Strong liberal arts school, the first unit re-issued Science

Source: East China Normal University

American time August 26, the international physics authoritative academic journal "Science" (Science) magazine published in the form of "First Release" 13span East China Normal University State Key Laboratory of Precision Spectroscopy Science and Technology Professor Wu Haibin’s research results "The observation of super-radiative quantum phase transition of ultra-cold degenerate Fermi gas in an optical cavity". This is after the publication of "Observation of Efimovian Expansion in Fermi Gas with Constant Scale" in 2016, the results of Wu Haibin's team took East China Normal University as the first completion unit and then published the main issue of "Science".

"First Release" Wu Haibin's research team in "Science" "First Release" revealed the first quantum of radiation in this study _span3sp _span0span _span0 p5 It is found that Pauli repulsion changes the scale rate of critical pump strength with atomic number, which provides an ideal platform for studying the non-equilibrium dynamics of Fermi states in long-range interactions.

"This is an important milestone"

The research work revealed for the first time the role of quantum statistics in superradiative quantum phase transitions.It is found that Pauli repulsion changes the scale rate of the critical pump strength with the number of atoms, which provides an ideal platform for studying the non-equilibrium dynamics of Fermi states with long-range interactions, and will open many new research directions.

This research was evaluated by the reviewers as "this is an important milestone, which paves the way for the realization of quantum simulations of many-body physics of fermions with long-range interactions using photonic media interactions. "

Another reviewer commented that "This is a long-awaited experiment to observe what was previously predicted only theoretically"; "The influence of Fermi statistics on the observed dissipative phase transition This will open up an entire field that can only be considered theoretically so far. Many exciting observations, such as the dissipative stability of topological phases or spin liquid phases, will follow."

Quantum statistics have been observed for the first time in experiments

Ultra-cold Quantum The combination of gas and cavity quantum electrodynamics provides an ideal system for studying novel phase transitions in many-body physics. An iconic example is the famous Dicke model, which describes the collective interaction between the light field and atoms. Under strong coupling, a second-order quantum phase transition between the normal and steady-state superradiative phases can occur. .

But since this superradiative quantum phase transition was proposed in 1973, it has not been observed experimentally. It was not until 2010 that the Dicke phase transition was realized in the Bose-Einstein condensate ( BEC ) using the momentum state of the ultra-cold atom.

Another type of atom in nature that corresponds to the Bose atom, Fermi atom, and its combination with cavity quantum electrodynamics. Although it has long attracted the attention of scientists, experimental research It is extremely challenging.

Whether matter wave can be amplified in Fermi atoms was a big controversy in the scientific field 20 years ago; in 2014, three theoretical groups predicted degenerate Fermi There is a steady-state superradiative phase in the gas, and its atomic quantum statistics and the nesting of the optical lattice play an important role. However, quantum statistics has not been observed experimentally.

Professor Wu Haibin’s research group focused on this challenge in 2013. After years of hard work, it has overcome the precision control technology of the optical cavity in the ultra-cold quantum gas complex system, and is the first to achieve ultra The strong coupling between the cold Fermi atoms and the optical cavity. During the research, a control method for precisely controlling the temperature of the ultra-cold Fermi gas in the optical cavity was developed. The superradiative quantum phase transition of Fermi atoms was observed for the first time, and more importantly, the first This time reveals the role of atomic statistics in superradiation quantum phase transition.

Continue to tackle key problems, and be listed in "Science" twice in five years

State Key Laboratory of Precision Spectroscopy Science and Technology, relying on East China Normal University and international strategic frontiers in science and technology , Formed a "high-precision", "high-resolution" and "high-sensitivity" precision spectroscopy research platform, developed new technologies for precise time-frequency control and measurement of light fields, and revealed new mechanisms and new effects of the interaction between light fields and matter.Explore major applications such as aerospace and national defense security.

In order to hit the world’s first echelon and lead the construction of an excellent university, this Guozhong laboratory team has always aimed at national mission tasks and facing the frontiers of science in the world. effort.

In this study, East China Normal University was the first to complete the study, the cooperating unit was Graduate School of China Academy of Engineering Physics , the first doctoral student Zhang Xiaotian was the thesis. Professor Wu Haibin is the corresponding author of the paper.

Wu Haibin was supported by the East China Normal University "Young High-Level Talents Program" in 2012 and was selected into the "Overseas High-Level Talents Introduction" program of the Organization Department. With the support of the school and relying on the State Key Laboratory of Precision Spectroscopy Science and Technology, Wu Haibin established an experimental platform for the precise control of ultra-cold atoms and molecules, and organized a team to continue to tackle key problems and study the experimental research of strong interaction ultra-cold quantum gases, 2019 In the year, he was funded by the Outstanding Youth Fund of the National Natural Science Foundation of China.

Professor Wu Haibin, State Key Laboratory of Precision Spectroscopy Science and Technology, East China Normal University _span1 span

5His team has made a series of important research progress in the non-equilibrium dynamics of strong multi-body interactions and quantum thermodynamics: experiments have discovered the universal Efimovian expansion dynamics of strongly interacting ultra-cold Fermi gases [Science 353,371(2016) ] And super Efimovian expansion dynamics [Phys. Rev. Lett. 120, 125301 (2018)]; the first realization of quantum adiabatic shortcut and the dissipation of work done by a strongly correlated multi-body heat engine in a strongly interacting ultra-cold Fermi gas [Science Advances 4, eaar5009 (2018)]; A new type of long-range controllable heat transfer that is different from traditional heat transfer mechanisms is realized [Nat. Commun. 11, 4656 (2020), Phys. Rev. Lett. 124, 053604 (2020) ].

has accumulated rich research experience in the strong interaction and ultra-cold quantum gas non-equilibrium many-body dynamics and thermodynamic manipulation. The other author of this paper is Deng Shujin, a young researcher who is the first doctoral graduate of Professor Wu Haibin and is a young Zijiang scholar of our school (2017).

This work has been awarded the Ministry of Science and Technology Quantum Control Key Special Project, National Natural Science Foundation Key Project, National Natural Science Foundation of China Outstanding Youth Fund Project, Shanghai Municipal Major Special Project and Major Basic Research Project funding.

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