Hamiltonian design in atom-light interactions with rubidium - - PowerPoint PPT Presentation

Hamiltonian design in atom-light interactions with rubidium ensembles

• M. Dabrowski, R. Chrapkiewicz and W. Wasilewski

Faculty of Physics, University of Warsaw 22nd June, Quantum Technologies VI Conference

Prospective applications of optical quantum memories

metrology, magnetometry

Bussieres et al., J. Mod. Opt. (2013)

linear quantum computer, quantum logic gates heralded photons source, quantum sequencer single-photon detector quantum repeaters, quantum Internet non-linear interaction, four-wave mixing

Light-atom interface via Raman scattering

Stokes scattering

(spontaneous process)

anti-Stokes scattering

(atomic coherence needed)

effectively: two-level system, model toy of quantum optics collective atomic excitation → spin wave

Single photons assets: easy to controlled manipulation weak interaction with environment information storage inside the 87Rb atoms

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How the off-resonant Raman memory works?

write laser + Stokes scattered photon read laser + anti-Stokes scattered photon

• ptical pumping

spin wave storage

Experimental demonstration

Technical challenges:

• buffer gas and temperature
• spectral laser beams filtering
• laser frequency stabilization
• pump power fluctuations
• geometry of laser beams

simplified version of experimental setup phase-matching is important!

write region read region

Chrapkiewicz et al., Opt. Commun. (2014)

write-in readout storage

Spatially multimode quantum memory

many spin waves inside the cell

diffusion limited storage

• M. Parniak et al., Appl. Phys. B (2013)

Exponential growth of retrieved signal

changing dynamics of readout, ability to amplifying signal light-atom interface regulation, Hamiltonian engineering

• M. Dąbrowski et al.,
• Opt. Express (2014)

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How it REALLY works? - our predictions

coherent „classical” readout four-wave mixing (FWM) process incoherent re-writing process during the memory readout

Theoretical model of readout process

Hamiltonian in the interaction picture

four-wave mixing process (during the readout)

write-in readout

mean number of scattered photons

Spatially resolved correlation maps

correlation coefficient

„classical” pure readout four-wave mixing (FWM)

Hamiltonian design via FWM

How to improve your memory?

numerical simulation experimental realization non-cloning theorem BREAKING in the experiment ?!

efficiency of correlated signal retrieval

Conclusion, perspectives and future plans

Information storage could be realized via off-resonant Raman scattering inside the warm rubidum vapours Hamiltonian engineering is a potential tool for amplifying signal in the readout process of atomic quantum memory (Probably) we produce in our experimental setup so called two mode squeezed vacuum state → work in progress ... In the near future we plan to measure EPR-like correlations Next step would be cooling atomic memory and building MOT for better manipulation

• f atomic internal states and interactions

Thank you for your attention!

Quantum Memories Lab

• Ass. Prof. Dr. W. Wasilewski
• R. Chrapkiewicz
• M. Dąbrowski
• M. Parniak
• J. Iwaszkiewicz
• M. Piasecki