Relativistic Two-Component Multireference Configuration Interaction Method with Tunable Correlation Space

Hu, Hang; Jenkins, Andrew J.; Liu, Hongbin; Kasper, Joseph M.; Frisch, Michael J.; Li, Xiaosong

doi:10.1021/acs.jctc.9b01290

Cited by 39 publications

(72 citation statements)

References 61 publications

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“…However, for systems with more than one unpaired electron, the linear response TDDFT is not able to capture all the microstates of a nearly degenerate ground state. One has to resort to variational, relativistic, multireference electronic structure theories. , …”

Section: Discussionmentioning

confidence: 99%

Relativistic Effects in Magnetic Circular Dichroism: Restricted Magnetic Balance and Temperature Dependence

Sun

2020

J. Chem. Theory Comput.

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Magnetic circular dichroism of transition metal complexes and open-shell systems are challenging to simulate and analyze, mainly due to the interplay of spin–orbit couplings and finite-magnetic-field induced Zeeman effects with the complex selection rules dictated by the circularly polarized light. In this work, we introduce an ab initio relativistic two-component formalism based on the restricted magnetic-balanced Hamiltonian for simulating MCD spectra. Both homogeneous finite magnetic field and relativistic effects are included variationally in the ground state reference. Finite-field London orbitals are used to enforce the constrained gauge-origin independence in the calculation using localized atomic orbitals. Through benchmark studies of AuCl4 –, Pt(CN)4 2–, and Mo(CN)8 3–, we discuss how relativistic effects are manifested in MCD for both closed-shell and open-shell molecular complexes and how the interplay between spin–orbit coupling and magnetic field modulates the MCD selection rules. Finally, an investigation on temperature-dependent MCD is carried out and compared to experiment.

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Section: Discussionmentioning

confidence: 99%

Relativistic Effects in Magnetic Circular Dichroism: Restricted Magnetic Balance and Temperature Dependence

Sun

2020

J. Chem. Theory Comput.

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“…Following the notation in Ref. 140 where we only consider singly occupied spin-orbitals that follow the Jordan-Wigner mapping.…”

Section: State Preparationmentioning

confidence: 99%

Simulating Effective QED on Quantum Computers

Stetina

Ciavarella

et al. 2022

Quantum

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In recent years simulations of chemistry and condensed materials has emerged as one of the preeminent applications of quantum computing, offering an exponential speedup for the solution of the electronic structure for certain strongly correlated electronic systems. To date, most treatments have ignored the question of whether relativistic effects, which are described most generally by quantum electrodynamics (QED), can also be simulated on a quantum computer in polynomial time. Here we show that effective QED, which is equivalent to QED to second order in perturbation theory, can be simulated in polynomial time under reasonable assumptions while properly treating all four components of the wavefunction of the fermionic field. In particular, we provide a detailed analysis of such simulations in position and momentum basis using Trotter-Suzuki formulas. We find that the number of T-gates needed to perform such simulations on a 3D lattice of ns sites scales at worst as O(ns3/ϵ)1+o(1) in the thermodynamic limit for position basis simulations and O(ns4+2/3/ϵ)1+o(1) in momentum basis. We also find that qubitization scales slightly better with a worst case scaling of O~(ns2+2/3/ϵ) for lattice eQED and complications in the prepare circuit leads to a slightly worse scaling in momentum basis of O~(ns5+2/3/ϵ). We further provide concrete gate counts for simulating a relativistic version of the uniform electron gas that show challenging problems can be simulated using fewer than 1013 non-Clifford operations and also provide a detailed discussion of how to prepare multi-reference configuration interaction states in effective QED which can provide a reasonable initial guess for the ground state. Finally, we estimate the planewave cutoffs needed to accurately simulate heavy elements such as gold.

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“…Following the notation in Ref. 64 where we only consider singly occupied spin-orbitals that follow the Jordan-Wigner mapping.…”

Section: B Cost Estimate For Qpementioning

confidence: 99%

Simulating Effective QED on Quantum Computers

Stetina,

Ciavarella,

et al. 2021

Preprint

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In recent years simulations of chemistry and condensed materials has emerged as one of the preeminent applications of quantum computing offering an exponential speedup for the solution of the electronic structure for certain strongly correlated electronic systems. To date, most treatments have ignored the question of whether relativistic effects, which are described most generally by quantum electrodynamics (QED), can also be simulated on a quantum computer in polynomial time. Here we show that effective QED, which is equivalent to QED to second order in perturbation theory, can be simulated in polynomial time under reasonable assumptions while properly treating all four components of the wavefunction of the fermionic field. In particular, we provide a detailed analysis of such simulations in position and momentum basis using Trotter-Suzuki formulas. We find that the number of T -gates needed to perform such simulations on a 3D lattice of ns sites scales at worst as O(n 3 s / ) 1+o(1) in the thermodynamic limit for position basis simulations and O(n 1) in momentum basis. We also find that qubitization scales slightly better with a worst case scaling of O(n 2+2/3 s / ) for lattice eQED and complications in the prepare circuit leads to a slightly worse scaling in momentum basis of O(n 5+2/3 s / ). We further provide concrete gate counts for simulating a relativistic version of the uniform electron gas that show challenging problems can be simulated using fewer than 10 13 non-Clifford operations and also provide a detailed discussion of how to prepare MRCISD states in effective QED which provide a reasonable initial guess for the groundstate. Finally, we estimate the planewave cutoffs needed to accurately simulate heavy elements such as gold.

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Relativistic Two-Component Multireference Configuration Interaction Method with Tunable Correlation Space

Cited by 39 publications

References 61 publications

Relativistic Effects in Magnetic Circular Dichroism: Restricted Magnetic Balance and Temperature Dependence

Relativistic Effects in Magnetic Circular Dichroism: Restricted Magnetic Balance and Temperature Dependence

Simulating Effective QED on Quantum Computers

Simulating Effective QED on Quantum Computers

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