Bruno is awarded one of the COFUND postdoctoral fellowships from The Barcelona Institute of Science and Technology (BIST). Congratulations!


First 2D and 3D MOTs after the replacement of the 2D MOT chamber!


Leticia is today in Munich, visiting Fabian Heidrich-Meisner. There, she gives a talk on our latest results, and has also interesting discussions on the possibilities opened by potassium for the study of interacting bosonic Hofstadter strips.


Many things happen today! Julio, Cesar, Anika and Bruno install the new magnet/coil/heating box around the new glass cell 2D MOT. It should allow us to generate all magnetic fields required, and at the same time keep a more stable potassium vapour pressure. In the mean time Leticia visits Heidelberg, where she has many interesting lab visits and discussions, and also gives a talk on our droplet experiments.


Our paper “Quantum liquid droplets in a mixture of Bose-Einstein condensates” appears in today’s issue of Science, together with a Perspective article by Igor Ferrier-Barbut and Tilman Pfau.


“Liquids that are less dense than an ideal gas”, a nice summary of our droplet experiments from Physics Today.


Anika Frölian joins the group as PhD student. Welcome to the QGE, Anika!


Our Plan Nacional project “QuDROP: Quantum droplets in attractive Bose-Bose mixtures” has been selected for funding! This should allow us to make a number of upgrades in our apparatus, including a professional microscope objective and a more powerful optical dipole trap laser. A really nice Christmas present!


QGE group season’s greetings: Feliz Navidad y Próspero 2018!
Thanks, Cesar, for yet another artistic work!
QGE Seasons greetings 2017


We finally get nice potassium absorption in our new 2D MOT chamber!
WhatsApp Image 2017-12-18 at 09.39.58


Today is the ICFOday 2017. Bruno gives a talk, Cesar presents a poster and Julio gives lab tours to ICFOnians interested in learning more about our research. In the mean time, Leticia is in Madrid where she gives an invited talk in the Young Researchers Meeting of the Nicolás Cabrera Institute of the UAM. It is a nice occasion to get an overview of the research that goes on at the INC, and also to visit the low-temperature labs afterwards. Thanks for the invitation!
WhatsApp Image 2017-12-16 at 11.31.43INC-2017


Our paper “Quantum liquid droplets in a mixture of Bose-Einstein condensates” is published today ahead of press in Science!!! Check here to see the online version!

WhatsApp Image 2017-12-18 at 16.15.50


Leticia is this week in Hong Kong, attending the conference Frontiers in Cold Atom Physics where she gives a talk on our droplet results. Thanks a lot to the Hong Kong colleagues for the invitation and the great discussions.


Mariusz Gajda (Institute of Physics, Polish Academy of Sciences) is this week at ICFO, and gives today a really interesting talk on quantum droplets in Bose-Fermi mixtures. Thanks for the visit and the discussions, Mariusz!


The complete group is these days in Hamburg, attending the annual meeting of the FOR project. Cesar gives a talk, Julio presents a poster and we all have interesting discussions with the Hamburg, Munich, Dresden, Palaiseau and Frankfurt groups. Thanks a lot to the Hamburg people for the organization and the great labtours!


Tigrane Cantat-Moltrecht (Laboratoire Kastler Brossel) visits us today at ICFO, where he gives a nice talk on his PhD thesis work. We have several interesting discussions with him, on topics as diverse as circular Rydberg atoms and the best indium seals. Thanks a lot for the visit, Tigrane!


Luis Santos (University of Hannover) visits us for three days at ICFO, during which we learn a lot about droplets and rotons in dipolar BECs.


Giacomo Roati (LENS) visits us at ICFO and gives a great talk on Josephson oscillations, phase slips and ferromagnetic domains in strongly interacting Fermi gases. Thanks a lot for the visit, Giacomo!


Julio is this week in Trieste, where he attends a cool conference on two-dimensional quantum gases and gives a talk on our latest droplet results.


Our second experimental paper “Bright soliton to quantum droplet transition in a mixture of Bose-Einstein condensates” is finally in the arXiv! Check here if you want to understand the difference between composite bright solitons and quantum liquid droplets, and learn about analogies between droplets and high order optical solitons in non-linear media.


Today is Philip’s last day in the QGE. Thanks a lot for all the contributions to the experiment that you did during your Master thesis! We wish you all the best for the future!


Leticia is this week in Glasgow, attending the kick-off meeting of the DesOEQ project. There, she gives and invited talk on our latest droplet results. It is a very good occasion to learn more about the cool quantum gas research that is going on at Strathclyde, Cambridge and Oxford.


Alberto finishes today his summer internship in the group, during which he developed a setup for optical manipulation of our droplets using a digital micro-mirror device. It was great having you in the QGE, Alberto! All the best for the future!


Leticia is this week in Gdansk attending the Quantum Optics IX conference. There, she gives an invited talk on our recent and ongoing quantum droplet experiments. This is a very nice conference full of interesting presentations, posters and discussions. Thanks a lot to the organizers for the invitation!


Thomas Bourdel (Institut d’Optique, Palaiseau) and Daniel Greif (Harvard University) visit us after the BEC conference. It is great to have them at ICFO and show them our potassium lab. In the afternoon, Daniel gives a talk where he presents their amazing single-site resolved studies of fermionic antiferromagnets. Thanks a lot to both of you for coming!




Leticia is this week in the BEC 2017 conference in Sant Feliu de Guixols, where she gives an invited talk on our recent liquid droplet results. As usual, the conference is really really inspiring (but also a bit exhausting), with so many nice talks, posters and discussions.




