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Workshops

Expeditious Methods in Electronic Structure Theory and Many Body Techniques

December 17, 2017 to December 20, 2017
Location : CECAM-ISR

Organisers

  • Roi Baer (Hebrew University of Jerusalem, Israel)
  • Eran Rabani (Tel Aviv University and University of California, Berkeley, Israel)

Supports

   CECAM

Hebrew University (Fritz Haber Center)

Description

Electronic structure involves a basic science study of the electronic excitations in molecular and nanostructured systems with significant technological implications. The role of theory in this field is to predict properties of materials as well as nanostructured and supramolecular systems. Hence the main challenges facing electronic structure theory are: predictive power and applicability for large systems. Predictivity implies the development of first-principles high-level treatments of electron correlations while tackling large systems requires low computational complexity. Progress is slow since these two requirements are mutually exclusive: high-level theories of electron correlation involve high computational complexity.[Whitfield2013]

In the past two decades approaches for low-scaling ab initio methods, based on density functional theory and perturbation theory, have been developed with varying degree of generality and success.[Goedecker1999, Gillan2007, Beer2008] However, unlike the quantum Monte Carlo methods for quantum chemistry, stochastic methods for electronic structure have not yet found a central role in the field. This situation is now changing as a surge of new ideas concerning stochastic quantum processes is observed. The proposed workshop is intended to bring together researchers that are developing new stochastic methods or low scaling high precision methods for electronic structure of large systems. The basic hope is that such a workshop can synergistically inspire researchers to develop new ideas and paradigms which can be used

Stochastic methods involve, necessarily, a stochastic process that allows efficient sampling of the configurational space from which the computed quantity can be estimated. The best known methods, such as variational, diffusion and Green's function Monte Carlo have already proved strengths and (unavoidably) weaknesses.[#Nightingale1999, #Hammond1994, #Gubernatis2016] Many workshops and schools on QMC methods are held annually and it is not our goal to entertain an additional meeting on this topic. Instead we aim at stochastic methods for the community developing techniques for accelerating the calculation of approximate (but highly accurate) electron correlation theories.

Such stochastic methods concerning electron correlation have recently been published, such as the stochastic CI [#Booth2009, #Ten-no2013, #Thomas2015], stochastic DFT,[#Baer2013, #Neuhauser2015], coupled-cluster and perturbation theory [#Thom2010, #Thom2007a, #Willow2012, #Neuhauser2013], random phase approximation,[#Neuhauser2013a] GW theory[#Neuhauser2014], response and Bethe-Salpeter equation,[#Neuscamman2013, #Rabani2015], theory of multiexciton generation rates in nanocrystals.[#Baer2012a] and continuous time Monte Carlo for nonequilibrium quantum impurity problems.[#Muehlbacher2008, #Gull2011, #Cohen2015]

The aim of the proposed workshop is to bring together the leading scientists representing low complexity and/or stochastic approaches for large scale electronic structure calculations. Unlike workshops on Quantum Monte Carlo methods focusing on the solution of the many-body Schrödinger equation, the proposed workshop targets stochastic approaches to high complexity single- or two-particle methods such as 1) for ground states: density functional and Hartree-Fock (DFT and HFT) theory, perturbative methods (Random Phase Approximation (RPA), Moller-Plesset Theory MPn, coupled cluster (CC) approaches), geminal electronic structure and 2) for excitations response and dynamics: many-body perturbation theory (GW, Bethe-Salpeter GF2, time-dependent DFT (TDDFT) etc.) and continuous time Monet Carlo.

The idea behind the proposed workshop is to bring together experts developing a wide range of tools to solve the quantum many-body problem. The unifying theme is the stochastic nature of the algorithms underlying the approaches developed by the invited speakers. The workshop will include experts that rarely meet and discuss science. This unique environment will provide scientists additional tools to expand into novel directions by adopting approaches from other fields. All invited speakers are leaders in the field of the quantum many-body problem and have contributed to the development of methods and applications in one of the fields, i.e. density function theory and its time dependent version, perturbative electronic structure methods, many-body perturbation techniques, and many-body diagrammatic methods. The diverse background of speaker’s expertise in method development and applications is expected to lead to synergetic collaborations of researchers from different disciplines, all working on the quantum many-body problem..


