CaSTL Seminar with Stephen K. Gray

Date: 
Thursday, December 10, 2015 - 01:00
Location: 
2201 Natural Sciences II
Speakers: 
Stephen K. Gray, Center for Nanoscale Materials, Argonne National Laboratory
Event Title: 
Generation of Entanglement in Hybrid Quantum Dot/Plasmonic Systems with Ultrafast Laser Pulses
Host: 
Ara Apkarian

We propagate the quantum mechanical density matrix, including dephasing, spontaneous emission and dissipation to study systems composed of two, three or four quantum dots in proximity to a plasmonic system when exposed to an ultrafast optical pulse [1].  The plasmonic system could be a single metal nanoparticle or an array of metal nanoparticles or some other plasmonic structure and serves to enhance the local electric fields that arise due to the pulse.  We have previously studied a single quantum dot interacting with a plasmonic system and demonstrated how Fano resonances in transient optical response can be reshaped with ultrafast laser pulses [2]. Our model treated the quantum dot as a two-state system and the plasmonic system as a boson.  Dissipation of the plasmon and dephasing and spontaneous emission of the quantum dots are included via the Lindblad formalism.  Here we extend this model to multiple quantum dots being present and show that it is possible to induce entanglement in systems with two or more  quantum dots by starting from the ground state and using  pulsed laser excitation. Significant bipartite (two quantum dot case) and multiple bipartite entanglements (three or quantum dot cases), as measured by concurrence [3], are found. Finally, we show how a repeating laser pulse pattern can be used to prepare the system in an entangled state for an arbitrary length of time. These results represent positive indicators for the eventual use of such systems in quantum information applications.

 

References:

[1] M. Otten, R. A. Shah, N. F. Scherer, M. Min, M. Pelton, and S. K. Gray,  Phys. Rev. B 92, 125432 (2015).

[2] R. A. Shah., Scherer, N. F. Scherer, M. Pelton, and S. K. Gray,  Phys. Rev. B 88, 075411 (2013).

[3] W. K. Wootters,  Phys. Rev. Lett. 80, 2245-2248 (1998).

 

The submitted manuscript has been created by UChicago Argonne, LLC,  Operator of Argonne National Laboratory ("Argonne"). Argonne, a U.S.  Department of Energy Office of Science laboratory, is operated under Contract  No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said  article to reproduce, prepare derivative works, distribute copies to the public, and  perform publicly and display publicly, by or on behalf of the Government.