Scaling of the one-norm and number of unique, non-zero coefficients (NNZ) for test systems.

First-Quantization: A Quantum Leap for Molecular Energy Solvers

Researchers have developed a novel first-quantization method for quantum computing that achieves significant improvements in efficiency for molecular energy calculations across arbitrary basis sets, demonstrating both asymptotic speedup in molecular orbital calculations and orders-of-magnitude resource reductions when using dual plane waves compared to second-quantization approaches.

Binding potential energy curve for molecular nitrogen, N2.

Contextual VQE: N₂ Bond Breaking on Superconducting Qubits

This research demonstrates a Contextual Subspace Variational Quantum Eigensolver on superconducting hardware that successfully models N₂ molecular bond-breaking with superior accuracy to single-reference wavefunction techniques, achieved through comprehensive error mitigation strategies and circuit optimization while requiring fewer quantum resources than comparable classical approaches.

Results of geometry optimizations for H2 molecule. Geometry optimizations with various initial values of the H–H interatomic distance revealed that the calculation quickly converges to the equilibrium bond length within 10 iterations, no matter which interatomic distance is used to start the calculation.

Quantum algorithm of the direct calculation of energy derivatives developed for molecular geometry optimization

Researchers have successfully extended the quantum phase difference estimation algorithm, a general quantum algorithm for the direct calculations of energy gaps, to enable the direct calculation of energy differences between two different molecular geometries. This allows for the computation, based on the finite difference method, of energy derivatives with respect to nuclear coordinates in a single calculation.

Quantum algorithms save time in the calculation of electron dynamics

Quantum Algorithms Break Ground in Molecular Computation

Quantum computers promise significantly shorter computing times for complex problems. But there are still only a few quantum computers worldwide with a limited number of so-called qubits. However, quantum computer algorithms can already run on conventional servers that simulate a quantum computer. A team has succeeded in calculating the electron orbitals and their dynamic development using an example of a small molecule after a laser pulse excitation.

Iron–sulfur clusters used in the present work, and their active spaces (specified by numbers of active electrons and orbitals).

Low rank representations for quantum simulation of electronic structure

The quantum simulation of quantum chemistry shows promise with a novel two-step low-rank factorization method that substantially reduces gate complexity of Hamiltonian and unitary Coupled Cluster Trotter steps, enabling practical implementation on near-term quantum devices with linear connectivity, as demonstrated by a 50-qubit molecular simulation requiring only 4,000 layers of two-qubit gates.