MCNAMARAC 144-1 (office), 624-7567
qian @ physics.umn.edu
Fellow of American Physical Society (since 2008)
McKnight Presidential Fellow, University of Minnesota (2004-06)
Department of Energy Outstanding Junior Investigator (2000-04)
Editorial Committee for Annual Review of Nuclear and Particle Science (2015-19)
Editorial Board for Science China - Physics, Mechanics and Astronomy (since 2013)
National Advisory Committee for the Institute for Nuclear Theory (INT), University of Washington, Seattle (2007-09)
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)
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
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.
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.
A lecture on Neutrinos & Supernova Nucleosynthesis:
A lecture on The r-Process: Status & Challenges:
A lecture on Hierarchical Structure Formation & Chemical Evolution of Galaxies:
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).