- Visiting

## Chris Hamer

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## Department:

## Subjects Taught:

## Teaching:

I continue to teach a General Education course on

"Nuclear Arms, Peace and Global Governance"

## Education:

- MSc Melb.,
- PhD Calif. Inst. Tech.,
- GradDipCompSc Canberra, FAIP

## Research Interests:

My research interests lie in theoretical physics, at the interface between particle physics and statistical mechanics. Our group studies quantum lattice models, which may represent atomic spins in a magnet, electrons in a superconductor, or quarks confined within the proton. Various methods of treating such models have been employed including series expansions, Monte Carlo simulations, exact diagonalization and the density matrix renormalization group (DMRG). We are also interested in "effective field theories" for systems at a critical point.

We have published a book on series expansion techniques, ‘Series Expansion Methods for Strongly Interacting Lattice Models’, by Jaan Oitmaa, Chris Hamer and Weihong Zheng (Cambridge University Press, 2006). Much of our computational work in this area was carried out by our late friend and colleague, Dr Weihong Zheng, who collected many of his codes used in this field at his personal website.

Being now retired, I am no longer taking graduate students, but am continuing research on a part-time basis. One current interest is the construction of an effective field theory for the ‘Union Jack’ spin model.

I am also active in civil society movements. I am the founder of the World Citizens Association (Australia) and President in a caretaker capacity) of Scientists for Global Responsibility (Australia), as well as Chairman of the Institute for Global Peace and Sustainable Govenance. I am convinced that we need a global parliament to deal with our pressing global issues, and have published a book on e subject:

"Ä Global Parliament: Principles of World Federation" (Oyster Bay Press 1998), now available on Amazon. Some of this material is discussed in my General Education course GENS 4008 *'Nuclear Arms, Peace and Global Governance'*.

## Honours, Awards and Memberships:

FAIP

## Selected Publications:

Hamer, C.J., 1973. Explicit solution of the statistical bootstrap model via Laplace transforms. Phys. Rev. D8: 3558-3568.

Hamer, C.J., 1978. Connected diagram expansion for lattice Hamiltonian models. Nucl.Phys. B146: 492-508.

Hamer, C.J., Kogut, J.B. and Susskind, L., 1978. The phases of 2-dimensional Heisenberg spin systems from

strong-coupling expansions. Phys. Rev. Letts. 41: 1337-1340.

Hamer, C.J., 1979. Estimating eigenvalues for lattice Hamiltonians. Phys. Letts. 82B: 75-78.

Crewther, D.R.P. and Hamer, C.J., 1980. Eigenvalues for the massive Schwinger model from a finite-lattice Hamiltonian

approach. Nucl. Phys. B170: 353-368.

Hamer, C.J. and Barber, M.N., 1980. Finite-size scaling in Hamiltonian field theory. J.Phys. A13: L169-174.

Hamer, C.J. and Barber, M.N., 1981. Finite-lattice methods in quantum Hamiltonian field theory. I. The Ising model.

J.Phys. A14: 241-258.

Hamer, C.J., Kogut, J., Crewther, D.P. and Mazzolini, M.M, 1982. The massive Schwinger model on a lattice:

background field, chiral symmetry and string tension. Nucl. Phys. B208: 413-438.

Hamer, C.J. and Irving, A.C., 1984. Methods in Hamiltonian lattice field theory. I. Connected diagram expansions.

Nucl.Phys. B230: 336-360.

Irving, A.C. and Hamer, C.J., 1984. Methods in Hamiltonian lattice field theory. II. Linked-cluster expansions.

Nucl.Phys. B230: 361-384.

Hamer, C.J., Irving, A.C. and Preece, T.E., 1986. Cluster expansion approach to non-Abelian lattice gauge theory in

(3+1)D. II. SU(3). Nucl.Phys. B270: 553-574.

Hamer, C.J., Quispel, G.R.W., and Batchelor, M.T., 1987. Conformal anomaly and surface energy for Potts and

Ashkin-Teller quantum chains. J.Phys. A20: 5677-5693.

