Yubo

Yubo "Paul" Yang

Assistant Professor

Posts by Collection

portfolio

publications

How large are nonadiabatic effects in atomic and diatomic systems?

Published in The Journal of Chemical Physics, 2015

We simulated small (<10 e) atoms and molecules in their ground states, treating the electrons and ions on the same footing, i.e. without invoking the Born-Oppenheimer approximation.

Recommended citation: Y. Yang, I. Kylänpää, N. M. Tubman, J. T. Krogel, S. Hammes-Schiffer, and D. M. Ceperley, "How large are nonadiabatic effects in atomic and diatomic systems?, " J. Chem. Phys. 143, 124308 (2015). https://aip.scitation.org/doi/10.1063/1.4931667

Electronic band gaps from Quantum Monte Carlo methods

Published in Phys. Rev. B, 2019

We prove the leading-order scaling of the fundamental gap based on the asymptotic behavior of changes in the electronic structure factor S(k) in the long wavelength limit (k=0). We further directly calculate finite-size correction to leading and sub-leading orders using only S(k) at one system size.

Recommended citation: Y. Yang, V. Gorelov, C. Pierleoni, D. M. Ceperley, and M. Holzmann, "Electronic band gaps from Quantum Monte Carlo methods, " Phys. Rev. B 101, 085115 (2020). https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.085115

Direct observation of the momentum distribution and renormalization factor in lithium

Published in Phys. Rev. B, 2020

We facilitated the first unambigous direct observation of the renormalization factor Zkf in lithium by using QMC to validate and correct experimental Compton profile near the Fermi break, where severe smearing from resolution and final state effects denied definitive observation of the momentum discontinuity in previous studies.

Recommended citation: N. Hiraoka, Y. Yang, T. Hagiya, A. Niozu, K. Matsuda, S. Huotari, M. Holzmann and D. M. Ceperley, "Quantum Monte Carlo Compton profiles of solid and liquid lithium, " Phys. Rev. B 101, 165124 (2020). https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.165124

Quantum Monte Carlo Compton profiles of solid and liquid lithium

Published in Phys. Rev. B, 2020

We calculated the momentum distribution n(k) of BCC lithium using all-electron QMC in the grand-canonical ensemble. Kinetic sum rule from finite-size corrected n(k) agrees with thermodynamic limit to 0.1 mha/e. BFD solid - liquid difference agrees well with experiment, but the pseudopotential Compton profile is too narrow due to lack of orthogonalization with core states.

Recommended citation: Y. Yang, N. Hiraoka, K. Matsuda, M. Holzmann, D. M. Ceperley, "Quantum Monte Carlo Compton profiles of solid and liquid lithium, " Phys. Rev. B 101, 165125 (2020). https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.165125

research

talks

teaching

PHYS 460 Condensed Matter Physics

Class, University of Illinois Urbana Champaign, Physics Department, 2019

I was the lone TA for this class. I reworked many HW problems and made the solutions. We covered most materials in “The Oxford Solid State Basics” by Steven Simon.

thesis