2019 Fiscal Year Research-status Report
Expanded bandwidth for production of the optical vortex by cyclotron radiation
| Project/Area Number |
18K03466
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
ガーモン サバンナスターリング 大阪府立大学, 理学(系)研究科(研究院), 助教 (30733860)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | continuum threshold / optical vortex / non-Markovian decay / bound state in continuum / exceptional point |
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| Outline of Annual Research Achievements |
I have made progress on two works related to this project. In the first, I have studied a situation in which non-Markovian dynamics associated with the continuum threshold (waveguide cut-off mode, for example) in quantum systems can be enhanced by using the properties of a so-called Bound State in Continuum (BIC). A bound state in continuum should be understood as an interference effect that occurs in quantum systems such that the exponential decay associated with the usual resonance is suppressed. In Ref. [1] I have shown that by preparing the system in an initial state that lies orthogonal to the BIC, one can avoid both the exponential decay associated with a resonance as well as the stability associated with the BIC itself to obtain non-Markovian decay on all timescales.
For the second project, I gave a virtual talk based on work demonstrating non-Markovian dynamics influenced by an anomalous exceptional point (EP) appearing at the threshold quite generally in 1-D systems, such as a quantum emitter traveling in an electromagnetic waveguide. An EP is a point in the parameter space of a given open quantum system at which two eigenstates coalesce. We showed this EP gives rise to an unusual non-Markovian dynamics in the form of a power law with a fractional exponent, which gives an opportunity for micro control.
[1] Phys. Rev. A 99, 010102R (2019)
[2] S. Garmon, American Physical Society March Meeting 2020, virtual presentation, https://virtualmarchmeeting.com/presentations/anomalous-exceptional-point-and-non-markovian-purcell-effect-at-threshold-in-1-d-continuum-systems
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
I have made good progress on two works on non-Markovian dynamics in general systems consisting of a quantum emitter coupled to a continuum, such as a charged particle undergoing cyclotron motion inside a waveguide. In the next stage I will publish the previously mentioned second work on the anomalous exceptional point appearing at threshold in 1-D systems and I will examine these and other effects more specifically in the context of the optical vortex production.
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| Strategy for Future Research Activity |
While the previous two projects on non-Markovian decay apply quite generally in open quantum systems, in future work I will apply them more specifically to the problem of optical vortex production in a waveguide. I will also examine further specific cases that may provide opportunities for the micro-control of optical vortex production. And I will finish the paper on the second project.
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| Causes of Carryover |
Because several conferences in Spring 2020 were unfortunately cancelled due to the Corona virus crisis, I was not able to use a significant portion of the funds as planned in the previous fiscal year. Hopefully the situation will improve in the 2020 fiscal year.
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