The Journal of Physical Chemistry Letters

Using a quantum computer, Osaka Metropolitan University researchers utilized quantum logic circuits to directly calculate, in a single calculation, the energy difference between two molecular geometries. The developed method was then applied to execute the molecular geometry optimization of typical molecular systems. On a classical computer, calculations based on the finite difference method require at least two evaluations of the energy for one-dimensional systems, but previous research has shown that a quantum computer can be used to calculate the energy derivatives based on this method in a single calculation. However, quantum circuits relevant to quantum algorithms capable of performing the energy derivative calculations had not been implemented. The research group has successfully created a quantum circuit to calculate the energy derivatives by modifying the quantum circuit used in the previously developed quantum phase difference estimation algorithm.

In a continuing effort to improve upon previous work, a research team at the Graduate School of Science, Osaka City University, have applied their recently developed Bayesian phase difference estimation quantum algorithm to perform full configuration interaction (full-CI) calculations of atoms and molecules without simulating the time evolution of the wave function conditional on an ancillary qubit. Superior to conventional methods in terms of parallel execution of quantum gates during quantum computing, this new algorithm is expected to be much easier to implement in actual quantum computers.

A two-dimensional map of proteins, including secondary structures, was obtained for the hindwings of an insect (Anomala albopilosa) at the spatial resolution of 100 µm. Mapping was achieved with the microscopic vibrational circular dichroism (VCD) system, which has been developed in our laboratory. As a result, the insect hindwing was revealed to be composed of segregated microdomains consisting of proteins with different secondary structures.

Researchers improve their newly established quantum algorithm, bringing it to one-tenth the computational cost of Quantum Phase Estimation, and use it to directly calculate the vertical ionization energies of light atoms and molecules such as CO, O2, CN, F2, H2O, NH3 within 0.1 electron volts of precision.

Hokkaido University scientists show that under laboratory conditions, ultraviolet light reacts with nitrophenol to produce smog-generating nitrous acid.

Scientists at The University of Tokyo study aluminosilicate glass to determine its complex local structure with unprecedented detail. This work may lead to tougher and more inexpensive glass for touchscreens and solar arrays