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Title: Protecting unknown two-qubit entangled states by nesting Uhrig's dynamical decoupling sequences

Abstract

Future quantum technologies rely heavily on good protection of quantum entanglement against environment-induced decoherence. A recent study showed that an extension of Uhrig's dynamical decoupling (UDD) sequence can (in theory) lock an arbitrary but known two-qubit entangled state to the Nth order using a sequence of N control pulses [Mukhtar et al., Phys. Rev. A 81, 012331 (2010)]. By nesting three layers of explicitly constructed UDD sequences, here we first consider the protection of unknown two-qubit states as superposition of two known basis states, without making assumptions of the system-environment coupling. It is found that the obtained decoherence suppression can be highly sensitive to the ordering of the three UDD layers and can be remarkably effective with the correct ordering. The detailed theoretical results are useful for general understanding of the nature of controlled quantum dynamics under nested UDD. As an extension of our three-layer UDD, it is finally pointed out that a completely unknown two-qubit state can be protected by nesting four layers of UDD sequences. This work indicates that when UDD is applicable (e.g., when the environment has a sharp frequency cutoff and when control pulses can be taken as instantaneous pulses), dynamical decoupling using nested UDD sequencesmore » is a powerful approach for entanglement protection.« less

Authors:
; ;  [1];  [1];  [2];  [2]
  1. Department of Physics, National University of Singapore, 117542 (Singapore)
  2. (Singapore)
Publication Date:
OSTI Identifier:
21528617
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 82; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevA.82.052338; (c) 2010 The American Physical Society
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CONTROL; COUPLING; DECOUPLING; PULSES; QUANTUM DECOHERENCE; QUANTUM ENTANGLEMENT; QUBITS; TWO-BODY PROBLEM; INFORMATION; MANY-BODY PROBLEM; QUANTUM INFORMATION

Citation Formats

Mukhtar, Musawwadah, Soh, Wee Tee, Saw, Thuan Beng, Gong, Jiangbin, Centre for Computational Science and Engineering, National University of Singapore, 117542, and NUS Graduate School for Integrative Sciences and Engineering, Singapore 117597. Protecting unknown two-qubit entangled states by nesting Uhrig's dynamical decoupling sequences. United States: N. p., 2010. Web. doi:10.1103/PHYSREVA.82.052338.
Mukhtar, Musawwadah, Soh, Wee Tee, Saw, Thuan Beng, Gong, Jiangbin, Centre for Computational Science and Engineering, National University of Singapore, 117542, & NUS Graduate School for Integrative Sciences and Engineering, Singapore 117597. Protecting unknown two-qubit entangled states by nesting Uhrig's dynamical decoupling sequences. United States. doi:10.1103/PHYSREVA.82.052338.
Mukhtar, Musawwadah, Soh, Wee Tee, Saw, Thuan Beng, Gong, Jiangbin, Centre for Computational Science and Engineering, National University of Singapore, 117542, and NUS Graduate School for Integrative Sciences and Engineering, Singapore 117597. Mon . "Protecting unknown two-qubit entangled states by nesting Uhrig's dynamical decoupling sequences". United States. doi:10.1103/PHYSREVA.82.052338.
@article{osti_21528617,
title = {Protecting unknown two-qubit entangled states by nesting Uhrig's dynamical decoupling sequences},
author = {Mukhtar, Musawwadah and Soh, Wee Tee and Saw, Thuan Beng and Gong, Jiangbin and Centre for Computational Science and Engineering, National University of Singapore, 117542 and NUS Graduate School for Integrative Sciences and Engineering, Singapore 117597},
abstractNote = {Future quantum technologies rely heavily on good protection of quantum entanglement against environment-induced decoherence. A recent study showed that an extension of Uhrig's dynamical decoupling (UDD) sequence can (in theory) lock an arbitrary but known two-qubit entangled state to the Nth order using a sequence of N control pulses [Mukhtar et al., Phys. Rev. A 81, 012331 (2010)]. By nesting three layers of explicitly constructed UDD sequences, here we first consider the protection of unknown two-qubit states as superposition of two known basis states, without making assumptions of the system-environment coupling. It is found that the obtained decoherence suppression can be highly sensitive to the ordering of the three UDD layers and can be remarkably effective with the correct ordering. The detailed theoretical results are useful for general understanding of the nature of controlled quantum dynamics under nested UDD. As an extension of our three-layer UDD, it is finally pointed out that a completely unknown two-qubit state can be protected by nesting four layers of UDD sequences. This work indicates that when UDD is applicable (e.g., when the environment has a sharp frequency cutoff and when control pulses can be taken as instantaneous pulses), dynamical decoupling using nested UDD sequences is a powerful approach for entanglement protection.},
doi = {10.1103/PHYSREVA.82.052338},
journal = {Physical Review. A},
number = 5,
volume = 82,
place = {United States},
year = {Mon Nov 15 00:00:00 EST 2010},
month = {Mon Nov 15 00:00:00 EST 2010}
}