Product Form of the Hamiltonian Operator

The solution of the MCTDH equations of motion requires the evaluation of the Hamiltonian and mean-fleld matrix elements. A Hamiltonian matrix element Kjj = 

a high dimensional integral is replaced by a sum of products of integrals of lower dimension that can be quickly evaluated. 

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The normal product form of the Hamiltonian operator is obtained by the use of the time-independent Wick theorem5-27 (also known as Wick s first theorem29) i.e.,... 

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