https://doi.org/10.1140/epjp/s13360-020-00374-z
Regular Article
Non-Hermitian coupled cluster method for non-stationary systems and its interaction-picture reinterpretation
1
Department of Physics and Astronomy, Schuster Building, The University of Manchester, Manchester, M13 9PL, UK
2
Quantum Systems Engineering Research Group, Department of Physics, Loughborough University, Leicestershire, LE11 3TU, UK
3
School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN, 55455, USA
4
The Czech Academy of Sciences, Nuclear Physics Institute, Hlavní 130, 250 68, Řež, Czech Republic
5
Department of Physics, Faculty of Science, University of Hradec Králové, Rokitanského 62, 500 03, Hradec Králové, Czech Republic
6
Institute of System Science, Durban University of Technology, P. O. Box 1334, Durban, 4000, South Africa
* e-mail: raymond.bishop@manchester.ac.uk
Received:
22
November
2019
Accepted:
1
April
2020
Published online:
27
April
2020
The interaction picture in a non-Hermitian realization is discussed in detail and considered for its practical use in many-body quantum physics. The resulting non-Hermitian interaction-picture (NHIP) description of dynamics, in which both the wave functions and operators belonging to physical observables cease to remain constant in time, is a non-Hermitian generalization of the traditional Dirac picture of standard quantum mechanics, which itself is widely used in quantum field theory calculations. Particular attention is paid here to the variational (or, better, bivariational) and dynamical (i.e., non-stationary) aspects that are characteristic of the coupled cluster method (CCM) techniques that nowadays form one of the most versatile and most accurate of all available formulations of quantum many-body theory. In so doing we expose and exploit multiple parallels between the NHIP and the CCM in its time-dependent versions.
© The Author(s), 2020
