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 $N$th 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 environment has a sharp frequency cut-off and when control pulses can be taken as instantaneous pulses), dynamical decoupling using nested UDD sequences is a powerful approach for entanglement protection.

11 pages, 3 figures, published version

References in corpus (23)

• Dynamical Decoupling of Open Quantum Systems
• Finite-Time Disentanglement via Spontaneous Emission
• Dynamical suppression of decoherence in two-state quantum systems
• Sudden Death of Entanglement
• Universal dynamical decoupling of a single solid-state spin from a spin bath
• Keeping a Quantum Bit Alive by Optimized $\pi$-Pulse Sequences
• Optimized Dynamical Decoupling in a Model Quantum Memory
• How to Enhance Dephasing Time in Superconducting Qubits
• Dark periods and revivals of entanglement in a two qubit system
• Dynamics of quantum entanglement
• Performance of Deterministic Dynamical Decoupling Schemes: Concatenated and Periodic Pulse Sequences
• Optimal Dynamical Decoherence Control of a Qubit
• Universality of Uhrig dynamical decoupling for suppressing qubit pure dephasing and relaxation
• Experimental Uhrig Dynamical Decoupling using Trapped Ions
• Universal pulse sequence to minimize spin dephasing in the central spin decoherence problem
• Near-optimal dynamical decoupling of a qubit
• Process tomography of dynamical decoupling in a dense optically trapped atomic ensemble
• Master Equation and Control of an Open Quantum System with Leakage
• Quantum error correction may delay, but also cause, entanglement sudden death
• Towards optimized suppression of dephasing in systems subject to pulse timing constraints
• Universal Dynamical Decoupling: Two-Qubit States and Beyond
• Universal Dephasing Control During Quantum Computation
• Optimized Dynamical Decoupling for Time Dependent Hamiltonians

Cited by in corpus (23)

• Demonstration of fidelity improvement using dynamical decoupling with superconducting qubits
• Cavity-based architecture to preserve quantum coherence and entanglement
• Preserving entanglement and nonlocality in solid-state qubits by dynamical decoupling
• Recovering Entanglement by Local Operations
• Combining dynamical decoupling with fault-tolerant quantum computation
• Protection of quantum systems by nested dynamical decoupling
• Protecting entanglement by adjusting the velocities of moving qubits inside non-Markovian environments
• Quadratic Dynamical Decoupling: Universality Proof and Error Analysis
• Decoherence control: Universal protection of two-qubit states and two-qubit gates using continuous driving fields
• Universal dynamical decoupling of multiqubit states from environment
• Protecting and Enhancing Spin Squeezing via Continuous Dynamical Decoupling
• Feshbach Projection Operator Partitioning for Quantum Open Systems: Stochastic Approach
• Pointer States via Engineered Dissipation
• Quadratic Dynamical Decoupling with Non-Uniform Error Suppression
• Optimized Dynamical Decoupling Sequences in Protecting Two-Qubit States
• Spin-echo entanglement protection from random telegraph noise
• Universality proof and analysis of generalized nested Uhrig dynamical decoupling
• Universal Uhrig dynamical decoupling for bosonic systems
• Estimation of the Laser Frequency Nosie Spectrum by Continuous Dynamical Decoupling
• Experimental protection of arbitrary states in a two-qubit subspace by nested Uhrig dynamical decoupling
• Uhrig Dynamical Control of a Three-Level System Via Non-Markovian Quantum State Diffusion
• Dynamical Decoupling in Common Environment
• Higher-order protection of quantum gates: Hamiltonian engineering coordinated with dynamical decoupling