Breaking news! Our first experimental paper, “Quantum liquid droplets in a mixture of Bose-Einstein condensates”, is finally on the arXiv! Check here if you want to learn more about ultradilute quantum liquids stabilized by quantum fluctuations in a system with only contact interactions!

In the evening, we have a farewell dinner with Luca, who leaves us today to start a new postdoc position at LENS/INO-CNR in Florence and Pisa. There, he will work on the new dysprosium lab. We really enjoyed a lot working with you during the last three years in the QGE, Luca, and will really miss you here! Of course, we wish you all the best for your new life in Florence and hope that you will be visiting us often in Barcelona!


Group barbecue in Bruno’s terrace. Cool!


Celebrating Luca’s birthday in the new open-air space of ICFO’s cafeteria. Thanks a lot for the cake, Luca, and happy birthday again!


Igor Ferrier-Barbut (University of Stuttgart) visits us at ICFO for a couple of days and gives a great talk on their latest dysprosium droplet results. We have nice discussions on dipolar vs. mixture droplets, and get a much clearer understanding of the microscopic details of dysprosium droplets. It is really interesting to realize that, despite the very different interactions at play, both systems share so many features. Thanks for the visit, Igor!


Julio is this week in the YAO (Young Atom Opticians) 2017 conference, which this year takes place in Paris. There, he gives a talk on… quantum liquid droplets! It is great to meet and discuss with people from all groups in Europe, and learn so many things. Thanks to the local organizers -including Manel- for putting together such a nice conference.


César attends the annual ICE (Quantum Information and Quantum Technologies Spanish Network) meeting in Madrid and gives an invited droplet talk in the quantum simulation session. It is a nice occasion to meet other experimentalists in Spain, such as the quantum communications group in Madrid or the ion trappers of Granada. Thanks a lot to the Madrid QUINFOG group for the organization! We are already looking forward to the next meeting!


Jean-François Clément (Université de Lille) visits us for a couple of days and gives a talk on their kicked rotor experiments. We also have quite some discussions and explain him our 39K-41K cooling strategy. Good luck with your potassium machine in Lille!


Alberto Muñoz de las Heras joins the group as internship student, within the frame of ICFO’s summer fellows program. During the next three months he will work on the generation of dynamical potentials with a digital micromirror device, and develop a test setup for correcting the aberrations introduced by the DMD. Welcome to the QGE, Alberto!


Leticia visits the group of T. Pfau at the University of Stuttgart, and gives a talk on our ongoing droplet experiments. It is really interesting to discuss with the Dy team the analogies and differences between dipolar and mixture droplets, and to learn about their fantastic results.


Leticia is this week in Florence, attending in beautiful Arcetri the conference “Quantum science approaches to strongly correlated systems : from ultracold atoms to high-energy and condensed matter physics”, where she gives an invited talk on our latest results on quantum droplets.


“Measuring Chern numbers in Hofstadter strips”, a joint proposal with our theory friends from ICFO’s third floor, is now on the arXiv!  Check here if you want to learn about Laughlin pump experiments with synthetic dimensions, and an intuitive way of understanding the Chern number.


Luca and Leticia spend two days in Florence, attending the first meeting of the QUIC – Quantum insulators and conductors project, where Leticia presents an update of our ongoing droplet experiments. It is great to discuss with all the participants of the meeting and visit the ultracool ultracold LENS labs. We have particularly interesting exchanges with the potassium team on droplets, with Matteo Zaccanti on Efimov physics, and with the lithium lab on imaging. And, of course, it is a lot of fun to meet the Zurich and Florence friends again!


Celebrating Leticia’s birthday in ICFO’s cafeteria. Thanks a lot for the cake!


Bruno Naylor joins the group as a postdoc. Welcome, Bruno!


Farewell lunch with Pierrick, who finishes this week his postdoc in the QGE. Thanks a lot for all your contributions to the experiment! We wish you all the best for your new research on inertial navigation with cold atoms!


Group travel to Munich, to attend the kick-off meeting of the research group on artificial gauge fields and interacting topological phases on which we participate as associated member. There, Pierrick gives a talk on our latest experiments, and César, Julio, Luca and Philipp present a poster. Unfortunately, Leticia stays in Barcelona with a bad knee and cannot attend the cool talks, discussions and labtours.


The complete group takes part in the 5th half-day meeting on cold atoms in the Barcelona region, which is this year organized by Bruno Juliá Díaz at the University of Barcelona. Luca gives a talk on our soliton and droplet measurements, and Julio presents a poster with all the experimental details. As always, it is great to learn on the progress of the different teams and discuss with Fabrice Gerbier (LKB), who is this year’s invited speaker.


Pierrick visits LP2N at Institut d’Optique in Bordeaux, where he gives a talk on our recent liquid droplet experiments.


Alessio Recati (Munich/Trento) visits us this week, and gives a talk on “Coherently coupled Bose gases”. We have many interesting discussions with him on RF coupled Bose gases, polarons and quantum simulations of gravity.


“Many-body interferometry of magnetic polaron dynamics”, our theory proposal in collaboration with Y. Ashida, R. Schmidt and E. Demler, is now in the arXiv.


“Synthetic Unruh effect in cold atoms”, our theory preprint in collaboration with J. Rodríguez-Laguna, M. Lewenstein and A. Celi, is accepted for publication in Phys. Rev A.


