skip to content
 

Professor Ali Alavi

Portrait of asa10

The work of our group is primarily focused on the electron correlation problem - namely how to compute the correlation energy for an atom, molecule, or even solid, starting from a mean-field (say Hartree-Fock) description of the system. Our approach is to combine quantum chemical ideas with stochastic (Monte Carlo) techniques, which enable us to tackle problems which are very difficult to solve use standard quantum chemical techniques alone.

We are developing Quantum Monte Carlo algorithms adapted for electronic (and more generally Fermionic) problems by working in Slater determinant spaces. The central problem which is encountered is the infamous "Fermion sign problem", which results from electronic wavefunctions having both positive and negative amplitudes. Currently we are working on a novel population dynamics algorithm which propagates walkers in Slater determinant space according to a type of "stochastic cellular automaton" obeying simple rules. The movie on the home page shows an evolving population of walkers of positive and negative sign settling on the FCI wavefunction of a nitrogen dimer in a minimal basis - an archetypal multireference system. The remarkable aspect of this dynamics is the spontaneous symmetry breaking caused by annhilation processes, allowing the exact nodal surface of the nitrogen molecule, as expressed by the CI coefficients, molecule to appear. No fixed-node approximation is applied.

Further animations of this method in action can be viewed here.

 

Teaching

 

Please click on: http://www-alavi.ch.cam.ac.uk/teaching

 

Publications

 

Please click on: http://www-alavi.ch.cam.ac.uk/publications

Publications

Linear-scaling and parallelisable algorithms for stochastic quantum chemistry
GH Booth, SD Smart, A Alavi – Molecular Physics (2014)
Explicitly correlated plane waves: accelerating convergence in periodic wavefunction expansions.
A Grüneis, JJ Shepherd, A Alavi, DP Tew, GH Booth – The Journal of chemical physics (2013) 139, 084112
A single-source route to bulk samples of C3N and the co-evolution of graphitic carbon microspheres
TC King, PD Matthews, JP Holgado, DA Jefferson, RM Lambert, A Alavi, DS Wright – Carbon (2013) 64, 6
Towards an exact description of electronic wavefunctions in real solids.
GH Booth, A Grüneis, G Kresse, A Alavi – Nature (2013) 493, 365
Emergence of Critical Phenomena in Full Configuration Interaction Quantum Monte Carlo
JJ Shepherd, LR Schwarz, RE Thomas, GH Booth, D Frenkel, A Alavi – (2012)
An explicitly correlated approach to basis set incompleteness in full configuration interaction quantum Monte Carlo
GH Booth, D Cleland, A Alavi, DP Tew – The Journal of chemical physics (2012) 137, 164112
Investigation of the full configuration interaction quantum Monte Carlo method using homogeneous electron gas models.
JJ Shepherd, GH Booth, A Alavi – J. Chem. Phys. (2012) 136, 244101
Self-assembly at room temperature of thermally stable discrete and extended oligomers of polycyclic aromatics on Ag(100): induced dipoles and cooperative effects.
AC Papageorgiou, A Alavi, RM Lambert – Chemical communications (Cambridge, England) (2012) 48, 3394
Full configuration interaction perspective on the homogeneous electron gas
JJ Shepherd, G Booth, A Gruneis, A Alavi – Physical Review B - Condensed Matter and Materials Physics (2011) 85, 081103
Convergence of many-body wave-function expansions using a plane-wave basis: From homogeneous electron gas to solid state systems
JJ Shepherd, A Grüneis, GH Booth, G Kresse, A Alavi – Physical Review B - Condensed Matter and Materials Physics (2012) 86, 035111
  •  
  • 1 of 10
  • >

Research Group

Research Interest Group

Telephone number

01223 762877

Email address

asa10@cam.ac.uk