Project/Area Number 
19F19028

Research Category 
GrantinAid for JSPS Fellows

Allocation Type  Singleyear Grants 
Section  外国 
Review Section 
Basic Section 13010:Mathematical physics and fundamental theory of condensed matter physicsrelated

Research Institution  Institute of Physical and Chemical Research 
Host Researcher 
NORI FRANCO 国立研究開発法人理化学研究所, 開拓研究本部, 主任研究員 (50415262)

Foreign Research Fellow 
CHEN YEHONG 国立研究開発法人理化学研究所, 開拓研究本部, 外国人特別研究員

Project Period (FY) 
20191011 – 20220331

Project Status 
Granted (Fiscal Year 2020)

Budget Amount *help 
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2021: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2020: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2019: ¥700,000 (Direct Cost: ¥700,000)

Keywords  Ultrastrong systems / Shortcuts to / adiabaticity / Rapid dynamical / evolution 
Outline of Research at the Start 
(1)Developingaccelerated dynamics for open systems. For an open quantum system modeled by the LindbladMarkovian master equation, we plan to develop two ways to accelerate the dynamics: an analytical one and a nonanalytic one. (2)Applyingaccelerated dynamics tooptomechanical systems. We plan to study howto develop accelerated dynamics for optomechanical cavity systemswithmembranes. (3)Applyingaccelerated dynamics tospin chain systems. We plan to accelerate some quantum adiabatic processes based on spin chain systems.

Outline of Annual Research Achievements 
Since Sep. 2019, we focused on the following two topics: (1). The ground state of a ultrastrong coupling system involves an appreciable number of virtual cavity photons. We investigated the possibility of using shortcuts to adiabaticity (STA) to rapidly convert these virtual photons into real ones. The photons, with the energy from the driving fields, are produced by the counterrotating effects of the lightmatter coupling. By modifying the shape of the driving fields, we construct shortcuts to attain the target state, so that the evolution can be 5 times faster than that via adiabatic passages. Such a faster evolution can benefit to the robustness against photon loss. (2). The ground state of the quantum Rabi model consists of photonic Schrodinger's cat states entangled with the atom and exhibits nonclassical properties such as squeezing. This provides a possibility to generate nonclassical. We studied the possibility of using STA to modify the parameters for a simulated quantum Rabi model to rapidly generate nonclassical states. By applying the counterdiabatic driving, the time required to reach the target state is 100 times shorter than that via adiabatic passage. Therefore, our accelerated scheme is much more robust against dissipations.

Current Status of Research Progress 
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
We have almost finished the mathematics and the numerical simulations for the theoretical schemes. And we have started written manuscripts according to the results we have obtained. The papers will be soon summited to appropriate journals for peer review.

Strategy for Future Research Activity 
In the following months, we will complete the current work and summit the papers. Then, we are going to do more research in the ultrastrong coupling systems. And we will discuss how to use accelerated quantum control methods in controlling a ultrastrong coupling system (or a simulated ultrastrong coupling system) to realize quantum information processing. For instance, we will investigate the possibility of applying Shortcuts to adiabaticity in ultrastrong coupling system to realize quantum gates and quantum computing.
