Quantum computers made possible  calculation of quantum chemical 

Quantum computing and quantum information processing technology has attracted attention in recent emerging areas. In many important and fundamental issues in today's science, solving the Schroedinger Equation (SE) of atoms and molecules is one of the last goals in chemistry, physics and their related fields. SE is the "first principle" of non-relative quantum mechanics, whose solution can give information about electrons within the atoms and molecules to the wave functions, predict their physical properties and chemical reactions. 

Researchers at Osaka City University (OCU) in Japan, Dr. Sugisaki, Profs. K. Sato and T. Takui and colleagues have found a quantum algorithm that enables us to calculate complete configuration interactions (full-CI) for any open-shell molecules, without exponential / combustible explosion. The full-CI SE provides accurate numerical solutions, which are one of the intimate problems with any supercomputer. Implementation of such a quantum algorithm contributes to the acceleration of applying practical quantum computers.

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Paper Open Access Journal has been published on December 13, 2018, in the first issue of Chemical Physics Letters X.

He said, "As Derek claimed that the quantum mechanics was established in 1929, the exact application of mathematical principles to solve SE also makes equations equilibrium. In fact, the variables to be determined in full-CI The number increases rapidly against the size of the system, and it easily runs in astronomical data such as astronomical explosions. For example, the benzene molecule is flooded for C6H6. The dimension of C-CI calculation, which contains only 42 electrons, quantities up to 1044, which are impossible. Any supercomputer should be dealt with. "


According to the OCU research group, quantum computers can come back in 1982 on the suggestion of a Feynman that quantum mechanics can be added only by a computer made of quantum mechanical elements which comply with quantum mechanical rules. After more than 20 years, Asupuru-Guzick, Harvard University (Toronto Univ since 2018) and colleagues proposed a quantum algorithm which is not able to calculate the energies of atoms and molecules, but against the number of variables in the system polynomials, Quantum chemicals on quantum computers Creating a breakthrough in the field of science.

When Aspiru's quantum algorithm is applied to full-CI calculations on quantum computers, then the study requires close ripples of the exact waveforms of SE, otherwise, the repeated stages of repeat step Extreme steps are required to reach the exact people while obstructing the benefits of quantum computing. 

This problem is very serious for any open shell system, in which many unaffected electrons do not participate in the chemical bond. OCU researchers have dealt with this problem, one of the most interoperable issues in quantum science, and in 2016, in the polynomial computing time, the state functions of the configuration succeed in implementing quantum algorithms that generate special wave functions.

Already proposed algorithm requires a considerable number of quantum circuit gate operations proportionally proportional to the number of N, which shows the number of down-spines of unexpected electrons in the system. Thus, if N increases, total computing time does not increase rapidly but rather significantly. In addition, for the practical use of algorithm and quantum programming architecture, the complexity of the quantum circuit should be reduced. 

A new quantum algorithm exploits the germinal spin functions, which is called Serber construction, and reduces the number of gate operation to only 2n while executing parallelism of quantum gates. The OCU group said, "This is the first instance of the practical quantum algorithm, which enables quantum computers to be calculated on quantum computers, which are equipped with a large number of Quadrants. These implementations of Quantum computer's practical applications of quantum computers Empower in important areas. "