Yong-Zhong Qian

Yong-Zhong Qian

Yong-Zhong Qian

Professor, School of Physics and Astronomy

Contact

John T. Tate Hall
Room 375-18
116 Church Street Se
Minneapolis, MN 55455

Affiliations

Minnesota Institute for Astrophysics (MIfA)
Education

Ph.D., University of California, San Diego, 1993

B.S., University of Science and Technology of China, 1989 

Professional Background

Editorial Committee for Annual Review of Nuclear and Particle Science, 2015-2024

Editorial Board for Science China - Physics, Mechanics and Astronomy, 2013-2022

Editorial Board for Physical Review C, 2018-2020

Annual Summer School on Computational Astrophysics and Related Workshop, Tsung-Dao Lee Institute, Shanghai, China, 2017-2019

Nucleosynthesis and Chemical Evolution, 5-week INT program, University of Washington, Seattle, 2014

The Origin of the Elements: A Modern Perspective, European Center for Theoretical Studies in Nuclear Physics and Related Areas workshop, Trento, Italy, 2011

National Advisory Committee for the Institute for Nuclear Theory (INT), University of Washington, Seattle, 2007-2009

Fellow, American Physical Society, 2008

The First Stars and Evolution of the Early Universe, 5-week INT program, University of Washington, Seattle, 2006


Google Scholar: https://scholar.google.com/citations?user=PzOAIxUAAAAJ

Scientific & Professional Societies
Fellow, American Physical Society
Research Interests

Our Solar System: What Triggered Its Formation?

About 4.6 billion years ago, some event disturbed a cloud of gas and dust, triggering the gravitational collapse that led to the formation of the solar system. One hypothesis is that a nearby supernova - a star exploding at the end of its life cycle - initiated this event. My collaborators and I have examined why earlier forensic evidence based on studies of extinct radioactive nuclei in meteorites have been inconclusive, and shown how recent results from modeling supernovae and their impact on star formation have opened up new directions in researching the formation of our solar system.

Click here for a news report on our work and here for our paper published in Nature Communications.


Flavor Oscillations of Astrophysical Neutrinos

Using neutrinos produced by nuclear reactions in the sun, by interaction of cosmic rays with earth's atmosphere, and by accelerators and nuclear reactors on earth, a number of experiments showed that neutrinos oscillate among different flavors and therefore have mass. Yet some key parameters characterizing neutrino oscillations are unknown. New experiments such as MINOS and NOvA, in which the University of Minnesota plays a prominent role, are being carried out to probe these unknown parameters. Interestingly, supernovae that signify the explosive death of massive stars are prodigious sources of neutrinos and provide another venue to study neutrino oscillations. In fact, the number density of neutrinos near the core of a supernova is so large that new phenomena of neutrino oscillations arise. In particular, the flavor evolution for neutrinos of different energies traveling in different directions may be coupled together to produce collective oscillations. This new phenomenon is extremely sensitive to the unknown neutrino oscillation parameters, thereby allowing possible extraction of these parameters from the detection of neutrinos from a future supernova.


Diverse Supernova Sources for Neutrinos and Elements

A lecture on Neutrinos & Supernova Nucleosynthesis: https://www.youtube.com/watch?v=o-Y0clHDSqU


r-Process Nucleosynthesis

A lecture on The r-Process: Status & Challenges: https://www.youtube.com/watch?v=Q-G3zECnApw


Chemical Evolution of Galaxies

A lecture on Hierarchical Structure Formation & Chemical Evolution of Galaxies: https://www.youtube.com/watch?v=yq9PDIrahJg

Honors and Awards

McKnight Presidential Fellow, University of Minnesota, 2004-2006

Department of Energy Outstanding Junior Investigator, 2000-2004

Selected Publications

Z. Xiong, A. Sieverding, M. Sen, and Y.-Z. Qian, “Potential Impact of Fast Flavor Oscillations on Neutrino-driven Winds and Their Nucleosynthesis”, Astrophys. J. 900, 144 (2020).

