FYI -------- Weitergeleitete Nachricht -------- Betreff: REMINDER Q-mat Colloquium by Florian Schreck at LUH, 10. April 2025, 4 pm Datum: Wed, 9 Apr 2025 09:24:23 +0200 Von: Anke Schmidt <anke.schmidt@DQ-MAT.UNI-HANNOVER.DE> Antwort an: Anke Schmidt <anke.schmidt@DQ-MAT.UNI-HANNOVER.DE> An: MEMBERS-DQMAT@LISTSERV.UNI-HANNOVER.DE Dear DQ-mat members and interested scientists, We are are pleased to announce the next colloquium which will take place on *_Thursday, 10. April 2025_*_ __LUH__, Building 1101, Room D326, Welfengarten 1, 30167 Hannover _ _Schedule for this day:_ * 10-12: DQ-mat wide TG Meeting on "Designed quantum states for matter wave interferometry" with talks (20+5 min) by the following projects: o A05: Rui Li o B01: Martin Quensen o B07: Vishu Gupta o B09: Ali Lezeik * 12-13: Lunch in mensa * 13-15.30: Lab tours - please sign up here: https://seafile.projekt.uni-hannover.de/f/0dc2c96b5dbe4d0b9057/ * 15:30-16: Get-together with coffee and cake * 16-17: Colloquium by Florian Schreck * 17-18: PI Meeting and more discussions, coffee and cake (if there is anything left) *_16:00-17:30_*Colloquium by *Florian Schreck - *University of Amsterdam, Netherlands Title: *ContinuousBose-Einstein condensation and superradiant clocks* Abstract: Ultracold quantum gases are excellent platforms for quantum simulation and sensing. So far these gases have been produced using time-sequential cooling stages and after creation they unfortunately decay through unavoidable loss processes. This limits what can be done with them. For example it becomes impossible to extract a continuous-wave atom laser, which has promising applications for precision measurement through atom interferometry [1]. I will present how we achieve continuous Bose-Einstein condensation and create condensates (BECs) that persist in a steady-state for as long as we desire. Atom loss is compensated by feeding fresh atoms from a continuously replenished thermal source into the BEC by Bose-stimulated gain [2]. We are now using our new techniques also to tackle another challenge: the creation of continuously operating optical atomic clocks, which promise higher measurement bandwidth and better short term stability than traditional optical clocks that operate in a pulsed manner [3,4,5,6]. I will present our progress in building superradiant and zero-deadtime clocks. *References* 1. N. P. Robins, P. A. Altin, J. E. Debs, and J. D. Close,/Atom lasers: Production, properties and prospects for precision inertial measurement//,/ Physics Reports529, 265(2013) <https://www.sciencedirect.com/science/article/abs/pii/S037015731300118X>. 2. C.-C. Chen, R. González Escudero, J. Minář, B. Pasquiou, S. Bennetts, and F. Schreck, /Continuous Bose-Einstein condensation,/Nature <https://www.nature.com/articles/s41586-022-04731-z>*606*, 683 (2022) <https://www.nature.com/articles/s41586-022-04731-z>. 3. M. A. Norcia, M. N. Winchester, J. R. K. Cline, and J. K. Thompson, /Superradiance on the millihertz linewidth strontium clock transition/, Sci. Adv. 2, e1601231 (2016) <https://www.science.org/doi/10.1126/sciadv.1601231>. 4. J. Chen, /Active Optical Clock/, Chinese Science Bulletin 54, 348 (2009) <https://doi.org/10.1007/s11434-009-0073-y>. 5. D. Meiser, J. Ye, D. R. Carlson, M. J. Holland, /Prospects for a Millihertz-Linewidth Laser/, PRL 102, 163601 (2009) <https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.102.163601>. 6. M. Schioppo et al., /Ultrastable optical clock with two cold-atom ensembles/, Nature Photonics 11, 48 (2017) <https://www.nature.com/articles/nphoton.2016.231>. Access data for the transfer: Zoom Access:**_https://us04web.zoom.us/j/932734874 <https://us04web.zoom.us/j/932734874> _ This talk is part of the "Virtual Seminar on Precision Physics and Fundamental Symmetries" series and of the SFB DQ-mat colloquium series:https://indico.cern.ch/category/12183/__ Best regard, Anke Schmidt -- Leibniz Universität Hannover DQ-Mat-Office, Room 308 Callinstraße 36 30167 Hannover Tel: +49 511 76214887 Fax: +49 511 76217243 Email:anke.schmidt@dq-mat.uni-hannover.de https://www.dq-mat.uni-hannover.de/ https://www.quest-lfs.uni-hannover.de/ https://www.hitec.uni-hannover.de/ https://www.quantumfrontiers.uni-hannover.de/ https://www.qvls.de