Reduced Scaling Real-Time Coupled Cluster Theory

• URL: http://arxiv.org/abs/2308.01664v1
• Date: Thu, 3 Aug 2023 10:08:47 GMT
• Title: Reduced Scaling Real-Time Coupled Cluster Theory
• Authors: Benjamin G. Peyton, Zhe Wang, and T. Daniel Crawford
• Abstract summary: We present the first application of local correlation to real-time CC. A detailed analysis of the dynamics suggests the main challenge is a strong time-dependence of the wave function.
• Score: 3.087140219508349
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Real-time coupled cluster (CC) methods have several advantages over their frequency-domain counterparts, namely, response and equation of motion CC theories. Broadband spectra, strong fields, and pulse manipulation allow for the simulation of complex spectroscopies which are unreachable using frequency-domain approaches. Due to the high-order polynomial scaling, the required numerical time-propagation of the CC residual expressions is a computationally demanding process. This scaling may be reduced by local correlation schemes, which aim to reduce the size of the (virtual) orbital space by truncating it according to user-defined parameters. We present the first application of local correlation to real-time CC. As in previous studies of locally correlated frequency-domain CC, traditional local correlation schemes are of limited utility for field-dependent properties; however, a perturbation-aware scheme proves promising. A detailed analysis of the amplitude dynamics suggests the main challenge is a strong time-dependence of the wave function sparsity.

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