Mizuki Uenomachi

Development of non-invasive quantum diagnostic technology via nuclear spin

Grant No.：JPMJPR23F1

Researcher : Mizuki Uenomachi

Outline

There is no technology that can simultaneously detect microenvironmental information and its position deep within the body. In this study, I will develop a novel non-invasive quantum diagnostic technology that utilizes the nuclear spin of cascade nuclides emitting multiple photons successively as a “quantum sensor” to simultaneously obtain microenvironmental information and radioactive drug accumulation. This study aims to establish the world’s first imaging technology that extracts information on electromagnetic fields, temperature, pH, etc. deep within the body by performing principle and experimental verifications for medical applications, and physically elucidating photon correlations.

Kazuhisa Ogawa

Large-scale superconducting quantum computing using the standing ZZ interaction

Grant No.：JPMJPR23F2

Researcher : Kazuhisa Ogawa

Outline

The scalability problem is becoming more and more serious as quantum computers are scaled up. In this study, we propose a new scheme that uses the standing ZZ interaction as a two-qubit gate, and theoretically and experimentally verify the effectiveness of the proposed scheme against the three problems of excessive number of control lines, frequency collision, and burden on microwave control devices.

Takuya Okuda

Approaches to the simulation of lattice gauge theories based on quantum information theory

Grant No.：JPMJPR23F3

Researcher : Takuya Okuda

Outline

The aim of this research is to develop efficient algorithms to simulate lattice gauge theories, improve precision, and make it possible to analyze the problems that have been intractable. I will advance the theories of circuit-based as well as measurement-based quantum simulation methods, propose new algorithms, and implement them on real quantum computers. I will also develop new algorithms for the simulation of lattice gauge theories in the Hamiltonian formalism through efforts to perform classical simulations using tensor network techniques.

Hiroki Kutsuma

Development of photon-number-resolving scalable single photon detectors

Grant No.：JPMJPR23F4

Researcher : Hiroki Kutsuma

Outline

The project goal is to create photon-number-resolving scalable single photon detectors for optical quantum computers with knowledge from different fields such as superconducting, microwave circuits, photon detectors, and amplifiers. Here, I will demonstrate photon-number-resolving microwire detectors connected to superconducting parametric amplifiers.

Tetsushi Takano

Integration of cold-atom devices with waveguides

Grant No.：JPMJPR23F5

Researcher : Tetsushi Takano

Outline

I will trap neutral thulium atoms by the evanescent light of the standing waves which propagate an optical waveguide. Thulium atoms have a clock transition, which is extremely insensitive to an electric field (for example, about 1/4000 of strontium atoms) since fully occupied outer shells of thulium atoms act as an electrostatic shield. This feature will make thulium atoms robust against decoherence even near the waveguide surface. Furthermore, by controlling the disturbance due to the evanescent light using the magic wavelength method, the optical coherence of the thulium atoms is expected to be more than ms. This device is considered to be suitable for the platform of the quantum communications.

Nayuta Takemori

Quantum new testbeds for quasiperiodic systems by k-RDM estimation quantum algorithm

Grant No.：JPMJPR23F6

Researcher : Nayuta Takemori

Outline

We present the development of a quantum subspace expansion method using kth-order reduced density matrix (RDMs) estimation via the Fermionic shadow. Leveraging the Fermionic shadow streamlines the evaluation of k-RDMs, and when combined with techniques for approximating higher-order RDMs with lower-order ones, it significantly reduces the computational cost required for quantum subspace expansion. As a testbed for demonstrating the quantum advantage necessitating RDMs, we focus on quasiperiodic systems. This novel approach not only contributes to the advancement of quantum algorithms for obtaining k-RDMs but also showcases their applicability in the exploration of quantum novelty in quasiperiodic systems.

Tatsumi Nitta

Co-creation of superconducting sensors and dark matter searches

Grant No.：JPMJPR23F7

Researcher : Tatsumi Nitta

Outline

Superconducting qubits which are one of the key elements for quantum computing can be utilized as a single photon sensor. I develop a specific type of superconducting qubits for realizing the frequency tunability of the photon sensor which is never realized. Furthermore, I apply this sensor to dark matter searches and realize wideband dark matter searches.

Akito Noiri

Development of a scalable unit cell of a silicon quantum computer

Grant No.：JPMJPR23F8

Researcher : Akito Noiri

Outline

The target of this project is to develop a scalable unit cell structure of a silicon quantum computer based on a coherent shuttling of a qubit between quantum dots. A relationship between a shuttling performance and a shuttling distance will be elucidated. With this insight, a unit cell structure which solves a dense wiring problem, a major challenge of a scaling up, will be designed. The proposed unit cell can maintain a demonstrated high performance of qubit operations in a scaling up.

Ryu Hayakawa

Quantum topological machine learning and its computational complexity

Grant No.：JPMJPR23F9

Researcher : Ryu Hayakawa

Outline

Topological data analysis has been gathering attention as an application of quantum computing with potential significant speedup over the classical counterparts. In this project, I will construct a quantum machine learning algorithm that is based on quantum topological data analysis. Moreover, I will study the computational complexity of the homology problems, especially, the relationships with Hamiltonian complexity. Through the analysis of the computational complexity of the homology problems, I will also try to establish the theoretical foundation for the quantum advantage in the task of topological machine learning.

Kosuke Fukui

Hybrid quantum networks with fault-tolerant light-matter interconnects

Grant No.：JPMJPR23FA

Researcher : Kosuke Fukui

Outline

Towards large-scale quantum information processing, we propose a scheme to realize fault-tolerant quantum network through the integration of complementary quantum architectures encompassing optical and matter qubits. We develop a methodology for constructing quantum networks via quantum error-correcting codes with light, alongside a technique for realizing noise-tolerant light through light-matter interactions. This project will establish a theoretical platform for a quantum network that fully harnesses both optical and matter qubits.

Tomohiro Fukushima

Modification of electrochemical energy conversion based on the strong coupling phenomena

Grant No.：JPMJPR23FB

Researcher : Tomohiro Fukushima

Outline

This research project aims to innovate electrochemical energy conversion science through strong coupling. Controllable vacuum field can be designed by focusing on localization and strength of vacuum electric field. Based on the control of water properties, ionic conduction and electrocatalytic property modulation will be evaluated spectroelectrochemically to clarify the contribution of the coupling strength to the change in properties. Furthermore, by investigating the strong coupling effects of heat and work, I will elucidate the basic science and pioneer applications to energy conversion.

Hayata Yamasaki

Theoretical foundation of time-efficient constant-space-overhead fault-tolerant quantum computation

Grant No.：JPMJPR23FC

Researcher : Hayata Yamasaki

Outline

This research aims to advance the theory of good quantum low-density parity-check codes based on high-dimensional expanders and employ these codes to establish fault-tolerant protocols achieving low space and time overheads. Furthermore, toward its implementation in an optical platform, the research aims to develop quantum resource theories and classical numerical simulation methods to support resource estimation. The expected results of this research establish a comprehensive theoretical foundation for realizing time-efficient constant-space-overhead fault-tolerant quantum computation.