“Proximity effects in cold atom artificial graphene”, our theory preprint in collaboration with T. Grass, R. Chhajlany, V. Pellegrini and M. Lewenstein, is accepted for publication in 2D materials. Cool!


Bruno Naylor (Université Paris Nord) visits us for a couple of days and presents some of the experiments done during his PhD thesis, on the study of spin physics with chromium atoms.


Philip and Luca do the first tests of our new green laser. It is really quite a bit of power…


Julio and Pierrick assemble today our new 2D MOT chamber in lab 003.


Our new 532 nm laser, which we will use for preparing low-dimensional quantum gases, arrives today!


Julio succesfully defends today his Thesis Proposal in front of a committee formed by Thierry Lahaye (Institut d’Optique), Hugues de Riedmatten and Rob Sewell (ICFO). Well done, Julio!
We take advantage of Thierry’s visit for learning more about their bottom-up approach to quantum simulation using Rydberg atoms.


Philip Thomas joins the group for his Master thesis within his physics studies at the University of Hamburg, and will work during the coming year on the design and construction of an optical lattice setup for our potassium experiment. Welcome to the QGE group, Philip!


Iñigo finishes today his summer internship in our group, during which he worked on generating arbitrary potentials for our experiment using a digital micro-mirror device. It was great having you with us during the last three months. We wish you good luck for the future!


Pierrick is this week in Newcastle attending the MACRO mini-conference, where he gives a talk on our measurements of the soliton-to-droplet crossover in attractive Bose-Bose mixtures.


Julio is this week in Bonn, attending the Greenhorn meeting 2016 where he gives his very first scientific talk! For this occasion, he presents our experiments on interactions, solitons and droplets in potassium Bose-Bose mixtures.


Luca is these days in beautiful Salerno, attending the BEC2016 conference. He also presents a poster on our latest results on the soliton-to-droplet crossover in attractive Bose-Bose mixtures.


Vincent finishes today his Master 1 internship project, during which he set up a magnetometer exploiting Faraday rotation in a cell of potassium atoms. We hope you enjoyed your stay here as much as we did, and wish you all the best for the next steps!


Pierrick is this week in Seoul, attending ICAP 2016. Besides listening to fantastic talks, he also presents a poster on our initial results on the beyond-mean-field stabilization in attractive Bose-Bose mixtures.


Eugene Demler (Harvard) visits us today, and gives a talk at ICFO on Bose and Fermi polarons. Discussing with Eugene is as always very inspiring.


Iñigo Urtiaga joins the group as ICFO summer fellow, and will work on the generation of flexible trapping potentials for our BECs using a digital micro-mirror device. Welcome to the group, Iñigo!


Today we get the first phase contrast images of 41K and 39K BECs taken with the new objective!


Pierrick is this week in Paris, where he presents our work in the workshop Dynamics and Transport in Quantum Gases at the University of Cergy-Pontoise.


QGE in El País! And it’s a great group picture, isn’t it?


First trials of dual gray molasses on the D1 transition, cooling simultaneously 41K and 39K.


First in situ images with the new objective. It works!


We install today our homemade objective on the machine. Thanks to Julio’s extensive preparation work, everything goes very smoothly. Next step: imaging!


Today is the Spanish Royal Physical Society Award Ceremony, where Leticia receives the young experimental physics prize. One of the nicest things in the evening is certainly to meet again several of the first year UCM physics professors.


César is this week in Bad Honnef, participating in the Quo Vadis BEC conference. Besides attending all the nice talks, he also presents our work on dual BECs and Feshbach spectroscopy in his poster.


Luca is this week in Palma de Mallorca, where he presents our work on dual 41K and 39K BECs in the annual ICE conference (meeting of the quantum tecnologies and quantum information network in Spain).


Celebrating Vincent’s arrival in the group’s favourite japanese restaurant.


Vincent Brunaud joins the group to do his third year internhip from Ecole Polytechnique, and will develop a magnetometer using potassium atoms. Welcome to the group, Vincent!


Pierrick and Cesar give an inventor crash course to other ICFOnians within the ICFO+ program.


Pierrick is today in Toulouse, where he gives a talk presenting our experimental apparatus and future plans.


We (finally!) see Rabi oscillations between different Zeeman sublevels of potassium.


We organize at ICFO the half day meeting on cold atoms in the Barcelona region 2016. Our annual meeting is a great occasion to keep up with the research lines of the quantum gases groups at UB, UAB, UPC and ICFO. This year César gives a talk and Julio presents a poster on our latest experimental results.



Observing a new s-wave Feshbach resonance in the 39K-41K mixture.


Today we observe for the first time the miscible-immiscible transition in a 39K-41K mixture! Also, Leticia is awarded the young experimental physics prize of the Spanish Physical Society.

Celebration phase separation


Celebrating the new 39K BEC, the fat 41K one (ultra-pure with 250000 atoms) and the new 39K-41K degenerate mixture in a Greek restaurant.
Celebrating 39KBEC


Dual BEC of 39K and 41K! We produce for the first time this degenerate Bose-Bose mixture. Now, we just need to make the BECs grow…


First 39K BEC!!! Sympathetic cooling of 39K by evaporation of 41K to quantum degeneracy works! Not too bad to start 2016.


QGE group season’s greetings: Feliz Navidad y Próspero 2016!
During 2015 we worked on cooling down all potassium isotopes: 41K (BEC Christmas tree), 39K and 40K (red MOT balls and white snow MOT balls respectively).


