scholarly journals Universal logic gates for quantum-dot electron-spin qubits using trapped quantum-well exciton polaritons

2017 ◽  
Vol 95 (12) ◽  
Author(s):  
Shruti Puri ◽  
Peter L. McMahon ◽  
Yoshihisa Yamamoto
Keyword(s):  
Quantum Dot ◽  
Quantum Well ◽  
Electron Spin ◽  
Logic Gates ◽  
Spin Qubits ◽  
Universal Logic ◽  
Exciton Polaritons

Entanglement dynamics of two electron-spin qubits in a strongly detuned and dissipative quantum-dot-cavity system

2011 ◽  
Vol 84 (6) ◽  
pp. 065010 ◽  
Author(s):  
Shao-Hua Xiang ◽  
Xiao-Peng Deng ◽  
Ke-Hui Song ◽  
Wei Wen ◽  
Zhen-Gang Shi
Keyword(s):  
Quantum Dot ◽  
Electron Spin ◽  
Entanglement Dynamics ◽  
Spin Qubits ◽  
Cavity System

Polariton Devices

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Semiconductor Devices ◽  
Logic Gates ◽  
Light Sources ◽  
Coherent Light ◽  
Final State ◽  
Spintronic Devices ◽  
Exciton Polaritons ◽  
Terahertz Lasers ◽  
Coherence Lengths ◽  
Stimulation Of

Polariton devices offer multiple advantages compared to conventional semiconductor devices. The bosonic nature of exciton polaritons offers opportunity of realisation of polariton lasers: coherent light sources based on bosonic condensates of polaritons. The final state stimulation of any transition feeding a polariton condensate has been used in many proposals such as for terahertz lasers based on polariton lasers. Furthermore, large coherence lengths of exciton-polaritons in microcavities open the way to realisation of polariton transport devices including transistors and logic gates. Being bosonic spin carriers, exciton-polaritons may be used in spintronic devices and polarisation switches. This chapter offers an overview on the existing proposals for polariton devices.

scholarly journals Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
George Gillard ◽  
Ian M. Griffiths ◽  
Gautham Ragunathan ◽  
Ata Ulhaq ◽  
Callum McEwan ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Spin Relaxation ◽  
Nuclear Spin ◽  
Operating Conditions ◽  
External Control ◽  
Spin Qubits ◽  
Fundamental Limits ◽  
Trade Offs ◽  
Wide Range ◽  
Spin Qubit

AbstractCombining external control with long spin lifetime and coherence is a key challenge for solid state spin qubits. Tunnel coupling with electron Fermi reservoir provides robust charge state control in semiconductor quantum dots, but results in undesired relaxation of electron and nuclear spins through mechanisms that lack complete understanding. Here, we unravel the contributions of tunnelling-assisted and phonon-assisted spin relaxation mechanisms by systematically adjusting the tunnelling coupling in a wide range, including the limit of an isolated quantum dot. These experiments reveal fundamental limits and trade-offs of quantum dot spin dynamics: while reduced tunnelling can be used to achieve electron spin qubit lifetimes exceeding 1 s, the optical spin initialisation fidelity is reduced below 80%, limited by Auger recombination. Comprehensive understanding of electron-nuclear spin relaxation attained here provides a roadmap for design of the optimal operating conditions in quantum dot spin qubits.

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