Postdoctoral and Research Fellows

Weihong Zheng

BSc China, PhD China

Senior Research Associate

Department

Particle Physics

Theoretical Physics

Research Interests

His main research interest involves the study of various lattice models on theoretical physics, this includes the lattice spin and fermion models in the condensed matter physics, and the lattice gauge theory in particle physics. Some of these models in condensed matter physics are related to the macroscopic quantum phenomena such as magnetism and superconductivity, while others in quantum field theory describe the strong interactions within the sub-nuclear particles. The study of these systems relies on a variety of analytic and numerical techniques requiring the use of supercomputer. 

His research group has been among the world pioneers in developing linked-cluster expansion methods for generating perturbation series in Hamiltonian lattice models. Using this technique, they have generated the longest series available for a variety of spin and gauge models. For the Heisenberg antiferromagnet, their series results are very accurate, rivalling or exceeding the best Monte Carlo estimates. His research group has also developed the longest spin-wave perturbation series for several lattice models.

Recently, his research group has successfully developed a linked-cluster series expansion technique to study the properties of multi-particle bound states and continuum.  The study of multi-particle bound states remains a challenging problem in many-body physics. The information of multi-particle bound states is very important for understanding the nature of low temperature quantum ground states in real experimental systems, while a controlled numerical framework for the calculation of multi-particle spectral properties, which can also account for various singularities as the coupling constants are varied, is currently missing. The development of high-order series expansion for multi-particle bound states present significant advances. With this new technique, they have found several new bound states on various systems, and this approach appears to be a most productive and exciting line of development.

He is also interested on other numerical techniques, including the the density matrix renormalization group method, the spin-wave theory, the t-expansion method , and the finite lattice approach. 

Selected Publications

  • The square lattice Heisenberg antiferromagnet at T=0. W.H. Zheng, J. Oitmaa and C.J. Hamer, Physical Review, B43, 8321-8330(1991).
  • Spin-wave theory and finite-size scaling for the Heisenberg antiferromagnet. W.H. Zheng and C.J. Hamer , Physical Review, B47, 7961-7970(1993).
  • Strong coupling series for Abelian lattice gauge models in 3+1 dimensions. C.J. Hamer, J. Oitmaa and W.H. Zheng, Physical Review, D49, 535-542 (1994).
  • Convergent expansions for properties of the Heisenberg model for CaV4O9. M.P. Gelfand, W.H. Zheng, R.R.P. Singh, J. Oitmaa and C.J. Hamer, Physical Review Letter, 77, 2794-2797 (1996)
  • Various series expansions for the bilayer S=1/2 Heisenberg antiferromagnet. W.H. Zheng, Physical Review B55, 12267-12275 (1997).
  • Novel Approach to Description of Spin-Liquid Phases in Low-Dimensional Quantum Antiferromagnets. V.N. Kotov, O. Sushkov, W.H. Zheng and J. Oitmaa, Physical Review Letter, 80, 5790-5793 (1998).
  • Multi-layer S=1/2 Heisenberg antiferromagnet, W.H. Zheng, Physical Review B59, 387-395(1999).
  • Strong-Coupling Expansions for Multiparticle Excitations: Continuum and Bound States, S. Trebst, H. Monien, C.J. Hamer, W.H. Zheng, R.R.P. Singh, Physical Review Letter, 85, 4373-4376(2000).
  • Linked cluster series expansions for two-particle bound states,
    W.H. Zheng, C.J. Hamer, R.R. P. Singh, S. Trebst, and H. Monien, Physical Review B63, 144410 (2001).
  • Deconfinement transition and bound states in frustrated Heisenberg chains: regimes of forced and spontaneous dimerization, W.H. Zheng, C.J. Hamer, R.R.P. Singh, S. Trebst, and H. Monien,  Physical Review B63, 144411 (2001).
  • Realization of a large J2 quasi-2D spin-half Heisenberg system: Li2VOSiO4, H. Rosner, R.R. P. Singh, W. H. Zheng, J. Oitmaa, S. L. Drechsler, W. E. Pickett, Physical Review Letter, 88, 186405 (2002).
  • Spectral weight contributions of many-particle bound states and continuum, W.H. Zheng, C.J. Hamer, and R.R.P. Singh, accepted in Physical Review Letter.

Contact Details 

Mail Address

School of Physics
The University of New South Wales
SYDNEY 2052
Australia

Personal Web Site

Email Address

Phone Number

61 2 9385 4562

Facsimile Number

61 2 9385 6060