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SUMMARY:Do we really need Quantum Computers to simulate Quantum Chemistry?
DTSTART:20150422T170000
DTEND:20150422T180000
DTSTAMP:20260406T212831Z
UID:629cd2b1f8ec0e30879916b9ca4f546f02b5dfed44e4bdf7320d898c
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Ali Alavi\nThe accurate calculation of the ground state 
 of many-electron systems has been the central goal of quantum chemistry fo
 r the last 80 years. Exact methods\, such as full CI\, can only be applied
  to systems of a few electrons and it has long been assumed [1] that large
 r fermionic systems will only be simulated exactly on powerful "quantum co
 mputers".\nHere we argue that this is not the case for a large class of re
 alistic electronic systems\, with up to ~50 electrons. The ground state of
  these fermion systems can be calculated using a very simple stochastic al
 gorithm [2\,3\,4]\, based on a population dynamics of a set of annihilatin
 g walkers of positive and negative sign in the space of the Slater determi
 nants of the system. We show that this algorithm can be used to solve diff
 icult fermion systems to unprecedented accuracy\, as exemplified by a rece
 nt application to the ionisation potential of the first row (3d) transitio
 n metal atoms [5]. Furthermore\, we show that a replica trick allows the u
 nbiased calculation of two-particle correlation functions [6]\, as well as
  excited states.\n[1] RP Feynman\, International J. of Theor. Phys.\, 21\,
  Nos. 6/7\, (1982).\n[2] GH Booth\, A Thom\, A Alavi\, J Chem Phys\,  131
  \, 054106\, (2009).\n[3] D Cleland\, GH Booth\, A Alavi\, J Chem Phys\, 1
 32 \, 041103\, (2010).\n[4] GH Booth\, A Grueneis\, G Kresse\, A Alavi\, N
 ature\, 493\, 365  (2013)\n[5] R Thomas\, GH Booth\, A Alavi\, Phys Rev L
 ett\,  114\, 033001  (2015)\n[6] C Overy\, GH Booth\, N Blunt\, JJ Sheph
 erd\, A Alavi\, J Chem Phys\, 141\, 244117\, (2014)
LOCATION:CO1 http://plan.epfl.ch/?room=CO%201
STATUS:CONFIRMED
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