Classical phase synchronization in dissipative non-Hermitian coupled systems
Jonas Rohn,
Kai Phillip Schmidt,
Claudiu Genes
Physical Review A
108
023721
(2023)
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We study the interplay between non-Hermitian dynamics and classical phase synchronization in a system of N bosonic modes commonly coupled to an auxiliary, driven mode. For any set of non-Hermitian bipartite interactions between the auxiliary and other modes, the system evolves towards a phase synchronized state. We provide analytical and numerical evidence of such classical phase synchronization for systems ranging from a few modes to the macroscopic limit of large N and analyze the effects of inhomogeneous frequency broadening and robustness under the action of external thermal noise.
Theory of phase-adaptive parametric cooling
Alekhya Ghosh,
Pardeep Kumar,
Christian Sommer,
Fidel G. Jimenez,
Vivishek Sudhir,
Claudiu Genes
Physical Review A
107
053521
(2023)
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We propose an adaptive phase technique for the parametric cooling of mechanical oscillators. Our scheme calls for a sequence of periodic adjustments of the phase of a parametric modulation of the mechanical oscillator that is conditioned on measurements of its two quadratures. The technique indicates an exponential loss of thermal energy at initial high occupancies, similar in performance to other optomechanical techniques such as cold-damping or cavity self-cooling. As the quantum ground state is approached, the phase adaptive scheme leads to residual occupancies at the level of a few phonons owing to the competition between parametric amplification of quantum fluctuations and the feedback action.
Linear optical elements based on cooperative subwavelength emitter arrays
Nico S. Baßler,
Michael Reitz,
Kai P. Schmidt,
Claudiu Genes
Optics Express
31
(4)
6003-6026
(2023)
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We describe applications of two-dimensional subwavelength quantum emitter arrays as efficient optical elements in the linear regime. For normally incident light, the cooperative optical response, stemming from emitter-emitter dipole exchanges, allows the control of the array’s transmission, its resonance frequency, and bandwidth. Operations on fully polarized incident light, such as generic linear and circular polarizers as well as phase retarders can be engineered and described in terms of Jones matrices. Our analytical approach and accompanying numerical simulations identify optimal regimes for such operations and reveal the importance of adjusting the array geometry and of the careful tuning of the external magnetic fields amplitude and direction.<br><br>
