The 2nd Cold atom workshop "Atom-NO-KAI"

Date:Monday, September 28-Tuesday, September 29, 2020
Place: online(Japanese)
Speakers: Dr. Takafumi Tomita(Institute for Molecular Science, invited), Dr. Ryusuke Hamazaki (Riken, invited). About 10 oral slots and 20 poster slots will be available for participants.
Registrationhttps://forms.gle/ikaDtPhDZYyLiums8
Abstract: In order to make a leap forward in domestic cold atom research, we will hold cold atom workshop "Atom-NO-KAI" this year as well. The workshop will be held online, from September 28th (Mon) to 29th (Tue). We will invite Dr. Takafumi Tomita (Institute for Molecular Science) and Dr. Ryusuke Hamazaki (Riken). At this workshop, we also pay great attention to student presentations. We encourage students to present their research, even if their final results were not obtained yet. If you would like to participate, please register for participation. We look forward to your participation.
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Endo (Tohoku Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Nakajima (Kyoto Univ.), Fukuhara (RIKEN), Fujimoto (Nagoya Univ.), Horikoshi (Osaka City University)


The 7th Atom-NO-KAI online seminar

Date:Thursday, September 17, 2020
Place: online
Speaker: Dr. Akio Kawasaki (Stanford University)
Title: Spin Squeezed 171Yb Atomic Clock beyond Standard Quantum Limit
Abstract: State-of-the-art atomic clocks have extremely high relative stability of 1×10^(-18). One of the main factors that limit their stability is the standard quantum limit due to the quantum projection noise arising at the moment of state measurements. The standard quantum limit can be overcome by generating a squeezed spin state between the ground state and the excited state for the clock transition. To demonstrate the improvement in the stability of the atomic clock with a squeezed spin state, we constructed a cavity quantum electrodynamics system with geometrically asymmetric structure, where 171Yb atoms have strong coupling with photons, capable of performing spin squeezing in spin 1/2 system of its ground state. With this apparatus, nearly-unitary spin squeezing with a metrological gain of 6.5 dB at the ground state is achieved. The squeezed spin state is subsequently transferred to the 3P0 excited state of the clock transition, maintaining its metrological gain at the ground state. This is the first realization of the squeezed spin state between the ground state and an electronic excited state. This squeezed spin state with 4.4 dB metrological gain showed a factor of 2.8 improvement in the stability of the atomic clock compared to the standard quantum limit without spin squeezing. In this talk, starting from introduction to atomic clocks, I will discuss this cavity quantum electrodynamics system and results on spin squeezing and enhancement in the stability of the atomic clock. If time allows, I will also mention precision spectroscopy of ytterbium ion for a search for new bosons, which is another project I am engaged in.
The number of participants: 63
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Endo (Tohoku Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Nakajima (Kyoto Univ.), Fukuhara (RIKEN), Fujimoto (Nagoya Univ.), Horikoshi (Osaka City University)


The 6th Atom-NO-KAI online seminar

Date:Wednesday, August 26, 2020
Place: online
Speaker: Dr. Sho Sugiura (Harvard University)
Title: Floquet-intrinsic many-body scar states in a Rydberg system
Abstract: Thermalization, which is the relaxation to a thermal equilibrium state, is a common phenomenon we encounter in our daily lives. In isolated quantum systems, it was believed that the thermalization still happen as far as the system is chaotic. However, it was recently found in the Rydberg atom system that there’re special initial states which will never relax to the thermal equilibrium, while other initial states exhibit the thermalization. Such non-thermal states are called many-body scar states. When the system is periodically modulated over time, this is called a Floquet system. Since the time-modulation excites the quantum state of the system, it was also believed that the quantum state will eventually heat up to infinite temperature in a chaotic system. In this talk, we will show that this expectation is wrong; In some chaotic Floquet systems, we have special quantum states which won’t heat up [1]. We use the PXP type interactions without disorder. We rigorously prove the existence of the many-body scar states. Experimental implementation is also proposed. [1] Sho Sugiura, Tomotaka Kuwahara, and Keiji Saito, arXiv 1911.06092 (2019)
The number of participants: 57
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Endo (Tohoku Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Nakajima (Kyoto Univ.), Fukuhara (RIKEN), Fujimoto (Nagoya Univ.), Horikoshi (Osaka City University)