QGE Christmas dinner 2015.
ChristmasDinner2016Group picture christmas 2015


Our brand new dipole trap works, and we get nice 41K BECs in it.


César and Pierrick present our research to all ICFOnians with a poster and a talk during the ICFO day, and César is awarded the poster prize. Congratulations!


39K in |1,1> in the crossed dipole trap.


Today we get for the first time sympathetic cooling of 39K atoms by radio-frequency evaporation of 41K in the magnetic trap, and load up to 2×106 39K and 4×106 41K atoms in the crossed dipole trap!


First 39K atoms in the magnetic trap.


First two-isotope MOT! Cooling and trapping simultaneously 39K and 41K works!


Julio starts officially today his PhD training period in the group. Welcome back, Julio!


Jordi successfully defends today his bachelor thesis (TFG for the UPC degrees of Physics and Telecomunication engineering) entitled “Design and construction of optical superlattices for a quantum gas experiment”, and is awarded an excellent 9.8/10 grade. Well done, Jordi! It was a pleasure working with you during the last year, and we wish you all the best for your Master in Zurich!
Afterwards, we go to Bill Phillips’ general public talk “Time, Einstein, and the coolest stuff in the universe…” in La Pedrera. We were already convinced that ultracold is ultracool and ultrafun, but after two hours of playing with balloons, magnets, liquid nitrogen and even an explosion, hopefully the complete audience agrees with us.


Our BEC is back! After six bad weeks, during which we had to replace a leaky vacuum viewport in the 2D MOT chamber, we recover a nice BEC of more than 100000 41K atoms.


ICFO organizes a symposium to celebrate the birthdays of Roy Glauber and Maciej Lewenstein. We enjoy a lot the two days of great talks and meet many friends and colleagues. It is particularly fun to show the lab to Tilman Esslinger and see again most of the former members of the QOT group.



Leticia writes together with Alessio Celi a Perspective article in Science commenting on the recent NIST and LENS experiments which visualize edge currents using synthetic gauge fields in synthetic dimensions.


Cesar defends successfully today his thesis proposal in front of a committee formed by Selim Jochim (University of Heidelberg), Maciej Lewenstein and Robert Sewell (ICFO). We have very inspiring discussions with Selim on his bottom-up approach to quantum magnetism, and some fun showing him the lab.


Julio spends two weeks in Les Houches, attending the Cold Atoms PreDoc School “Exploring new quantum gases”. He presents a poster, and Leticia gives a series of lectures during the second week on Fermi gases in optical lattices. Great training to start a PhD thesis in the best conditions!


Julio defends successfully today his master thesis entitled “Design and construction of a fluorescence imaging system for a quantum gas experiment” and is awarded the best possible grade (Matrícula de Honor). Well done, Julio!



Pierrick and Leticia attend this week the BEC 2015 – Frontiers in Quantum Gases conference in Sant Feliu de Guixols. This year, besides all the inspiring talks and discussions, there is also a special celebration for the 20 years of the first observation of BEC.


Luca and Leticia attend this week a cool workshop in Dresden on Synthetic Quantum Magnetism. Luca presents a poster describing our experimental apparatus and future plans, and Leticia gives a talk on the Zurich spin correlation experiments.


Leticia is this week in Glasgow, where she gives a series of lectures at the 71st Scottish Universities Summer School in Physics. It is a great opportunity to visit the fermionic quantum microscope lab of Stefan Kuhr, learn about the physics that is going on in Andrew Daley’s group and discover the atomic interferometry and super cool miniature MOTs that are developed at Strathclyde.


Jordi appears today in La Vanguardia, in a focus article on the UPC Physics Engineering studies, and explains in a few words what BEC is for the general public.


The crossed dipole trap finally works nicely.



Cesar gets today the pneumatically actuated mirror mounts for the MOT installed and working well.


Leticia is in Les Houches, where she gives a seminar in the Statistical Physics Predoctoral School.


Conference week: Pierrick is in Trento, attending the Cold Atoms Meet High Energy Physics workshop, whereas Leticia is in Warsaw, where she gives a keynote talk at the Quantum Technologies VI conference.


Heading to fermions: today we see our first 40K MOT!
First_MOT 40K


Group dinner in a Japanese restaurant to celebrate our first BEC and, as one can see from Julio’s T-shirt, the Barça victory in the Champions League.


We have a BEC!!!
The first Spanish condensate was born today at 20h20. When pure, it has about 15000 41K atoms at 20 nK. Ultracold is ultracool!


It is getting colder and colder in lab 002: we now have more that one million atoms at 1 uK in the optical dipole trap!


Today we see first atoms in the optical dipole trap.


Today we get PSD=2.5×10-5


Our first phase-space density measurement: PSD=10-6 after loading in the quadrupole trap
We do first trials of RF evaporation.


Testing vacuum: we have >4 min lifetime in the magnetic trap!!!
We also get our lowest temperature to date: 16 uK after D1 gray molasses, with > 109 atoms.



Optical pumping and first atoms in the quadrupole trap!


Leticia is today in Zaragoza, where she gives a talk in the condensed matter seminar series. It is really interesting to learn about their circuit-QED research there, both from the theoretical and the experimental point of view.


First trials of sub-Doppler cooling with gray molasses.


Our CMOT works!
Nice CMOT 25-04-2015


Today we make our first really large 41K MOTs.


Cesar is this week in Zurich attending the YAO (Young Atom Opticians) conference, where he also presents a poster on our experimental status.


