Related Experiment Video
Updated: Apr 23, 2026

Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Communication: A flexible multi-reference perturbation theory by minimizing the Hylleraas functional with matrix
Sandeep Sharma1, Garnet Kin-Lic Chan1
1Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, USA.
Abstract:
We describe a formulation of multi-reference perturbation theory that obtains a rigorous upper bound to the second order energy by minimizing the Hylleraas functional in the space of matrix product states (MPS). The first order wavefunctions so obtained can also be used to compute the third order energy with little overhead. Our formulation has several advantages including (i) flexibility with respect to the choice of zeroth order Hamiltonian, (ii) recovery of the exact uncontracted multi-reference perturbation theory energies in the limit of large MPS bond dimension, (iii) no requirement to compute high body density matrices, (iv) an embarrassingly parallel algorithm (scaling up to the number of virtual orbitals, squared, processors). Preliminary numerical examples show that the MPS bond dimension required for accurate first order wavefunctions scales sub-linearly with the size of the basis.
More Related Videos
Related Concept Videos
Multi-input and Multi-variable systems
In the absence of...
State Space Representation
Consider an RLC circuit, a...
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Linear Approximation in Time Domain
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length,...
Double Resonance Techniques: Overview
Spin decoupling is usually achieved by...
Transfer Function to State Space
In an...