For more information and Registrationstochastic-methods-in-electronic-structure-theory

References

[Whitfield2013] James Daniel Whitfield, Peter John Love, and Alan Aspuru-Guzik. Computational complexity in electronic structure. Physical Chemistry Chemical Physics, 15(2):397{411, 2013.
[Goedecker1999] S. Goedecker. Linear scaling electronic structure methods. Rev. Mod. Phys., 71(4):1085-1123, 1999.
[Gillan2007] M. J. Gillan, D. R. Bowler, A. S. Torralba, and T. Miyazaki. Order-n first-principles calculations with the conquest code. Comput. Phys. Commun., 177(1-2):14{18, 2007.
[Beer2008] M. Beer and C. Ochsenfeld. Ecient linear-scaling calculation of response properties: Density matrix-based Laplace-transformed coupled-perturbed self-consistent eld theory. J. Chem. Phys., 128(22):221102, 2008.
[Nightingale1999] M. P. Nightingale and C. J. Umrigar. Quantum Monte Carlo methods in physics and chemistry,volume 525 of NATO Science Series C: Mathematical and Physical Sciences. Kluwer Academic Publishers, The Netherlands, 1999.
[Hammond1994] B.L. Hammond, W.A. Lester Jr., and P.J. Reynolds. Monte Carlo Methods in ab initio quantum chemistry. World Scienti c, Singapore, 1994.
[Gubernatis2016] James Gubernatis, Naoki Kawashima, and Philipp Werner. Quantum Monte Carlo Methods. Cambridge University Press, 2016.
[Booth2009] George H Booth, Alex JW Thom, and Ali Alavi. Fermion monte carlo without xed nodes: A game of life, death, and annihilation in slater determinant space. J. Chem. Phys., 131:054106, 2009.
[Ten-no2013] Seiichiro Ten-no. Stochastic determination of e ective hamiltonian for the full con guration interaction solution of quasi-degenerate electronic states. The Journal of chemical physics, 138(16):164126, 2013.
[Thomas2015] Robert E Thomas, Qiming Sun, Ali Alavi, and George H Booth. Stochastic multiconfigurational self-consistent eld theory. Journal of chemical theory and computation, 11(11):5316-5325, 2015.
[Baer2013] Roi Baer, Daniel Neuhauser, and Eran Rabani. Self-averaging stochastic kohn-sham density functional theory. Phys. Rev. Lett., 111:106402, Sep 2013.
[Neuhauser2015] Daniel Neuhauser, Eran Rabani, Yael Cytter, and Roi Baer. Stochastic optimally tuned range-separated hybrid density functional theory. The Journal of Physical Chemistry A,120(19):3071{3078, 2015.
[Thom2010] Alex JW Thom. Stochastic coupled cluster theory. Physical review letters, 105(26):263004, 2010.
[Thom2007a] Alex JW Thom and Ali Alavi. Stochastic perturbation theory: A low-scaling approach to correlated electronic energies. Phys. Rev. Lett., 99(14):143001, 2007.
[Willow2012] S. Y. Willow, K. S. Kim, and S. Hirata. Stochastic evaluation of second-order many-body
perturbation energies. J. Chem. Phys., 137(20):204122, 2012.
[Neuhauser2013] Daniel Neuhauser, Eran Rabani, and Roi Baer. Expeditious stochastic approach for mp2 correlation energies in large electronic systems. J. Chem. Theory Comput., 9(1):24{27, 2013.
[Neuhauser2013a] Daniel Neuhauser, Eran Rabani, and Roi Baer. Expeditious stochastic calculation of randomphase approximation energies for thousands of electrons in three dimensions. J. Phys. Chem. Lett., 4(7):1172{1176, 2013.
[Neuhauser2014] Daniel Neuhauser, Yi Gao, Christopher Arntsen, Cyrus Karshenas, Eran Rabani, and Roi Baer. Breaking the theoretical scaling limit for predicting quasiparticle energies: The stochastic gw approach. Phys. Rev. Lett., 113(7):076402, 2014.
[Neuscamman2013] Eric Neuscamman. Communication: A jastrow factor coupled cluster theory for weak and
strong electron correlation. The Journal of chemical physics, 139(18):181101, 2013.
[Rabani2015] Eran Rabani, Roi Baer, and Daniel Neuhauser. Time-dependent stochastic bethe-salpeter
approach. Physical Review B, 91(23):235302, 2015.
[Baer2012a] R. Baer and E. Rabani. Expeditious stochastic calculation of multiexciton generation rates in
semiconductor nanocrystals. Nano Lett., 12:2123, 2012.
[Muehlbacher2008] Lothar Muhlbacher and Eran Rabani. Real-time path integral approach to nonequilibrium
many-body quantum systems. Physical review letters, 100(17):176403, 2008.
[Gull2011] Emanuel Gull, Andrew J Millis, Alexander I Lichtenstein, Alexey N Rubtsov, Matthias Troyer,
and Philipp Werner. Continuous-time monte carlo methods for quantum impurity models.
Reviews of Modern Physics, 83(2):349, 2011.
[Cohen2015] Guy Cohen, Emanuel Gull, David R Reichman, and Andrew J Millis. Taming the dynamical
sign problem in real-time evolution of quantum many-body problems. Phys. Rev. Lett.,
115(26):266802, 2015.