www.lkb.fr/en/evenement...
DigiQ Paris Summer School 2026, 29/06-02/07.
Below, the logos of DigiQ, Sorbonne Université and ENS-PSL Université. On the right, a picture of the Eiffel Tower.
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Dr. Serge Zaka @sergezaka.bsky.social · 18/06/2026
[Thread] [1/7] Avec 40-43+°C sur plusieurs jours, nous ne sommes plus sur un simple évènement météorologique, mais un évènement qui aura des conséquences catastrophiques pour la vie animale et végétale. Je pèse mes mots : ce qu'il va se passer en France est sans précédent.
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Lab. Kastler Brossel @lkblab.bsky.social · 03/06/2026
🔬 Exchange of expertise in scientific glassblowing Tom Chevry was hosted at the University of Stuttgart by his counterpart Frank Schreiber. The goal : share experience and know-how, particularly regarding the fabrication of high-precision glass cells 👉 Learn more: www.lkb.fr/en/laboratoi...
lkb.fr
Glass Technology for Quantum Research - Laboratoire Kastler Brossel
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Clément Sayrin @clementsayrin.eurosky.social · 21/05/2026
With a nice feature in Physics. physics.aps.org/articles/v19... Thanks to Sophia Chen.
physics.aps.org
A Quantum Simulator with Circular States
Using atoms in two different highly excited states enables quantum bits that are both long-lived and manipulable.
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Clément Sayrin @clementsayrin.eurosky.social · 21/05/2026
This paper is now out in Physical Review X. We are very happy about it! @lkblab.bsky.social @sorbonne-universite.fr @college-de-france.fr @cnrs.fr @psl-univ.bsky.social @normalesup.bsky.social journals.aps.org/prx/abstract...
journals.aps.org
Nondestructive Optical Readout and Manipulation of Circular Rydberg Atoms
Local quantum nondemolition measurements and optical manipulation of long-lived circular Rydberg atoms are demonstrated by coupling them to an auxiliary array of low-angular-momentum Rydberg atoms.
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Christophe Chartreux @libreavanttout.bsky.social · 18/03/2026
1/30 Pourquoi l’article du Figaro (18 mars 2026) signé Paul-François Paoli est-il une attaque ABSOLUMENT SCANDALEUSE contre Johann Chapoutot, Nicolas Offenstadt, Gérard Noiriel… et contre la recherche universitaires en général. ⤵️
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minimaliste13 @minimaliste13.cpesr.fr · 10/03/2026
Les États-Unis perdent leur seul prix scientifique prestigieux.
theguardian.com
Ig Nobels to move awards to Europe due to concern over US travel visas
Scientific awards – which honor research that makes people laugh and then think – to move away from ‘unsafe’ US
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Dr. Serge Zaka @sergezaka.bsky.social · 07/03/2026
J'ai toujours été prudent quant à l’idée d’une accélération du réchauffement mondial. À partir de maintenant, je ne le serai plus. 1/6
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Les Jours @lesjours.fr · 11/02/2026
🧵🚀 C'est le grand jour! Les Jours fêtent leurs 10 ans. Pour marquer le coup, on lance notre crowdfunding pour créer THE livre de la décennie. On vous explique tout. ⬇️ lesjours.fr/abonneme...
PARTICIPEZ AU FINANCEMENT DU LIVRE ÉVÉNEMENT DES JOURS
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Alexandre delaigue @adelaigue.bsky.social · 16/01/2026
En 1940, Niels Bohr et de Hevesy ont, au péril de leur vie, dissous les médailles des Nobel de deux savants juifs pour éviter qu’elles soient saisies par les nazis. Bohr lui même a vendu sa médaille Nobel aux enchères pour soutenir la défense finlandaise.
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Julien Gossa @juliengossa.cpesr.fr · 15/11/2025
[ #VeilleESR #Parcoursup ] Il vient de se passer un truc extraordinaire : le gouvernement a atteint un de ses objectifs. Celui de baisser la part des néobachliers recevant une proposition dans Parcoursup. C'est sans doute une date historique, le début de démassification éducative, . 🧵
ndicateur 1.5 : Admission dans l'enseignement supérieur
(du point de vue de l'usager)
Unité 2022 2023 2024
(Cible PAP
2024)
2025
(Cible)
2026
(Cible)
2027
(Cible)
Part des néo-bacheliers ayant obtenu au moins
une proposition à la fermeture de Parcoursup
% 94,8 95 94,5 93,5 93,5 93,5Dans ce contexte, la part
de néo-bacheliers recevant au moins une proposition
diminue légèrement (93,5 %, -1,0 point par rapport à 2024).
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
With a special thank to @pasquans2.bsky.social, @agencerecherche.bsky.social, QuanTiP, QICS and @erc.europa.eu.
