# Professor Xi-Wen Guan

Position | Honorary Professor |
---|---|

Department | Fundamental & Theoretical Physics |

Research group | Mathematical physics group |

Office phone | (02) 612 52968 |

Office | Oliphant 4 11 |

## Biography

Xiwen Guan was born in Qingdao, China. He completed his undergraduate study with a Bachelor of Science in Physics and High Education at Qufu Normal University in China in 1986. After graduation, he was assigned to teach physics at the Qingdao Technology College in his hometown. He received several Awards for Excellence in Teaching in the College. He was promoted to associate professor in 1992 due to his excellence in teaching.

Guan undertook his PhD study at Jilin University during 1995-1998. He graduated from Jilin University with PhD degree in Theoretical Physics in November, 1998. He was awarded the ``Baogang Education Foundation'' prize from Baogang Education Commission of P. R. China due to his excellent research outcomes. He then undertook postdoctoral research for 3 years at the Technische Universitat Chemnitz, Germany, the Universidade Federal de Sao Carlos, Sao Paulo and the Universidade Federal do Rio Grande do sul, Porto Alegre, Brasil. Since his appointment at ANU in February 2003, Guan has been working in the areas of mathematical physics and exactly solvable models in condensed matter, statistical mechanics, cold atoms and spin liquids. He was promoted to Level C Fellow effective from January 2009.

Guan has held/ holds several visiting positions: 1) a visiting professor position at Tsinghua University, China for 4 months every year from 2012 to 2014; 2) a visiting scientist position at Ohio State University for 3 months in 2010; 3) a regular visitor to the Institute of Physics, Chinese Academy of Science, Beijing from 2009 to 2011.

From 2011, Guan is serving on the Advisory Panel of Journal of Physics A.

## Research interests

- Exactly solvable models in cold atoms, strongly correlated electron systems, spin chains, vertex models, spin ladder compounds.
- Haldane exclusion statistics, Tomonaga-Luttinger liquids, quantum criticality and quantum correlation functions.
- Quantum metrology, quantum information.
- Quantum algebra, quantum groups, open boundary quantum inverse scattering method, quantum transfer matrix.

Guan has made a number of contributions in these fields, which have led to direct applications in recent breakthrough experiments on 1D many-body physics. To mention few examples:

1. He, in collaboration with Murray Batchelor and Chaohong Lee, published a review article [Rev. Mod. Phys. 85, 1633 (2013) (58 pages)] which views the theoretical and experimental developments for interacting fermions in 1D. It shows that exact results obtained for Bethe ansatz integrable models that enable study of a wide range of quantum many-body phenomena driven by dynamical interactions, quantum statistics and magnetic fields, including the Tomonaga-Luttinger liquids, spin-charge separation, FFLO-like pair correlations, quantum criticality and scaling, polarons, and few-body physics of trimer states (trions) as well as experiments of trapped Fermi gases.

2. The work “Guan, et. al., Phys. Rev. B 76, 085120 (2007)” predicted the novel quantum phase diagram and ground properties for the Yang-Gaudin model which was later confirmed by the experimental group led by R. Hulet at Rice University [Nature 467, 567 (2010)].

3. In 2005, he (with Batchelor et al., Journal of Statistical Mechanics (2005) L10001) theoretically proved the existence of the novel super Tonks-Girardeau (TG) gas in a 1D Bose gas which was confirmed in the remarkable experiments with ultracold Cesium atoms by E. Haller et al. in Science 325, 1224 (2009) and with dipole-diole interacting Dysprosium atoms by Kao et al. Science 371, 296 (2021).

4. He with the collaborators from the experimental group at University of Science and Technology of China [Phys. Rev. let. 119, 165701 (2017)] for the first time observed quantum scaling laws and Luttinger liquid correlations through the 1D interacting Bose gas of ultracold atoms. This paper was elected as Editor’s suggestion and the Viewpoint on the importance of our work was given by Professor Thierry Giamarchi at (https://physics.aps.org/articles/v10/115). The European Physical Society Physicsworld published a highlight on this paper “Atoms and Josephson junctions simulate 1D quantum liquid”.

5. He with collaborators developed both phenomenological and Bethe ansatz technical approaches to multicomponent Bose and Fermi gases, including universal thermodynamics [Phys. Rev. Lett. 103,140404 (2009)], quantum liquids [Phys. Rev. Lett. 111, 130401 (2013)], critical correlation Nat. Commun. 5, 5140 (2014, spin coherent and incoherent liquid [Phys. Rev. Lett. 125, 190401 (2020)], SU(N) Fermi gases [Physical Review Letters 100 (2008) 200401, Phys. Rev. A, 85, 033633 (2012), J. Phys. A, 39, 1073 (2006), J. Phys. A 49 (2016) 174005]. The work on SU(N) Fermi gases has provided useful theoretical input for recent experiment in Nat. Phys. 10,198 (2014) and Phys. Rev. X 10, 041053 (2020).

6. His collaborative work “Adv. Phys. 56，465-543 (2007), 78 pages ”, gave a major review of the mathematical machinery of exactly solved models in statistical mechanics and applied exact high-temperature expansion approach to the physics of spin ladder compounds. The theoretical predictions [Phys. Rev. Lett. 91,217202 (2003)] were shown to be in very good agreement with experimental results for many known spin ladder compounds with strong rung coupling and for gapped spin chain materials with strong anisotropies.

7. In his recent paper “Phys. Rev. B 96, 220401(R) (2017)”, he with collaborators analytically calculated scaling functions of thermal and magnetic properties of 1D Heisenberg chains, providing a rigorous understanding of the quantum criticality of spinons. This prediction was experimentally confirmed shortly in Sci. Adv. 3, eaao3773 (2017) and quickly received many citations from the top journals including Nature, Phys. Rep., Phys. Rev. Lett., etc.

8. In 2006, he with Batchelor, [Phy. Rev. Lett. 96, 210402 (2006), Phys. Rev. B 74, 195121 (2006)], initiated a highly successful project on interacting anyons in 1D. They proved that 1D interacting anionic gases, including interacting bosons and fermions, are equivalent to ideal particles obeying Haldane fractional statistics. This provided deep insight towards understanding quantum statistics and dynamics in many-body physics and led to further developments by theorists in many countries (USA, France, Germany, UK, China, etc). He with his collaborators recently also found that the non-mutual Haldane fractional statistics naturally occurs at quantum critical regime of 1D, 2D, and 3D interacting Bose gases. This builds up a general connection between the Haldane fractional statistics and particle-hole symmetry breaking.

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