Seiseki Akibue

Optimization and verification of distributed quantum operations for multipartite secure quantum communication protocols

Grant No.：JPMJPR2111

Researcher

Seiseki Akibue

Outline

To implement multipartite secure quantum communication protocols such as the quantum secret sharing and the multipartite quantum communication, which are expected as next-generation quantum information processing technologies as well as a foundation of the large-scale distributed quantum computation, it is desirable to optimize distributed quantum operations and quantum entanglement between communication nodes. In this research, I establish versatile methods for optimizing the distributed quantum operations and for verifying and minimizing the sharing cost of quantum entanglement taking advantage of the characteristics of the protocols, which would be theoretical foundations for the implementation of various multipartite secure quantum communication protocols.

Tatsuhiko N. Ikeda

Quantum simulation of many-body wave functions in condensed-matter problems

Grant No.：JPMJPR2112

Researcher

Tatsuhiko N. Ikeda

Outline

Wavefunctions of quantum many-body systems originally contain various information that determines their physical properties, but it is very difficult for classical computers to calculate all of them. In this project, I will construct a technical basis for analyzing the wavefunction of a quantum many-body system using a commercial quantum computer and a GPU simulator. I also aim to use this technology to solve unsolved problems in condensed matter physics and quantum statistical physics.

Etsuko Itou

Development of classical and quantum computation methods for field theories with sign problems

Grant No.：JPMJPR2113

Researcher

Etsuko Itou

Outline

I will develop quantum computation algorithms for simulating field theories that describe the physics of elementary particles. I will implement several classical-quantum hybrid calculation methods and verify which method is effective. I will also apply these methods to clarify the properties of systems with the sign problem, which are difficult to simulate with conventional Monte Carlo method. The basic codes will open to the public and will be useful for particle and nuclear theoriests.

Suguru Endo

Development of Fundamental theory and Proposal of highly pracatical methods for Quantum Error Mitigation

Grant No.：JPMJPR2114

Researcher

Suguru Endo

Outline

Recently, quantum error mitigation, a technique for compensating for computational errors in quantum computers, has been actively studied. In this research, I give a unified definition to the various quantum error mitigation techniques that have been discovered. Then, by combining the quantum error mitigation techniques, I propose a highly practical quantum error mitigation technique that is efficient and can cope with complicated noise. I also study an efficient fault-tolerant quantum computing architecture that incorporates quantum error mitigation.

Tatsuhiko Ohto

Development of a multi-level interface program connecting first-principles methods with quantum algorithms

Grant No.：JPMJPR2115

Researcher

Tatsuhiko Ohto

Outline

We develop an interface program connecting density funcitonal theory with quantum eigen solver to apply quantum algorithms to realistic and large systems such as a solute molecule in water and a molecule adsorbing on surfaces. To include the effects of the environment, we construct an effective Hamiltonian for the variational quantum eigensolver using embedded potentials. In addition to the calculations of energies, we also perform first-principles molecular dynamics simulations using the variational quantum eigensolver and compute physical quantities at the coupled-cluster level.

Tomotaka Kuwahara

Exponential speedup in quantum computing based on quantum many-body theory

Grant No.：JPMJPR2116

Researcher

Tomotaka Kuwahara

Outline

A research field called Hamiltonian complexity is currently developing e the computational complexity of quantum many-body systems. Hamiltonian complexity has attracted a great deal of attention for the proof of quantum supremacy and the development of quantum algorithms with efficiency guarantees. This research field is an interdisciplinary research area between computer science and physics, where various unsolved problems are defined in a mathematically precise way. My research aim is to solve these mathematically unsolved problems.

Masazumi Honda

Development of quantum algorithms for early universe

Grant No.：JPMJPR2117

Researcher

Masazumi Honda

Outline

At the beginning of the universe, what was really going on? To answer this question, we need to understand the physical law governing the early universe and study its time evolution. This task is known to require a huge computational cost if we use conventional technology. In this research, I aim to develop and establish quantum algorithms to overcome this situation by quantum computation.

Daisuke Yamamoto

Development of quantum state reconstruction method and quantum entanglement detection for artificial quantum systems

Grant No.：JPMJPR2118

Researcher

Daisuke Yamamoto

Outline

Detecting the quantum state of artificial quantum systems and the quantum entanglement existing in it is a key issue for quantum computing and simulations. This project aims to develop quantum state reconstruction method and quantum entanglement detection with an efficient algorithm at a realistic cost, assuming ultracold atoms trapped in an optical lattice as an example of artificial quantum systems. After the implementation tests on the cold atom quantum simulators, the constructed method will be intended to be applied to other artificial quantum systems.

Nobuyuki Yoshioka

Establishing Quantum Parallel Computing Infrastructure

Grant No.：JPMJPR2119

Researcher

Nobuyuki Yoshioka

Outline

Drastic advancements in quantum information technology are bringing us closer to an era in which large-scale quantum computing is within reach. However, we have not fully explored the techniques to make the most of quantum resources without fault tolerance. In this project, we aim to establish a theoretical framework that pushes the boundaries of feasible high-precision operations, relying on a novel notion of “quantum parallel circuits.” We explore how to enhance the computational capacity by controlling quantum correlations between independently executed quantum circuits and classical post-processing technologies.

Shohei Watabe

Deveoplment of Imaginary Time Quantum Toolbox

Grant No.：JPMJPR211A

Researcher

Shohei Watabe

Outline

Obtaining the solution of combinatorial optimization problems is an important current issue for sustainable society. Quantum annealing is a unique method to solve this problem by using quantum effects, although it is also known to have issues and is currently being studied extensively and intensively. In my research project, we develop a method of realizing a quantum computer for imaginary-time quantum annealing as a new solver for combinatorial optimization problems. We will further develop efficiency improvement methods and develop the Imaginary Time Quantum Toolbox, which incorporates these methods.