Z.-Z. Li, Y.-Z. Qian, J. Han, T. S. Li, W. Wang, and Y. P. Jing, “Constraining the Milky Way Mass Profile with Phase-space Distribution of Satellite Galaxies”, Astrophys. J. 894, 10 (2020).

G. Guo, Y.-Z. Qian, and M.-R. Wu, “Neutrino Production Associated with Late Bumps in Gamma-Ray Bursts and Potential Contribution to Diffuse Flux at IceCube”, Astrophys. J. 890, 83 (2020).

P. Banerjee, A. Heger, and Y.-Z. Qian, “New s-Process Mechanism in Rapidly-Rotating Massive Population II Stars”, Astrophys. J. 887, 187 (2019).

Z.-Z. Li, Y.-Z. Qian, J. Han, W. Wang, and Y. P. Jing, “A Versatile and Accurate Method for Halo Mass Determination from Phase-Space Distribution of Satellite Galaxies”, Astrophys. J. 886, 69 (2019).

G. Guo, Y.-Z. Qian, and A. Heger, “Presupernova Neutrino Signals as Potential Probes of Neutrino Mass Hierarchy”, Phys. Lett. B 796, 126 (2019).

Z. Xiong, M.-R. Wu, and Y.-Z. Qian, “Active-Sterile Neutrino Oscillations in Neutrino-Driven Winds: Implications for Nucleosynthesis”, Astrophys. J. 880, 81 (2019).

E. Rrapaj, A. Sieverding, and Y.-Z. Qian, “Rate of Dark Photon Emission from Electron Positron Annihilation in Massive Stars”, Phys. Rev. D 100, 023009 (2019).

P. Banerjee, Y.-Z. Qian, and A. Heger, “New Neutron-capture Site in Massive Pop III and Pop II Stars as a Source for Heavy Elements in the Early Galaxy”, Astrophys. J. 865, 120 (2018).

P. Banerjee, Y.-Z. Qian, and A. Heger, “s-Process in Massive Carbon-Enhanced Metal-Poor Stars”, Mon. Not. Roy. Astron. Soc. 480, 4963 (2018).

Y.-Z. Qian, “Neutrinos, Supernovae, and the Origin of the Heavy Elements”, Sci. China-Phys. Mech. Astron. 61, 049501 (2018).

Z.-Z. Li, Y. P. Jing, Y.-Z. Qian, Z. Yuan, and D.-H. Zhao, “Determination of Dark Matter Halo Mass from Dynamics of Satellite Galaxies”, Astrophys. J. 850, 116 (2017).

P. Banerjee, Y.-Z. Qian, A. Heger, and W. C. Haxton, “Evidence from Stable Isotopes and Be-10 for Solar System Formation Triggered by a Low-Mass Supernova”, Nat. Commun. 7, 13639 (2016).

G. Guo and Y.-Z. Qian, “Spectra and Rates of Bremsstrahlung Neutrino Emission in Stars”, Phys. Rev. D 94, 043005 (2016).

Z. Yuan, Y.-Z. Qian, and Y. P. Jing, “Estimating the Evolution of Gas in the Fornax Dwarf Spheroidal Galaxy: An Illustrative Example”, Mon. Not. Roy. Astron. Soc. 456, 3253 (2016).

M.-R. Wu, H. Duan, and Y.-Z. Qian, “Physics of Neutrino Flavor Transformation through Matter-Neutrino Resonances”, Phys. Lett. B 752, 89 (2016).

M.-R. Wu, Y.-Z. Qian, G. Martinez-Pinedo, T. Fischer, and L. Huther, “Effects of Neutrino Oscillations on Nucleosynthesis and Neutrino Signals for an 18 Msun Supernova Model”, Phys. Rev. D 91, 065016 (2015).