The bottom Bitter coil assembly is installed on the experiment. All our magnetic field coils are mounted now, so we are ready for experiments. Also, today is Lisa’s last day in the group. It was great having you all those last months, good luck with the future!


The imaging test setup, with the complete lens tube, works. Well done, Lisa!



We successfully install the top Bitter coil assembly on the science chamber!


Many interesting talks and visits this week at ICFO thanks to the annual meeting of the SIQS FET project. Nice occasion to meet friends and learn about latest advances in the field.


Nathan Goldman and Alexandre Dauphin visit this week the QOT group. Great talks on topological systems!


We are participating in the quantum simulation FET collaborative project QUIC – QUantum Insulators and Conductors- together with groups at LENS, Institut d’Optique, ETH Zurich, University of Trento, Jagiellonian University and of course ICFO.


Tarik Yefsah (MIT) visits us in his way back from Benasque. It is fun to see him again, chat about solitons and remember the ENS times.


Jordi Sastre starts today his bachelor thesis (proyecto de fin de grado) project in the group, on the construction of our optical lattice setup. Welcome back to the QGE, Jordi!
Also, we finally observe the fluorescence of the atomic beam from the 2D MOT. Our longitudinal molasses cooling really works!


Leticia visits Henning Moritz’s group in Hamburg. It is great to see their fully built lithium machine, to discuss physics and technology, and of course to meet again old friends. Thanks also to the Sengstock group for the labtours.


Imaging smaller and smaller objects with Lisa’s test imaging setup. Current record: seeing element 9-3 of the USAF 1951 test target.
USAF test setup


Pierrick is awarded a Marie Curie fellowship. Congratulations!


ICFO ski weekend in Andorra, attended by almost all the QGE group. Awesome snow conditions and a lot of fun!

QGE group Andorra 2015


The complete group attends the annual Cold Atoms in Barcelona meeting at UAB, where all BEC-related groups in the region present their current research. Pierrick gives a talk on our experimental progress, and Cesar presents a poster. It is a great opportunity to get to know each other better, and learn about what’s going on in the other teams.


First absorption images.

First absorption image


Leticia goes to the Netherlands, to the FOM Physics meeting in Veldhoven. It is a great occasion to visit as well Florian Schreck’s super cool new labs in Amsterdam, and learn about Strontium.


First 41K 2D and 3D MOTs.


QGE group season’s greetings: Feliz Navidad y Próspero 2015!


First potassium MOTs in our apparatus: in the science chamber (star) and in the 2D MOT chamber (tail).


First MOT in the science chamber of our apparatus! We trap our first cold atoms in there just a few minutes before going to ICFO’s Christmas dinner. There we really have something to celebrate! Exciting times are waiting for us after the Christmas break. Happy holidays to everyone!!!



Today we see our first 2D and 3D MOTs, just in time for Christmas!!! By adding a pair of coils in the longitudinal direction, we make a 3D MOT of 39K in the 2D MOT chamber. Switching off these coils allows us to image a few minutes later our first 2D MOT as well. Really easy!

First3DMOTin2D MOTchamberFirst2DMOT


Leticia is awarded one of the five fellowships of the 2014 L’Oréal-UNESCO For Women In Science Spanish program. Maybe this will boost parity in our group in the long term? For the moment, it will certainly boost Lisa’s imaging project!


We also see potassium fluorescence in the 2D MOT chamber today. Hunting for a 2D MOT in progress…


Leticia is in Madrid today, in Emilio Alba’s PhD defense at UCM. Congratulations, Dr. Alba!


Leticia is in Bordeaux for a couple of days, in a workshop on Dirac and Topological Matter organized by Jérôme Cayssol. A very nice occasion to present our ETH experiments, learn more on the topic from a solid-state perspective, meet again the Bordeaux colleagues and see the progress of LP2N.


Seeing potassium absorption in the 2D MOT chamber. Yes, there is really potassium in there.


Group dinner in Leticia’s place. We have to celebrate that we are really a potassium team now.



Today we break the potassium ampoule inside the 2D MOT chamber!


Luca Tanzi joins the group as a postdoc. Welcome to the group, Luca!

Also, we obtain funding from the BBVA Foundation to develop further our imaging system. Cool!


We finish today the chamber bake-out!


Leticia is this week in Benasque, teaching in a Quantum Optics and Non-linear Optics School of the Optics Section of the Spanish Physical Society, organized by Germán de Valcárcel and Verónica Ahufinger.


Julio Sanz joins the group as a master student. Besides working on the experiment, he will do as well a theory project with Pietro Massignan on the Bose polaron, to prepare possible experiments. Welcome to the group, Julio!


Today we finish assembling the viewports of the vacuum chamber. In the pictures one can see the machine in its final configuration.
Machine before final bakingchamber of secrets


Farewell futbolin and tapas with Manel, who leaves us today after the end of his Master thesis. It was great having you in the group, and we all wish you a lot of good luck for your new Yb adventure in Paris!

Farewell futbolin ManelFarewell tapas Manel



Manel successfully defends today his master thesis “An experimental setup for gray molasses sub-Doppler cooling of potassium gases”, being awarded the best possible grade (Matrícula de Honor). Well done, Manel!


Salvatore Manmana (University of Goettingen) visits us today in his way back from Benasque and presents some of his latests results on the dynamics of strongly correlated 1D fermionic systems.


Lisa Saemisch joins us for a six-month internship within her Master studies at the University of Bonn. During this time she will work on the design and construction of our imaging system. Welcome to the group, Lisa!