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
Our wok thus constitutes a key step toward genuine quantum simulation with circular Rydberg atoms. And we are quite excited about it! (14/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
In this picture, the ancilla circular atoms stay in n=52 (small blue torus) if a nearby ancilla is in 45S (large green sphere) but it is excited to n=54 (large red torus) if the ancillae are in their ground state (small red sphere). (13/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
We use a symmetric process to block a microwave transfer between the circular state n=52 and n=54 by exciting an ancilla atom to 45S. This effectively enables an optical control (phase flip and spin flip) of the circular Rydberg state. (12/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
Eventually, the ancilla stays in the ground state if the circular atom is in n=54. It is excited to the 45S Rydberg level if the circular atoms is in n=52. An optical destructive measurement of the state of the ancilla then provides a quantum non-demolition measurement of the circular state! (11/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
If we try and optically excite the ancilla to 45S, the process is impervious to the presence of a circular atom with n=52. However, if the circular atom is in n=54, the strong interaction splits the excitation line and blocks the excitation, in a usual Rydberg blockade mechanism. (10/14)
Population in the ground state after the optical excitation of the ancilla to 45S, as a function of the frequency of the excitation laser. The blue squares are measured with a circular atom in n=52, the red spheres with n=54. A low probability indicates a successful excitation
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
By tuning the electric field, the interaction is made resonant and strong for specific levels: the circular state with principal quantum number n=54 and the low-angular-momentum Rydberg levels 45S, in our work. If the circular atom is in another level (n=52), the interaction is negligible. (9/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
In this work, we make circular Rydberg atoms (blue torus in the picture) interact with other atoms initially in their ground state (red spheres) and excited to low-angular-momentum Rydberg levels. All atoms are laser trapped in the experiment. (8/14)
Three atoms on a line: a red sphere (ground state), a blue torus (circular Rydberg state), and another red sphere. The ground state atoms are trapped in focused Gaussian beam (red beam) and and the circular atom in a bottle beam (blue beam).
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
But these operations are key to quantum simulators! They enable the initialization of the simulator (prepare the atoms in different states) or the measurement of the final state of the simulator (measure the state of every atom). (7/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
The long lifetime of circular Rydberg atoms stems from the absence of optical transition from or to circular levels. The counterpart is that these levels are hard to detect (no direct fluorescence imaging) or to optically manipulate. (6/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
They can also be laser trapped in so-called optical bottle beams, that present a local minimum of intensity. (5/14)
A circular Rydberg atom (blue torus) inside an optical bottle beam (blue beam with an intensity minimum at the place of the atom).
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
Circular Rydberg atoms have the key asset to have a natural lifetime 100 times longer than that of the low-angular-momentum Rydberg levels. This makes them particularly appealing for quantum simulation of the dynamics of interacting spins, in particular slow dynamics such as thermalization. (4/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
Low-angular-momentum Rydberg levels are typically used in quantum simulation and computation because they can be optically excited from the ground state. Arrays of atoms, which interact together when excited to Rydberg levels, simulate, for instance, quantum magnetism. (3/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
In this work, we propose and demonstrate a novel hybrid platform where circular Rydberg atoms are measured and manipulated through their coupling to ancilla atoms, transiently excited to a more common low-angular-momentum Rydberg level. (2/14)
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Clément Sayrin @clementsayrin.eurosky.social · 30/09/2025
I am quite happy to share our latest work from the #Rydberg Atoms team of @lkblab.bsky.social, that just appeared on arXiv, by Yohann Machu and all the Rb team @college-de-france.fr @psl-univ.bsky.social @normalesup.bsky.social @cnrs.fr @sorbonne-universite.fr (1/14) arxiv.org/abs/2509.24691
Four ensembles of atoms arranged on a square. Within every ensemble, there are three atoms. On the two left ensembles, the central atom is depicted with a yellow torus (circular Rydberg level) and the two outer ones with a red sphere (ground state). In the two left ensembles, the central atom is depicted by a small blue torus (circular level), the left atom as a large green sphere (other Rydberg level) and the right atom as a red sphere. All red-sphere atoms are illuminated by a red beam that represents a laser trap.
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Le café pédagogique @cafepedagogique.bsky.social · 02/09/2025
« Et si on imaginait l’école »… en 2042, un roman de Céline Cael et Laurent Reynaud pour rêver l’école www.cafepedagogique.net/2025/09/02/e...
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laydgeur @laydgeur.bsky.social · 15/08/2025
Vous avez sûrement déjà lu que la climatisation aggrave les canicules car l’air chaud rejeté à l’extérieur augmenterait la température des villes de 2 à 3°C. Vérifions ce que disent vraiment les études scientifiques à ce sujet 🧑‍🔬 (lisez jusqu’au bout, car vous allez être 🤯🤯 à la fin) #Thread ⬇️⬇️
Carte de Paris simulation îlot de chaleur
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Christophe Cassou @cassouman40.bsky.social · 12/08/2025
Le Sud de la France subit une #canicule record par sa sévérité(combinaison intensité+durée) & brutalité. ✔quels processus à son origine? ✔pourquoi cet été restera l’un des +frais de ce siècle si on n’accélère pas la décarbonation restant dans l'illusion d'une adaptation sans casse? #fatigue Un fil🧵👇
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Julien Gossa @juliengossa.cpesr.fr · 10/07/2025
[ #VeilleESR #LRU ] Investir dans l’avenir : rebâtir un service public de l’enseignement supérieur Avis du @lecese.fr par @kenzaoccansey.bsky.social Sans doute le plus complet rapport sur l' #ESR à ma connaissance. C'est précis, sourcé, sans dénigrer ni se voiler la face.
lecese.fr
Il est urgent de rebâtir un service public de l'enseignement supérieur | Le Conseil économique social et environnemental
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