The 5th Atom-NO-KAI online seminar

Date:Thursday, August 6, 2020
Place: online
Speaker: Dr. Shinsuke Haze (Ulm University)
Title: Rovibrational spectroscopy of molecular products in an ultracold atomic ensemble
Abstract: State-resolved detection of reaction products is a prerequisite building block for studying ultracold chemistry with atomic gases. In this talk, I will discuss rovibronic spectroscopy of diatomic molecules produced by three-body recombination, as a prototype chemical reaction, in an ultracold atomic ensemble. The molecules are ionized by resonantly-enhanced multiphoton ionization (REMPI) and captured within an ion trap, which results in boosting the sensitivity for detecting the molecular products. Such a combined detection method with REMPI and the ion trap technology enabled us to probe over 30 channels of reaction paths, corresponding binding energy of up to 100 GHz. I will also discuss the energy scaling of the population distribution of the product states.
The number of participants: 34
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Endo (Tohoku Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Nakajima (Kyoto Univ.), Fukuhara (RIKEN), Fujimoto (Nagoya Univ.), Horikoshi (Osaka City University)


The 4th Atom-NO-KAI online seminar

Date:Tuesday, July 28, 2020
Place: online
Speaker: Dr. Hikaru Tamura (Univ. of Michigan)
Title: Quantum science with neutral atom arrays
Abstract: Recently single atoms confined in an array of optical microtraps have emerged as a versatile platform for quantum science experiments such as quantum computing and quantum simulation. In this presentation I will talk about my past, current, and future research. I will first give a brief review of individually controlled Rydberg atoms, and introduce excitation dynamics of Rydberg atoms in various array configurations observed at UEC [1]. I will then talk about collective emission from an atom array realized at UM [2]. Particularly, we observe phase-matched enhanced emission that scales as the square of the number of atoms within an array. For two atomic arrays the emission rate is fully controlled by the array-array separation. The ability to obtain high-quality phase-matched emission from atom arrays represents an essential step toward the realization of free-space quantum links between separated arrays. In the end I will give a brief introduction of my next research. [1] H. Tamura et al., PRA, 101, 043421 (2020). [2] H. Tamura et al., “Phase-matching in lower dimensions,” (under review).
The number of participants: 51
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Endo (Tohoku Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Nakajima (Kyoto Univ.), Fukuhara (RIKEN), Fujimoto (Nagoya Univ.), Horikoshi (Osaka City University)


The 3rd Atom-NO-KAI online seminar

Date:Thursday, July 2, 2020
Place: online
Speaker: Dr. Toshihiko Shimasaki (University of California Santa Barbara)
Title: Exploration of New Phenomena in Driven Quantum Gases
Abstract: Ultracold atoms in modulated optical potentials provide new opportunities to study quantum gases away from equilibrium. In this talk, I will report several experiments performed in this direction in the Weld group at UC Santa Barbara. In particular, I will talk about Floquet prethemalization in a driven optical lattice, study of quasicrystals with a bichromatic optical lattice, and quantum simulation of ultrafast phenomena.
The number of participants: (update later)
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Endo (Tohoku Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Nakajima (Kyoto Univ.), Fukuhara (RIKEN), Fujimoto (Nagoya Univ.), Horikoshi (Osaka City University)


The 2nd Atom-NO-KAI online seminar

Date:Tuesday, June 16, 2020
Place: online
Speaker: Dr. Hideki Konishi (EPFL)
Title: Cavity QED with strongly interacting Fermi gas
Abstract: The integration of strongly correlated matter in quantum devices requires a strong, coherent coupling with photons, which still represents a formidable technical challenge. In cavity quantum electrodynamics, quantum gases such as Bose-Einstein condensates or lattice gases have been strongly coupled with light. However, neither fermionic quantum matter nor atomic systems with controlled interactions have thus far been strongly coupled with photons. We demonstrated strong coupling of a quantum degenerate, unitary Fermi gas with light in a high finesse optical cavity. In the talk I will describe our experimental setup and present the fingerprints of strong light-matter coupling. I will also discuss some consequences of strong inter-atomic interactions on the optical spectrum.
The number of participants: 68
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Endo (Tohoku Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Nakajima (Kyoto Univ.), Fukuhara (RIKEN), Fujimoto (Nagoya Univ.), Horikoshi (Osaka City University)