The chamber is finally back to room temperature. Measured pressure: 5×10-10 mbar, limited by the detectivity of our hot cathode gauge.


Chamber during the high temperature bake-out. What animal do you see in there?


Congratulations to César for being awarded a CONACYT PhD fellowship from Mexico!


We start baking the main vacuum chamber. Also, today is Vincent’s last day at ICFO. All the best for the future!
High temperature bakingVincent's last day


Farewell evening for Vincent, who finishes tomorrow his internship in the group. In his honor we organize the first QGE pétanque game in front of ICFO. For sure it will not be the last one…

Petanque jugglingFirst QGE petanque


After all the baking we get nice vaccum in our 2D MOT chamber.

2D MOT pressure


Tasting horchata with fartons at ICFO’s cafeteria. Thanks a lot, Jordi!


Pierrick builds today the first complete Bitter coil assembly and test both the Feshbach and quadrupole coils with up to 400 A.


We have finished the assembly of our vacuum system (except for the viewports), which is now ready for the high temperature bakeout.


Our 2D MOT chamber is finally ready (no leaks) and we start baking it.
2D MOT_zoom



César is this week in Varenna (Italy), attending an ultracool summer school on Quantum Matter at Ultralow Temperatures.


We start assembling the vacuum chamber today.


Jordi Sastre (physics and telecomunication engineer student from UPC) joins the group as ICFO Summer Fellow. During the next three months, he will work on the setup of our RF and MW system, as well as on the computer control of the experiment. Welcome to the group, Jordi!


Houches Summer School


Leticia is this week in Les Houches (France) where she gives a presentation in the computational physics summer school that Tommaso Roscilde and Markus Holzmann are organizing this summer. It is a great occasion to learn more about numeric methods for strongly correlated systems and meet again former collaborators, as both Corinna Kollath and Lode Pollet are teaching the same week.


Leticia is in Aarhus (Denmark), attending the conference Cold atoms and beyond organized by Jesper Levinsen and Georg Bruun, and gives a talk on the ETH magnetism experiments. This is a very nice and lively conference, and although it is hard to get there due to airport strikes, it is really worth it!


Assembling the 2D MOT chamber. Our first indium seals turn out to leak, we need to work a bit more on that…


Tobias Tiecke (Harvard University) visits ICFO and gives a very cool talk on merging nanophotonics and cold atoms. It is nice to see Tobias again, discuss a bit about physics and show him our lab.


Golden mirror


Today we make use of the ICFO clean room facilities to coat with gold the in vacuum mirror for our 2D MOT. Thanks a lot to the NPL people for the great job!



Winding the first 2D MOT coil!
2D MOT coil

Manel with first vacuum


Our first Spanish vacuum! We start slowly, just baking the kapton insulated wire for our RF antennae to check how well our brand new ultrasound bath, pumping stations, gauge, variacs, heating tapes and temperature logger work.


Alessandro Seri (University of Camerino) visits us and gives an informal presentation on his Master thesis work, on “Two-qubit entanglement by a commercial projector”.


We get today a second lab for the group! It is great to have more space to test electronics, coils and optics, and also to bake our vacuum chamber.
Moving the optical tableTiding up the lab 003The lattice boys in lab 003


Oleksiy Onishchenko (TU Delft) visits us and gives an informal presentation on his Master thesis work in Ronald Hanson group.

Mephisto MOPA arrival


Our YAG laser for the dipole trap arrives today at ICFO!


Luis Santos (University of Hanover) visits ICFO for two weeks. We have a very interesting discussion on interaction modulated optical lattices, and also enjoy a lot his talk.


Luca Tanzi (LENS) visits us for two days, and gives a talk on his PhD thesis work: the study of strongly correlated Bose gases in quasi-periodic potentials and the observation of a Bose glass. It is really interesting to learn from Luca about the different phases that arise from the interplay of disorder and interactions, and how to detect them. We are specially impressed by the spectroscopic features that they observe now. We hope that Luca enjoys the visit to the different ICFO cold atom labs, and the long discussions with Maciej’s group. In the evening we go for tapas and drinks in Barceloneta with Pietro and, as always, “Massignan advisor” never fails!


Leticia is awarded a Marie Curie Career Integration Grant. We of course already have many ideas of equipment that we will get for the experiment with it. In the evening we go for tapas and drinks to celebrate. There are many other things to celebrate as well: the big progress in the laser system and the tapered amplifiers, the coils, Vincent’s arrival… Christine Guerlin (LKB) is visiting for the weekend, and she comes to celebrate with us.


Georg Brunn (University of Aarhus) visits Pietro Massignan at ICFO today and gives a great talk on the Higgs mode in microtrapped fermionic systems and on quantum hexatic phases. We have a nice discussion with Georg over lunch time.


Vincent Lienhard joins the group for his ENS Cachan M1 internship, during which he will develop EOMs, a part of the laser system and start preparing our optical dipole trap. Welcome to the group, Vincent!


OIST photo small

Leticia is this week in a workshop organized by OIST at Okinawa (Japan), where she gives an invited talk on fermions in tunable geometry optical lattices. In the poster session we have interesting discussions on unitary Bose-Fermi mixtures and on Bose-Bose mixtures in optical lattices. It is nice to meet former collaborators again: Jing Zhang and Corinna Kollath are also attending the conference.


Celebrating Leticia’s birthday at ICFO’s cafeteria (one day in advance). Thanks very much to César, Manel and Pierrick for the cake!

