Title: Modeling versus realistic first principles calculations/simulations in condensed matter theory(*)
Speaker: Erio Tosatti （SISSA的创始人之一、意大利国际理论物理中心前主任、美国科学院院士）
International Centre for Theoretical Physics (ICTP)
International School for Advanced Studies (SISSA)
Time: 3:00pm-5:00pm., 2016.12.8
Location: Physics Building, Room 216
Abstract: A split between different approaches and philosophies historically divides the condensed matter theory and materials simulation community,roughly speaking, into two.
One approach is based on models -- idealized simple hamiltonians that can be solved to describe the essence of phenomena, many of which of strong current interest. A small subset might include Hubbard models, Anderson models, Kondo effects, Frenkel-Kontorova model, etc. These famous models describe the essence of deep physical phenomena, but are based on parameters that are generally unknown and must be determined empirically.
The other approach is based on realistic, first principles electronic structure calculations and/or quantitative simulations. In principle less dependent of arbitrary parameters, these calculations attempt at addressing the real systems in their much greater complexity. To achieve that goal however, they must generally restrict to mean-field approximations such as local density functional theory, whose nature is often incompatible with the many-body physics that must be described, or else they must ignore quantum effects altogether.
While both approaches and philosophies are essential, either of them alone is incomplete, and efforts to join them are under way on many fronts. I will use some examples developed within our group, to illustrate modest but revealing attempts at joining together realistic calculations and model approaches. Depending on available time, my examples will include the Mott and superconducting states of Cs3C60, [1] the zero-bias STS Kondo conductance anomaly of NO/Au(111),[2] and the frictional sliding of colloidal monolayers.[3]
(*) Partly supported by EU contract ERC No. 320796 MODPHYSFRICT
[1] M. Capone, M, Fabrizio, C. Castellani, E. Tosatti, , Rev. Mod. Phys. 81, 943 (2009); S. Naghavi, M. Fabrizio, T. Qin, E. Tosatti, Nanoscale 8 , 17483 (2016).
[2] P. Lucignano, R. Mazzarello, A. Smogunov, M. Fabrizio, E. Tosatti, Nature Materials 8, 563 (2009); R. Requist,. S. Modesti, P. P. Baruselli, A. Smogunov,
M. Fabrizio and E. Tosatti, PNAS 111, 69 (2014); R. Requist et al., Nature Nanotechnology 11, 499 (2016).
[3] A. Vanossi, N. Manini, E. Tosatti, PNAS 109, 16429 (2012); 109, 20774 (2012) (corr.); A. Vanossi, N. Manini, M. Urbakh, S. Zapperi, and E. Tosatti,
Rev. Mod. Phys 85, 529 (2013); D. Mandelli et al., Phys. Rev. Letters 114, 108302 (2015); S. Paronuzzi et al., J. Phys. Cond. Matter 28 ,134006 (2016).