The 1st Atom-NO-KAI online seminar

Date:Friday, June 5, 2020
Place: online
Speaker: Dr. Shuta Nakajima(Kyoto University)
Title: Quantum state control for ultracold atoms in an optical lattice
Abstract: Due to its high controllability, ultracold atoms in the optical lattice is attracting attention as a stage for pioneering a novel quantum phenomenon that was difficult to realize with conventional physical systems.In the first half of this talk, we introduce our recent work on a Thouless quantum pump induced by "(quasi-periodic) turbulence". The Thouless quantum pump is a topological quantum phenomenon corresponding to the quantum Hall effect in space and time dimensions, and has been recently realized in ultracold atomic system.(S. Nakajima et al., Nat. Phys.(2016)). Topological quantum phenomena are generally robust to perturbations such as "turbulence". On the other hand, in recent years, a new type of topological quantum phenomenon (eg, topological Anderson insulator etc.) has emerged for the first time due to the existence of "turbulence". We investigated the effect of (quasiperiodic) turbulence on a Thouless quantum pump using ultracold atomic system in an optical lattice. Furthermore, by applying the results, we constructed a Thouless quantum pump system that first appeared in the presence of "turbulence". In the latter half of the talk, if time allows, I would like to give a brief introduction to the new cooled Li atom experimental system equipment and its goals that I am currently setting up based on two projects.
The number of participants:38
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Endo (Tohoku Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Nakajima (Kyoto Univ.), Fukuhara (RIKEN), Fujimoto (Nagoya Univ.), Horikoshi (Osaka City University)


The 1st Cold atom workshop "Atom-NO-KAI"

Date:September 18, 2019 (Wed.), 19th (Thu.), 20th (Fri.) 2019
Place: Atami
Program: pdf
Scope: In order to take a leap forward in domestic cold atom research, we will hold a workshop "Atom-NO-KAI("Atom meeting")" where researchers and students gather and discuss with each other. The "Atom-NO-KAI" is not just a place to present your recent achievements, but rather aimed for good place to introduce new ideas, and to obtain suggestions from others. It should be a good place for experimentalists and theorists to work together. The scope of the workshop also includes encouraging young people, revitalizing the community, and becoming the first place for Japanese researchers to obtaining new ideas. This time we invite Dr. Takeshi Furukawa of Toho University, who specializes in polyatomic ion spectroscopy, and Dr. Ken Mizushima of Osaka University, who specializes in topological superfluids. Also, as a new project for students, one of the organizers (Inouye) will hold lectures for students.
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Kato (Osaka City Univ.), Kishimoto (UEC), Fukuhara (RIKEN), Horikoshi (Osaka City Univ.)
Co-sponsorship:Grant-in-Aid for Scientific Research on Innovative Areas "Clustering as a window on the hierarchical structure of quantum systems"




The 0th Cold Atom workshop

Date:September 20(Thu), 21st (Fri), 2018
Place: Karuizawa
Scope:More than 20 years have passed since the realization of Bose condensation of alkali atoms, and recent researches on cold atoms are becoming more and more challenging. Supporting this trend in Europe and the United States is the active exchange of human resources and the sharing of information and know-how through various organizational efforts. Although we feel Japan is somewhat isolated from the rest of the world, we believe it is possible to establish a new forum for discussion, and we will be able to make a leap in research and foster the next generation. This time, which was called the 0th session, we will share information through intense discussions on active area of research.
Program
Organizers(In alphabetical order): Inouye (Osaka City Univ.), Kishimoto (UEC), Fukuhara (RIKEN), Horikoshi (The Univ. of Tokyo)