Leticia's birthday


Manel gets his laser locked on the D1 line today. Our four lasers are locked now!


Lisa Saemisch (University of Bonn) visits ICFO. Lisa will join the group next fall for a 6-month internship, during which she will work on the development of our imaging system.


ICFO hosts this week YAO, the Young Atom Opticians conference. It is a great opportunity to see what’s going on in most of the European groups in the field. It is also nice to see the newest results of the ETH lattice machine, and the progress of the Bordeaux experiment. Leticia gives a talk, and César presents a poster which is the most voted in the poster competition. Well done, César!

YAO2014 group pictureYAO 2014 lab002 visit


Our pizza dinner pays off: Pierrick gets today the first Bitter coil prototype working!


César gets the two offset locks for the cooling and repumping lasers working. All lasers on the D2 transition are stabilized today. In the process, we order our first pizza dinner at ICFO to get some energy and finish the work.
First pizza in the lab Bitter coil prototype


Sebastian Diehl (University of Innsbruck) visits ICFO and gives a series of lectures on the Keldysh formalism for dissipative quantum systems.


Francesca Ferlaino (Univeristy of Innsbruck) visits ICFO. As always, it is very nice to see Francesca and chat about life, physics and Erbium with her.


Alexandre Dauphin (UCM and ULB) visits ICFO this week and gives a talk on the detection of topological order in cold atom systems. It is nice to see Alexandre again and discuss about possible implementations of his proposals on our new setup.


First K spectroscopyToday we see our first potassium spectroscopy in the lab!  Also, our ETH theory-experiment comparison for the magnetism experiments is accepted in PRL.


Sören Dörscher (University of Hamburg) visits us and gives a talk on his PhD thesis work: the construction of an Yb BEC and DFG apparatus. We learn a lot on AEL atoms, and also on the physics that is going on in Klaus Sengstock’s group. In the evening we go for dinner in Gotic, do a bit of wine tasting and even have a look at the Barceloneta beach by night.


Our lab is officially delivered today, the building works being completely finished. We have been getting a nice temperature stability over the last days: about 0.1ºC inside the enclosures of the optical tables. Let’s hope it stays like this forever. Of course, this would not have been possible without the efforts of the ICFO facilities’ team. Thanks a lot for all those months of hard work!

first screwStarting the laser systemLab002


Leticia goes to Madrid to attend the 6th Madrid meeting on ultracold atoms, and gives a talk on tunable geometry lattices. Now we know not only the cold atom physics that is going on in Barcelona, but also in Madrid. Thanks to Francesca and Belén for the invitation and the great organization!


Grigori Astrakharchik organizes at UPC a half-day meeting on cold atoms in the Barcelona region. It is a good occasion to present our work and learn about the physics that our neighbors do not only at ICFO, but also at UAB, UB and UPC.


We take our first group picture. The weather is quite nice, so we go to the beach of Castelldefels for it. According to Pierrick, next time we should bring not only the camera, but also a good photographer. In the afternoon, Pierrick winds our first coil! Many of them will follow…
Group picture 29-01-2014first cloverleaf coil


César starts officially his PhD training period in our group.


Carlos Lobo (University of Southampton) visits ICFO and gives a very interesting talk on optical lattices with large scattering length.


César Cabrera arrives to Barcelona, and will start soon his PhD thesis in the group. Welcome to Spain, César!


Pau Gómez (LMU Munich) visits us. In the picture, Pau, Pierrick and Leticia eating german Christstollen and cookies in the cafeteria. Thanks, Pau!
Christstollen and cookies at ICFO


Manel Bosch joins the group as a master student, and will work on the design and construction of a laser system on the D1 line for gray molasses sub-Doppler cooling. Welcome, Manel!


Invited by Grigori Astrakharchik, Leticia gives a talk at UPC entitled “Engineering synthetic quantum materials with ultracold fermions in a tunable-geometry optical lattice” on the ETH Zurich experiments. Afterwards we brainstorm a bit on possible experiments with isotopic potassium mixtures, as well as on experiments with strongly interacting fermions in shallow optical lattices.


Pierrick Cheiney joins the group as a postdoc. Welcome, Pierrick!


The optical tables are installed in the lab!

The optical tables are now in the labOptical table and closets in the lab


The major part of our lab renovation is finished! Now that ICFO’s lab 002 is almost ready, we can start to move in.


Cesar Cabrera (University of Bonn) visits ICFO and gives a presentation on his Master thesis work in Martin Weitz’s group, where he worked on the generation of optical lattices for photon BECs.


The comparison of our ETH magnetic correlations experiments in effective 1D chains to theory is now on the arxiv. The DCA simulations done in Matthias Troyer’s group show that our measurements correspond to temperatures below the tunneling in the chains. Our method is thus well adapted to the study of low temperature 1D physics.


Our optical tables arrive this morning to ICFO!


Invited by Miguel Angel Martín Delgado, Leticia visits Universidad Complutense de Madrid and gives a talk entitled “Engineering synthetic quantum materials with ultracold fermions in a tunable-geometry optical lattice” on the ETH Zurich experiments. At UCM we have interesting discussions on the influence of dissipation on topological phases. We also talk about detection schemes for edge states, as well as about digital quantum simulation schemes with ions and Rydberg atoms. Going to Madrid is a nice occasion to visit Juanjo García Ripoll and Jordi Mur at CSIC too.


