Exploring the effect of correlations on quantum speed limits in interacting cold atom systems
| Project/Area Number |
21K13856
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 13010:Mathematical physics and fundamental theory of condensed matter physics-related
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| Research Institution | Okinawa Institute of Science and Technology Graduate University |
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Principal Investigator |
FOGARTY Thomas 沖縄科学技術大学院大学, 量子システム研究ユニット, スタッフサイエンティスト (60786987)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Granted (Fiscal Year 2022)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Fiscal Year 2022: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | quantum speed limits / orthogonality / interacting states / quantum control / quantum correlations / supersymmetry / quantum entanglement |
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| Outline of Research at the Start |
The goal of my project will be to explore the effect of finite interactions on the dynamics of a few-particle cold atom system and if their inherent correlations can increase the speed of evolution. To achieve this I plan to examine the QSL in various correlation regimes using both controlled and quench dynamics. While many works on QSLs and control consider mean-field and discrete systems due to their accessibility, this project aims to go beyond these models to develop QSLs for continuous variable quantum systems while taking realistic inter-particle interactions into account.
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| Outline of Annual Research Achievements |
In the past year I have published 3 main papers on this project. Two of these papers focussed on dynamics of quantum systems in supersymmetric
(SUSY) potentials. SUSY allows to build a hierarchy of degenerate potentials that can be mapped to one another through SUSY operators. In the first work I explored the quench dynamics of many-body states between different SUSY potentials showing that revivals of the initial state are persevered at periodic times, in comparison to quenches between arbitrary potentials [PRR 4 033014 (2022)]. Follow up work on shortcuts to adiabaticity (STAs) showed that SUSY can aid in quantum control, allowing to design STAs for a family of SUSY potentials using only information on their mutual SUSY operators [NJP 24 095001 (2022)]. This also allowed to relate the quantum speed limits (QSLs) of states with respect to their SUSY operators, showing that states in the same hierarchy have closely related QSLs and therefore dynamics.
The role of QSLs was further explored in interacting few-body systems which are used in a quantum heat engine [PRR 5 013088 (2023)]. Here the trap frequency and interaction are dynamically controlled allowing to realize an Otto cycle with enhanced performance due to the interactions. While dynamically controlling the interaction increases the QSL time and limits the power output, the enhancement obtained from the interactions still allows it outperform non-interacting cycles.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Work on this project was delayed due to the COVID-19 pandemic and restrictions to travel in Japan and the rest of the world. For this reason planned conference trips and collaboration visits could not be undertaken. Work done with collaborators has also therefore been delayed, with different projects needing to be finished.
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| Strategy for Future Research Activity |
For the future work I will explore the controlled thermalization of quantum systems coupled to heat reservoirs. Using both shortcuts to adiabaticity and optimal control protocols I plan to design the coupling strength to speed up the equilibration of the system with the environment. Preliminary work will focus on the Caldirola-Kanai model, which allows to describe dissipative dynamics using a dissipationless Hamiltonian. Designing the control scheme for this simpler system should give insight into the full open system dynamics, even providing an approximate STA. Likewise computational control techniques can be used in this case, which rely on numerical optimization of the systems parameters. Furthermore, the quantum speed limit for equilibration can set the minimum timescale for the system to relax and will be dependent on the coupling strength and the spectral density of the bath.
The future plan also involves continuing close collaborations with experimental groups which are currently creating interacting quantum heat engines. The next step in these works is to consider dynamically driving the engines by tuning the trap frequency and interactions. QSLs inherently limit the operation time, STAs allow to approach this limit. In this work I will continue assisting in theoretical support of these groups, providing STAs and bounds on the operation time.
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Report
(2 results)
Research Products
(10 results)