M.-R. Wu, T. Fischer, L. Huther, G. Martinez-Pinedo, and Y.-Z. Qian, “Impact of Active-Sterile Neutrino Mixing on Supernova Explosion and Nucleosynthesis”, Phys. Rev. D 89, 061303(R) (2014).

Y.-Z. Qian, “Diverse, Massive-Star-Associated Sources for Elements Heavier than Fe and the Roles of Neutrinos”, J. Phys. G: Nucl. Part. Phys. 41, 044002 (2014).

P. Banerjee, Y.-Z. Qian, W. C. Haxton, and A. Heger, “New Primary Mechanisms for the Synthesis of Rare 9Be in Early Supernovae”, Phys. Rev. Lett. 110, 141101 (2013).

Y.-Z. Qian and G. J. Wasserburg, “Supernova-Driven Outflows and Chemical Evolution of Dwarf Spheroidal Galaxies”, Proc. Natl. Acad. Sci. USA 109, 4750 (2012).

P. Banerjee, W. C. Haxton, and Y.-Z. Qian, “Long, Cold, Early r Process? Neutrino-Induced Nucleosynthesis in He Shells Revisited”, Phys. Rev. Lett. 106, 201104 (2011).

H. Duan, G. M. Fuller, and Y.-Z. Qian, “Collective Neutrino Oscillations”, Annu. Rev. Nucl. Part. Sci. 60, 569 (2010).

H. Duan, G. M. Fuller, and Y.-Z. Qian, “Symmetries in Collective Neutrino Oscillations”, J. Phys. G: Nucl. Part. Phys. 36, 105003 (2009).

Y.-Z. Qian and G. J. Wasserburg, “Abundances of Sr, Y, and Zr in Metal-Poor Stars and Implications for Chemical Evolution in the Early Galaxy”, Astrophys. J. 687, 272 (2008).

H. Duan, G. M. Fuller, J. Carlson, and Y.-Z. Qian, “Flavor Evolution of the Neutronization Neutrino Burst from an O-Ne-Mg Core-Collapse Supernova”, Phys. Rev. Lett. 100, 021101 (2008).

H. Duan, G. M. Fuller, J. Carlson, and Y.-Z. Qian, “Neutrino Mass Hierarchy and Stepwise Spectral Swapping of Supernova Neutrino Flavors”, Phys. Rev. Lett. 99, 241802 (2007).

Y. Lu and Y.-Z. Qian, “Neutrino-Induced γ-Ray Emission from Supernovae”, Phys. Rev. D 76, 103002 (2007).

H. Ning, Y.-Z. Qian, and B. S. Meyer, “r-Process Nucleosynthesis in Shocked Surface Layers of O-Ne-Mg Cores”, Astrophys. J. Lett. 667, L159 (2007).

Y.-Z. Qian and G. J. Wasserburg, “Where, Oh Where Has the r-Process Gone?”, Phys. Rep. 442, 237 (2007).

H. Duan, G. M. Fuller, J. Carlson, and Y.-Z. Qian, “Simulation of Coherent Nonlinear Neutrino Flavor Transformation in the Supernova Environment: Correlated Neutrino Trajectories”, Phys. Rev. D 74, 105014 (2006).

Advisees & Collaborators

  • Axel Gross, Graduate Student
  • Jackson Olsen, Graduate Student
  • Ermal Rrapaj, Collaborator
  • Zewei Xiong, Graduate Student

Former Researchers and Students

Former Postdocs

  • Andre Sieverding (2018-20)
  • Projjwal Banerjee (2014-16)
  • James Kneller (2005-08)
  • Andrew Steiner (2002-04)

Former Graduate Students

  • Cheng-Hsien Li (2017)
  • Gang Guo (2016, Shanghai Jiao Tong University)
  • Zhen Yuan (2015)
  • Meng-Ru Wu (2012)
  • Projjwal Banerjee (2011)
  • He Ning (2007)
  • Yu Lu (2007)
  • Huaiyu Duan (2004)