Dr Andrew Ho

Research interests

My abiding quest is to understand quantum many-body physics. For my PhD (Rutgers University,USA) and after, I have been exploring theoretically unusual mecahnisms that destabilize the Fermi liquid---the "standard  model" of a metal. Such work has been motivated by the unconventional properties of the metallic state in materials such as the cuprate superconductors, and some new classes of heavy fermion materials. Recently, I have been exploring the unusual metal to metal transition that comes from a spontaneous deformation of the Fermi surface due to electron-electron interaction. (Reference [1])


Since 2003, and for my EPSRC Advanced Research Fellowship (2006-2011), I have focussed on theories of strong correlation in cold atom traps. The unprecedented experimental possibilities in coldatom gases open up many challenging avenues for studying quantum correlated systems: my current research take advantage of such unique possibilities to explore:
i) Quantum mixtures: unlike electron systems with only spin up or down, in atom traps mixtures of species can be loaded. Like solids, multipleBloch bands can be loaded. Interaction strength and even the sign can be continuously tuned. Novel forms of superfluidity and new states of matter could arise. See references [2,3,5,6].ii) Tunable dimensions: experiments on cold atoms allow the dimensionality to be tuned. One can follow how enhanced fluctuations special to 1D are suppressed, on going to higher dimensions. See reference [4].iii) Non-equilibrium behaviour: the long timescales of cold atomic gases allow non-equilibrium quantum systems to be probed, an opportunity largely denied to electrons in solids. See [7].

Since arriving at RHUL, I have been working closely with the Helium experimental groups of Professors Saunders, Cowan on modelling the strongly correlated states in these thin film experiments.

Recent key publications:
[1] A.F. Ho and A.J. Schofield,"Effect of disorder on a Pomeranchuk instability", Eur. Phys. Lett. 84, 27007 (2008)

[2] A.F. Ho, "Fermions in optical lattices near a Feshbach resonance: from band insulator to Mott insulator", Phys. Rev. A 73, 061601(R) (2006)

[3] M.A. Cazalilla, A.F. Ho, T. Giamarchi, "Two component Fermi gas on internal-state-dependent optical lattices'', Phys. Rev. Lett.  95, 226402 (2005)

[4] A.F. Ho, M.A. Cazalilla, T. Giamarchi, "Deconfinement in a 2D optical lattice of coupled 1D boson systems'', Phys. Rev. Lett.  92, 130405 (2004)

[5] M.A. Cazalilla and A.F. Ho, "Instabilities in binary mixtures of one-dimensional quantum fluids'', Phys. Rev. Lett.  91, 150403 (2003)

[6] M.A. Cazalilla, A.F. Ho, and M. Ueda, "Ultracold gases of Ytterbium: Ferromagnetism and Mott states in an SU(6)Fermi system", New Journal Phys., 11, 103033 (2009)

[7] S. Genway, A. F. Ho,  and D. K. K. Lee, "Dynamics of Thermalization in Small Hubbard-Model Systems", Phys. Rev. Lett. 105, 260402 (2010)

Teaching

Undergraduate:

PH3210 Quantum Theory  (together with Dr. Stephen West)

Psotgraduate:

Strongly correlated systems

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