scholarly journals Stable collective dynamics of two-level systems coupled by dipole interactions

2017 ◽  
Vol 95 (3) ◽  
Author(s):  
C. D. Parmee ◽  
N. R. Cooper
Keyword(s):  
Collective Dynamics ◽  
Dipole Interactions ◽  
Two Level Systems

scholarly journals Quantum emitter dipole–dipole interactions in nanoplasmonic systems

2017 ◽  
Vol 31 (24) ◽  
pp. 1740006 ◽  
Author(s):  
Marek Nečada ◽  
Jani-Petri Martikainen ◽  
Päivi Törmä
Keyword(s):  
Multiple Scattering ◽  
Dipole Interaction ◽  
Energy Spectra ◽  
Dye Molecules ◽  
Metallic Nanoparticle ◽  
Scaling Properties ◽  
Light Spectra ◽  
Quantum Emitter ◽  
Dipole Interactions ◽  
Two Level Systems

We introduce a generalized Dicke-like model to describe two-level systems coupled with a single bosonic mode. In addition, the two-level systems mutually interact via direct dipole–dipole interaction. We apply the model to an ensemble of dye molecules coupled to a plasmonic excitation in a metallic nanoparticle and study how the dipole–dipole interaction and configurational randomness introduced to the system affect the energy spectra. Comparing the system eigenenergies obtained by our model with the light spectra from a multiple-scattering simulation, we suggest a way to identify dark modes in our model. Finally, we perform a parameter sweep in order to determine the scaling properties of the system and to classify the regions of the parameter space where the dipole–dipole interactions can have significant effects.

scholarly journals Decoherent Excitation of Transverse Free Currents in Dielectric Liquids via Inter-Molecular Interactions

2021 ◽  
Vol 9 ◽  
Author(s):  
C. S. DiLoreto ◽  
C. Rangan
Keyword(s):  
Short Duration ◽  
Incident Light ◽  
Optical Scattering ◽  
Lower Field ◽  
Electromagnetic Pulses ◽  
Dielectric Liquids ◽  
Dipole Interactions ◽  
Linearly Polarized ◽  
Two Level Systems ◽  
Dense Cluster

We present a theoretical model for a class of optical scattering experiments in which short-duration, linearly-polarized electromagnetic pulses scatter off dielectric liquids. The pattern of scattering, particularly in the transverse direction, indicates that significant free currents are generated in the direction orthogonal to the polarization of the incident light. Modelling the target as a dense cluster of two-level systems, we show that transverse free currents are produced by short duration, electric-dipole interactions between proximate molecules, and result in scattering patterns similar to those observed in the experiments. Calculations provide a rationale for why these scattering patterns are not observed in the same molecules at lower densities or with lower field intensities. These features make this model a relevant alternative to proposed transverse optical magnetism theories.

Tuning the Magnetic Vortex State in Magnetite Nanodiscs for Remote Control of Biological Signalling

2019 ◽  
Author(s):  
Danijela Gregurec ◽  
Alexander W. Senko ◽  
Andrey Chuvilin ◽  
Pooja Reddy ◽  
Ashwin Sankararaman ◽  
...  
Keyword(s):  
Remote Control ◽  
Ion Channels ◽  
Ground State ◽  
Magnetic Particles ◽  
Colloidal Stability ◽  
Vortex State ◽  
Magnetic Vortex ◽  
Electron Holography ◽  
Dipole Interactions ◽  
Magnetite Particles

In this work, we demonstrate the application of anisotropic magnetite nanodiscs (MNDs) as transducers of torque to mechanosensory cells under weak, slowly varying magnetic fields (MFs). These MNDs possess a ground state vortex configuration of magnetic spins which affords greater colloidal stability due to eliminated dipole-dipole interactions characteristic of isotropic magnetic particles of similar size. We first predict vortex magnetization using micromagnetic stimulations in sub-micron anisotropic magnetite particles and then use electron holography to experimentally investigate the magnetization of MNDs 98–226 nm in diameter. When MNDs are coupled to MFs, they transition between vortex and in-plane magnetization allowing for the exertion of the torque on the pN scale, which is sufficient to activate mechanosensitive ion channels in cell membranes.<br>

Estimate of the conversion time in macroscopic two-level systems

1983 ◽  
Vol 56 (3) ◽  
pp. 897-903 ◽  
Author(s):  
E. K. Bashkirov ◽  
N. N. Bogolyubov ◽  
A. S. Shumovskii
Keyword(s):  
Two Level Systems ◽  
Conversion Time
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