The week is very busy, with so many participants from the BEC 2013 conference visiting ICFO and presenting (formally or informally) their work: Tarik Berrada (Vienna), Manuele Landini (Florence), Jesper Levinsen (Aarhus), Ludwig Mathey (Hamburg) and Meera Parish (London). Good friends from Zurich times visit Barcelona as well: Kris Baumann (Stanford), Daniel Greif and Renate Landig (ETH Zurich) are here!


Leticia goes to Sant Feliu de Guixols for the BEC 2013 conference, and presents a poster entitled “Short-range quantum magnetism of ultracold fermions in an optical lattice” on the ETH Zurich work. The hot topic of the conference this year is without any doubt the simulation of artificial gauge fields, and Wolfgang Ketterle presents a very clear introduction to the topic. The Rice results (and our experiments) on magnetism are actively discussed as well. It is great to have so many inspiring discussions, and also to meet again so many good colleagues and friends! We take advantage of the occasion to plan with Tobias Donner, Thomas Uehlinger and  Henning Moritz the future developments of Experiment Wizard, with which they do the computer control of the experiments in Zurich and Hamburg, and that we will use in Barcelona. We also discuss with Corinna Kollath, Lei Wang and Matthias Troyer the status of the numerical simulations that they have done for our ETH spin work.


Henning Moritz (University of Hamburg) visits ICFO in his way to the Sant Feliu BEC 2013 conference. We have endless discussions on basically everything, from air conditioning systems to ion trapping and the physics of 2D Fermi gases. Henning is happy to see the progress of the labworks after all the advice he gave (thanks again!). In the evening we go out for dinner and drinks in Barcelona with Jing and Henning. As Pietro Massignan (ICFO) and Matteo Zaccanti (LENS) join, Fermi polarons are part of our beers’ discussions.


Jing-Zhang-web Jing Zhang (University of Shanxi, China) visits ICFO to give a talk entitled “Experimental study of a spin-orbit coupled degenerate Fermi gas”. It is really nice to see Jing again after all those years and remember the old ENS times. We have many interesting discussions, from non-abelian gauge fields to magnetic field control and optimal coil windings.


Sebastian Krinner (ETH Zurich) visits Barcelona in his way to a satellite meeting of the BEC 2013 conference on disordered systems. It is a very nice occasion to learn about the most recent progress on the ETH transport experiment.


Pierrick Cheiney (University of Cambridge) visits ICFO to give a talk entitled “Scattering of matter-waves on a finite size lattice”, on his PhD thesis work in David Guéry-Odelin’s group at the University of Toulouse.


Laura Corman (ENS Paris) visits ICFO, and also Barcelona for the weekend. In the breaks from our touristic visits of the city we have interesting discussions on her recent experiments in Jean Dalibard’s group on 2D Bose gases in box-like potentials.


Leticia visits ETH Zurich. Besides taking part on the yearly quantum optics group hike and meeting all the QO people again, it is great to see the recent progress on the four experiments, and especially on the lattice machine! Martin Lebrat presents the status of the EOM technology transfer project as well. Tobias Donner and Tilman Esslinger give great advice and a lot of tips on lab renovation and organization. Thanks a lot, Tobi and Tilman!



Martin Pototschnig (Caltech) visits ICFO to give a talk on “Interfacing Cold Atoms”. Martin presents the progress done in Jeff Kimble’s group on coupling cold atoms to photonic crystal structures. It is a nice occasion to get to know better the work of Darrick Chang’s group at ICFO on the theoretical proposals for these experiments.


During the whole week ICFO hosts a summer school on “Frontiers of Quantum Physics and Quantum Information”. Particularly inspiring for our research are the lectures of Ignacio Cirac on Tensor Network Methods, Misha Lukin on CQED with nanophotonic systems and Immanuel Bloch on optical lattices, where he presents the Munich realization of the Harper hamiltonian.


The QGE group (Quantum Gases Experimental group) website is launched. Thanks a lot to ICFO’s IT unit for their support, and to Romain Pacanowski (Institut d’Optique, Bordeaux) and Thomas Uehlinger (ETH Zurich) for their very good advice!


Invited by Salvatore Manmana, Leticia visits Götttingen and gives a talk on “Simulating synthetic quantum materials with ultracold fermions in a tunable-geometry optical lattice”. Götttingen is an awesome university city, and it is quite impressive to see the original Hilbert-Raum (not so large after all…), Heisenberg’s office window and the old physics department where quantum mechanics was born. We have interesting discussions on out-of-equilibrium physics, solar cells and multi-orbital lattice models.


After a lot of planning, our lab renovation works start! ICFO’s lab 002 will be completely remodeled to meet our needs. This includes the installation of a new air conditioning system, temperature stabilized flow boxes and a water cooling circuit. The electricity of the room will be modified as well, to have enough power for our Feshbach coils.


Leticia goes to CLEO 2013 (San José, USA), and gives an invited presentation on the Quantum Simulators Symposium entitled “Simulating graphene with ultracold fermions in a honeycomb optical lattice”, on the ETH Zurich work. Going to the Bay area is a very nice opportunity to visit the Stanford labs as well, including Mark Kasevich’s and Ben Lev’s experiments. In particular, it is great to see Kris Baumann again, and learn about his work on the Dysprosium machine! In San Francisco, Jason McKeever shows the Entanglement Technologies lab, and their gas sensing prototype using two high-finesse optical cavities. It is exciting to see all this lab technology finally getting industrial applications.


Leticia moves to Barcelona. The Ultracold Quantum Gases Group at ICFO is born!