Hamer, C.J. and Batchelor, M.T., 1988. Some finite-size amplitudes and critical exponents for Potts and Ashkin-Teller

quantum chains. J.Phys. A21: L173-178.

Hamer, C.J., Zheng, W. and Arndt, P., 1992. Third-order spin-wave theory for the Heisenberg antiferromagnet.

Phys. Rev. B46: 6276-6292.

Zheng, W., and Hamer, C.J., 1993. Spin-wave theory and finite-size scaling for the Heisenberg antiferromagnet.

Phys.Rev. B47: 7961-7970.

Bursill, R.J., McKenzie, R.H. and Hamer, C.J., 1998. Phase Diagram of the One- Dimensional Holstein model of

Spinless Fermions. Phys. Rev. Letts. 80, 5607-5610.

Sandvik, A.W., and Hamer, C.J., 1999. Ground-state parameters, finite-size scaling, and low-temperature behavior

of the two-dimensional S=1/2 XY-model. Phys. Rev. B60, 6588-93.

Sriganesh, P., Bursill, R.J. and Hamer, C.J., 2000. A new finite-lattice study of the massive Schwinger model.

Phys. Rev. D62, 034508-1-9.

Hamer, C.J., 2000. Finite-size Scaling in the transverse Ising model on a square lattice. J. Phys. A33, 6683-98.

Trebst, S., Monien, H., Hamer, C.J., Zheng, W. and Singh, R.R.P., 2000. Strong-Coupling Expansions for

Multiparticle Excitations: Continuum and Bound States. Phys. Rev. Letts. 85, 4373-76.

Zheng, W., Hamer, C.J., Singh, R.R.P., Trebst, S. and Monien, H., 2001. Linked Cluster Series Expansions for

Two-Particle Bound States. Phys. Rev. B63, 144410-1-13.

Byrnes, T.M.R., Sriganesh, P., Bursill, R., and Hamer, C.J., 2002. Density matrix renormalization group approach

to the massive Schwinger model. Phys. Rev. D66, 013002 1-14

Zheng WH, Hamer CJ, Singh RRP, et al., 2003. Linked cluster series expansions for two-particle states in quantum

lattice models, Int. J. Mod. Phys. 17, 5011-5020.

Byrnes, T.M.R., Loan, M., Hamer, C.J., Bonnet, F.D.R., Leinweber, D.B., Williams, A.G. and Zanotti, J.M., 2004.

Hamiltonian limit of (3+1)-dimensional SU(3) lattice gauge theory on anisotropic lattices. Phys. Rev. D69, 074509-1-9.

Zheng, W-H., Oitmaa, J. and Hamer, C.J., 2005. Series study of the spin-1/2 Heisenberg antiferromagnet at T=0:

Magnon dispersion and structure factors. Phys. Rev. B71, 184440-1-10.

Zheng, W-H., Oitmaa, J., and Hamer, C.J., 2007. ‘Phase diagram of the frustrated Heisenberg antiferromagnet on the

union jack lattice’, Phys. Rev. B75, 184418-1-10.

Hamer, C.J., Oitmaa, J., and Zheng Weihong, 2012. ‘Restoration of symmetry in the spectrum of the bilayer Heisenberg

antiferromagnet’, Phys. Rev B85, 014432.

Books:

Oitmaa, J., Hamer, C.J. and Zheng, W-H., 2006. ‘Series Expansion Methods for Strongly Interacting Lattice Models’,

(Cambridge University Press)

Non-Physics papers/books:

Chris Hamer, ‘Reinforcing the NPT’, Australian Journal of International Affairs 65:5, 578-589 (2011).

Chris Hamer, ‘Transforming NATO and the OECD into a World Community of Democracies’, Freedom & Union,

Series II, Vol. 1, no. 1, p. 9 (2011).

Christopher Hamer, ‘A Global Parliament: Principles of World Federation’ (Amazon)